Identifying root cause of water ingress from outer to inner leaf - cavity wall

makeorbrake

Have a scenario with my house whereby there’s water ingress from outer leaf to inner leaf due to defective external rendering. Have had this verified professionally – and in a claims scenario. As part of that process, I need to go one step further and open up a section of the gable wall – and try to identify specifically how the water is transferring from outer to inner leaf. Engineer has indicated it may be for one of the following reasons;

- It’s simply getting through the render and transferring across via the wall ties.
- There are mortar snots in the cavity/on the ties and this is resulting in the transfer of water
- The insulation is not fitted properly to the inner leaf – resulting in the transfer of water.

Naturally, I’ll be having the engineer examine wall once it’s been opened. Notwithstanding that, I’d like to be as well informed myself as Ì possibly can be as to how the precise defect can be identified and proven beyond doubt.
If it’s the first item listed above, how do I demonstrate this i.e. that water is simply running along the ties? The second one (mortar snots) seems pretty straightforward. As regards the insulation, what am I looking for there? I’ve a feeling this won’t come into play as I *think* it's bead insulation as opposed to rigid polystyrene (can see beads when I check the ESB meter on that wall).

Are there any other causes that I can look for other than the three listed above?

_Brian

Two things strike me as likely.
Mad you say through messy brickwork the mortar a its on wall ties is carrying significant water across.

It may be beaded insulation but there were limits as to the application of this on standard walls. In areas of the country where driving rain is common it isn't recommended for use for this reason. From memory there is a map showing areas where it shouldn't be used.

Metric Tensor

If there are no mortar snots on the ties then look to see if there is a "drip" on them (a kink in the middle) - there probably isn't if it's a full fill insulation but if there is one it's unlikely the water is crossing the ties. You could drop some water onto them yourself and see do the water drips fall towards the outside of the tie or the inside.

The beaded insulation is not recommended for brick outer leaf walls in areas with high driving rain index. If your render is poor your block wall could be porous like a brick one and essentially be subject to the same conditions. Having said that I have seen brick walls in areas of quite high driving rain with bead pumped into the cavity where it shouldn't have been and there hasn't been any water crossing the cavity.

What way is the water crossing the cavity manifesting inside and at what locations is the problem happening?

Calahonda52

Metric Tensor wrote: »

What way is the water crossing the cavity manifesting inside and at what locations is the problem happening?

This is key as well as what OP means by this:
Have had this verified professionally.
With an unopened wall, thats a mighty call:D

What about faulty DPC detailing around windows/lintels etc?

Whats the roofing detail, overhang or barge?

The one thing about water is that the entry and exit points are never close together.

Metric Tensor

Barges, parapet walls, unsealed stonework, poor cavity trays ... projections such as conservatories etc. There's a lot of ways water can get in without the render necessarily being faulty.

And even in the absence of any external render you're not guaranteed to have water crossing the cavity.

Can you let us know how it shows up inside OP?

Coles

I don't see how you have had anything 'verified professionally' when you aren't clear even what kind of insulation is in the cavity. That's a key fact.

I agree with Calahonda52. More likely to be DPC detailing (parapet wall, lintels etc.). I'd be very surprised if the render alone was the culprit.

makeorbrake

_Brian wrote: »

It may be beaded insulation but there were limits as to the application of this on standard walls. In areas of the country where driving rain is common it isn't recommended for use for this reason. From memory there is a map showing areas where it shouldn't be used.

It's manifesting on the gable wall of the house only - the one that gets the full force of wind n' driving rain. If you (or anyone reading this) happen to have a link re. map, I'd be keen to check that out.

Metric Tensor wrote: »

The beaded insulation is not recommended for brick outer leaf walls in areas with high driving rain index.

Would you happen to have a link to any documentation on that?

Metric Tensor wrote: »

What way is the water crossing the cavity manifesting inside and at what locations is the problem happening?

The internal surface of that wall is bubbling up - with efflorescence marks evident from a height of 6ft to the base of the wall - in both the living room and kitchen (both on the internal surface of that gable wall). On the exterior, there are a series of long horizontal cracks in the render - a few metres in length for each - about 5 or 6 of them.
Nothing is evident on the upstairs wall internal surface but then that complete surface is tiled - so difficult to assess.

Calahonda52 wrote: »

This is key as well as what OP means by this:
Have had this verified professionally.
With an unopened wall, thats a mighty call:D

What about faulty DPC detailing around windows/lintels etc?

Whats the roofing detail, overhang or barge?

The one thing about water is that the entry and exit points are never close together.

Calahonda52 wrote: »

This is key as well as what OP means by this:
Have had this verified professionally.
With an unopened wall, thats a mighty call:D

What about faulty DPC detailing around windows/lintels etc?

Whats the roofing detail, overhang or barge?

The one thing about water is that the entry and exit points are never close together.

Coles wrote: »

I don't see how you have had anything 'verified professionally' when you aren't clear even what kind of insulation is in the cavity. That's a key fact.

I agree with Calahonda52. More likely to be DPC detailing (parapet wall, lintels etc.). I'd be very surprised if the render alone was the culprit.

Yup - ok, I guess I wanted to get across the point that I've had an engineer carry out an initial assessment (so that people understood I had taken that step). There are a series of horizontal cracks - over a few metres in length evident on that gable wall - they're a few mm wide. He is not verifying HOW the water crosses - but is indicating a failure of the render itself. That's the reason for the opening up works.

I take your points re. DPC detailing and roofing detail (overhang - not barge). There's only one window on that gable wall - small bathroom window. How can that be assessed for water ingress?? As regards the main dpc, I assume that can be ruled out if damp is showing at a height of 6ft inside?

Metric Tensor

Two quick questions -

What height are the external cracks at?

And what type of roof do you have - hip or gable ended?

Edit: Those cracks might be indicative of a problem rather than the root problem.

Calahonda52

OP: any chance of a few pictures of the cracked gable.
Op: back to this: there’s water ingress from outer leaf to inner leaf due to defective external rendering. Have had this verified professionally
and
He is not verifying HOW the water crosses

I think that you may be over interpreting what he is saying, let me put it this way, this would not last 2 mins under defence council cross examination.

You may have a structural issue which MT is alluding to: hip roof, no ring beam, not enough ties, cavity too wide, etc
and the other clue is:
Tiled wall in room above suggests a bathroom, suggests imbedded pipework suggests....leaks, [perhaps I have too much vino for Tuesday:)]

While I don't expect it, do first floor joists embed in gable wall?

The internal surface of that wall is bubbling up - with efflorescence marks

That a lot of water to jump across, but am happy to be wrong.

My final point here is that opening up a cavity wall gable with bead insulation is a world of hurt and might show zip, costing money that might be better spent on remedial rather than destructive work.

Let me put it this way, if you had no one to sue, or if the builder has gone ^^ up, would you still open up?
Getting a judgement against a sole trader or a man of straw is worthless

Metric Tensor

Calahonda52 said exactly what I was thinking but didn't have the balls to say out loud!!!

Look for leaks and/or structural problems before whacking a big hole in your wall.

Would love to see some pictures too!

Metric Tensor

makeorbrake wrote: »

Would you happen to have a link to any documentation on that?

Just to answer this (although I'm not sure it's relevant in this case) it will be given in the agrement cert for the bead in question.

So find out what brand of bead is in the wall (or if you don't know for investigative purposes you can pick a roughly similar one) and then google "XYZ Brand Bead NSAI Agrement Certificate" and read the section relating to exposure.

makeorbrake

Metric Tensor wrote: »

Two quick questions -
What height are the external cracks at?
And what type of roof do you have - hip or gable ended?
Edit: Those cracks might be indicative of a problem rather than the root problem.

See pics below

Calahonda52 wrote: »

OP: any chance of a few pictures of the cracked gable.

Sure - see below.

Calahonda52 wrote: »

Op: back to this: there’s water ingress from outer leaf to inner leaf due to defective external rendering. Have had this verified professionallyand He is not verifying HOW the water crosses
I think that you may be over interpreting what he is saying, let me put it this way, this would not last 2 mins under defence council cross examination.

So the opinion of a professional engineer doesn't carry any credibility? He maintains that there is no other moisture source resulting in the internal damage. The other party has not demonstrated otherwise.

Calahonda52 wrote: »

My final point here is that opening up a cavity wall gable with bead insulation is a world of hurt and might show zip, costing money that might be better spent on remedial rather than destructive work.

It grates my gears that I have to go to this length - I feel it's unnecessary. The other party maintains that the rendering is NOT necessary to insure the watertightness of the dwelling. They maintain that I have not demonstrated specifically HOW the water is finding its way to the inside surface. This is going a certain direction - and I have to nail things down before proceeding to the next step. Do I want to do it - most definitely not.

Calahonda52 wrote:

Let me put it this way, if you had no one to sue, or if the builder has gone ^^ up, would you still open up?
Getting a judgement against a sole trader or a man of straw is worthless

No on the first question. On the man of straw, this isn't a 'man of straw' but a party to matters that has responsibilities - the essence of which being that I shouldn't have been sold a defective property.

external
internal1
internal2

Metric Tensor wrote:

So find out what brand of bead is in the wall (or if you don't know for investigative purposes you can pick a roughly similar one) and then google "XYZ Brand Bead NSAI Agrement Certificate" and read the section relating to exposure.

Thanks for that. Is it not highly relevant - if it was proven an inappropriate material had been used (resulting in this whole issue)?

Metric Tensor

Have you posted here before OP - I think I've seen those photographs before!

We're not allowed give structural advice here but I am going to give some gambling advice. If I was a betting man I would place a nice wager that when you open up the wall those horizontal cracks are caused by some sort of issue with the wall ties. Possibly they are rusty or otherwise compromised. There's a publication by BRE called "Cracking in Buildings" - ask your Engineer if he can access it. Chapter 6 describes an issue with horizontal cracking very like your own.

As for the moisture ingress - it could be related to the wall tie issue. It could be mortar snots or it may be something completely different.

Is there a radiator behind that sofa?

Have you physically seen the cavity insulation at any opening in the wall - meter box or similar?

makeorbrake wrote: »

Is it not highly relevant - if it was proven an inappropriate material had been used (resulting in this whole issue)?

Your wall is rendered. It is not inappropriate to use it in your case. It was just part of a general discussion that if moisture somehow got past the render then based on inference from the certs discussed it MAY be possible for water to cross the pumped cavity. As I said - I've never seen it happen - even in walls that have no render! Your wall is "rendered" (note the inverted commas!) so there's no argument that appropriately certified pumped bead would be inappropriate.

makeorbrake

Metric Tensor wrote: »

Have you posted here before OP - I think I've seen those photographs before!

You're quite right - good memory. Posted some time ago. I'm a little bit further on than I was back then - progress has been very slow in between times (but I'll get there).

Metric Tensor wrote: »

We're not allowed give structural advice here but I am going to give some gambling advice. If I was a betting man I would place a nice wager that when you open up the wall those horizontal cracks are caused by some sort of issue with the wall ties. Possibly they are rusty or otherwise compromised. There's a publication by BRE called "Cracking in Buildings" - ask your Engineer if he can access it. Chapter 6 describes an issue with horizontal cracking very like your own.

Thanks for the tip on that. Should the opening be made along one of those cracks then?

Metric Tensor wrote: »

As for the moisture ingress - it could be related to the wall tie issue. It could be mortar snots or it may be something completely different.

I guess that's the difficulty - i.e. that I may not find specifically what's needed but then I need to try - as it would rule out a lot of uncertainty if this ends up in litigation.

Metric Tensor wrote: »

Is there a radiator behind that sofa?

No rad. There's a rad in the Kitchen - along that wall alright - but not the front room. If the rad was an issue, surely the moisture wouldn't defy gravity (as it's up as far as head height?

Metric Tensor wrote: »

Have you physically seen the cavity insulation at any opening in the wall - meter box or similar?

Nope. I've just seen some 'beads' fall out when accessing the ESB meter (that's fixed into the side of the wall).

Metric Tensor wrote: »

Your wall is rendered. It is not inappropriate to use it in your case. It was just part of a general discussion that if moisture somehow got past the render then based on inference from the certs discussed it MAY be possible for water to cross the pumped cavity. As I said - I've never seen it happen - even in walls that have no render! Your wall is "rendered" (note the inverted commas!) so there's no argument that appropriately certified pumped bead would be inappropriate.

Ok, but IF they concede that there's an issue with the render - and claim that render has no function when it comes to watertightness, would the combination of compromised render together with the use of that material mean that I only need to prove that the render is defective? Is it a case that whilst it's suggested that certain bead insulation shouldn't be used in some areas, it's ok to use in said areas if the dwelling is rendered?

Metric Tensor

makeorbrake wrote: »

Thanks for the tip on that. Should the opening be made along one of those cracks then?

It wouldn't be right for me to give advice in that regard because I don't know anywhere near enough about the house and even if I did give advice you shouldn't follow it because I could be any auld crank on the internet. You have engaged a structural engineer - he/she is the one to give advice on that.

makeorbrake wrote: »

I guess that's the difficulty - i.e. that I may not find specifically what's needed but then I need to try - as it would rule out a lot of uncertainty if this ends up in litigation.

Yes and no. If you open up with a view to litigation you should have a whole fleet of people present to make it of any use. Sample list:

1. You
2. Your engineer.
3. The contractor/developer/vender
4. An engineer working for the contractor/developer/vendor
5. An engineer working for your home insurance company
6. An engineer working for the contractor/developer/vendor's insurers
7. A Homebond representative if they are involved.

If you just open it up on your own you leave yourself open to claims that you made the problem worse by your activities.

makeorbrake wrote: »

No rad. There's a rad in the Kitchen - along that wall alright - but not the front room. If the rad was an issue, surely the moisture wouldn't defy gravity (as it's up as far as head height?

The reason I asked is that moisture will condense and behave differently directly above a rad because the heat from the rad rises warming the blocks, wall and air directly above the radiator to a higher temperature than the surrounding areas. If you look at poorly ventilated properties you sometimes see discolouration and mould growth above the radiators. I was just wondering if heat could be an issue that is feeding into the dampness you see on your wall. I don't have the answer - just asking the question!

makeorbrake wrote: »

Nope. I've just seen some 'beads' fall out when accessing the ESB meter (that's fixed into the side of the wall).

Hmmm ... there's better informed posters than I around here who might be helpful to you with regards to what you should and shouldn't see.

makeorbrake wrote: »

Ok, but IF they concede that there's an issue with the render - and claim that render has no function when it comes to watertightness, would the combination of compromised render together with the use of that material mean that I only need to prove that the render is defective?

This comes down to the wording of the agrement cert. It lists the types of walls in which the bead can be used in both exposed and not so exposed areas. Read it carefully and have your engineer read it. Where are you based?

makeorbrake wrote: »

Is it a case that whilst it's suggested that certain bead insulation shouldn't be used in some areas, it's ok to use in said areas if the dwelling is rendered?

Yes - pretty much. The bead can be used in X, Y and Z wall type in some areas whereas in other it can only be used in X and Y wall type.

makeorbrake

Metric Tensor wrote: »

It wouldn't be right for me to give advice in that regard because I don't know anywhere near enough about the house and even if I did give advice you shouldn't follow it because I could be any auld crank on the internet. You have engaged a structural engineer - he/she is the one to give advice on that.

Understand totally. I guess I couldn't help myself but to ask. It's kind of important to me that this saga ends well...and with that, I'm trying to educate myself as best I can (in addition to taking professional advice).

Metric Tensor wrote: »

Yes and no. If you open up with a view to litigation you should have a whole fleet of people present to make it of any use. Sample list:

1. You
2. Your engineer.
3. The contractor/developer/vender
4. An engineer working for the contractor/developer/vendor
5. An engineer working for your home insurance company
6. An engineer working for the contractor/developer/vendor's insurers
7. A Homebond representative if they are involved.

If you just open it up on your own you leave yourself open to claims that you made the problem worse by your activities.

It really only involves 1,2 & 7 - informed by 7 that It's incumbent on me to go that route and prove my case beyond doubt - whilst also giving them access for their own assessment.

Metric Tensor wrote: »

The reason I asked is that moisture will condense and behave differently directly above a rad ...I don't have the answer - just asking the question

Yup, and I appreciate you asking the question rather than not.

Metric Tensor wrote: »

This comes down to the wording of the agrement cert. It lists the types of walls in which the bead can be used in both exposed and not so exposed areas. Read it carefully and have your engineer read it. Where are you based?
Yes - pretty much. The bead can be used in X, Y and Zwall type in some areas whereas in other it can only be used in X and Y wall type.

I'm based in the West of Ireland. Checked one Agrement Cert just now (of course, I don't know if its the right one) for beaded insulation and their map shows I'm located in a severe exposure area...but just like you said, as long as its rendered and a minimum cavity gap of 90mm, then it's ok to use....but then if the render was defective....
Edit: Checked another one and they say 'minimum 40mm cavity'.
This is a pic of the meter box - which seems to suggest bead fill - unless that was just used around the box itself?

tedimc

Not offering any structural advice, but just a thought before you go cutting sections out of your wall.

You can now get pin-hole cameras very cheap online(with built in LED lighting) - you could always drill a few small holes (10mm) into the cavity and have a look around using a camera, before identifying the best point to open up a large inspection hole. It may help for example to spot mortar snots, rusted wall-ties, misplaced insulation, etc.

makeorbrake

@tedimc: Appreciate that - and I guess it makes a lot more sense. That said, this is what the other party has been insisting on (and for reasons I won't go into, it's taken forever to get to this point).

Would the cameras still function where there's bead insulation in place in the cavity? i.e. is it still possible to view ties, etc with the bead in the way?

tedimc

Oh yeah - I think you will end up opening up a section of the wall to prove the point, but I think it would be hit or miss and you don't want to end up cutting more of the block than is absolutely necessary out.

The camera may help you from the perspective of knowing exactly where to cut/open. And 20 10mm holes are easier to fill/patch than a single large 200mm hole.

It should be able to push the bead out of the way, but you probably wouldn't have a lot of control over the direction once you enter the cavity. However, some of the 'professional' options have the ability to direct the probe/camera I think. The types used in drain inspections may be too large, but smaller ones may be used for engine or machinery inspection.

Alternatively - a thermal imaging camera may give some clues without the need to drill at all? It wouldn't be very detailed, but may help identify a particular area, or even where the wall ties are located?

On another note - if worst comes to the worst and you don't get any joy with this course of action, there are renders/paints that claim to be "waterproof" and are supposed to help keep driving rain out. I went with a Sto render on my house which is silicone based. I'm not sure if it helps or not (time will tell) but I know I does appear to repel water somewhat. You can see it bead on the surface a run down the face of the wall. They do offer better more expensive options also. Just a fall back option worth investigating if you don't have any joy.

Calahonda52

Would not recommend any waterproof sealing on the external wall, the wall needs to breath from a vapour diffusion perspective

Thats a big gable so lets ask how it is orientated?

If it is south facing then solar moisture drive, coupled with lots of water getting in via the cracks could be a contributing factor.
some links
http://www.nbec.net/documents/LABORATORYDEMONSTRATIONOFSOLARDRIVENINWARDVAPOURDIFFUSIONINAWALLASSEMBLY-W.MAREF.pdf
http://www.cosella-dorken.com/bvf-ca-es/pdf/articles/Solar-Driven_Moisture_Proceedings.PDF
http://jen.sagepub.com/content/early/2016/01/19/1744259115624183.abstract

While this is normally more discussed in TF construction I am posing it as a possible contributor here.

The beads will not the the carriers of the vapour here, the vapour pressure will just drive the vapour laden air through: the argument thus far has focused on the transfer of water.

Water vapour transfer and water transfer are two entirely different problems.

Just reading the posts here, the legal approach seems to be that they want you to prove that the cracks in the wall and the internal damage are related.
First up, as MT has intimated, that wall is unfit for purpose as is and you may have a structural "failure issue" as opposed to it just being leaky.
So you need to ensure that the gable is structurally sound.

You are going cause and effect here: I am saying wall is structurally unsound so let's boogie on that point as a standalone.

Next up, if the render is not needed for waterproofing, then what did they think its is there for?

What does your engineer say about that.

Thats bXXXXXX

Final question, is the inner leave just skimmed internally in the room on the block, no dry-lining.

Again my instinct is not to open up,
iff, thats if and only if, the wall is structurally sound, I would propose installing a ventilated rain shield over the gable end, its a nice clean area to work on.

For example: rendered, on nylon mesh, concrete board on pressure treated timber battens, ventilated top and bottom and no horz "noggins"

This will solve both the solar drive and water ingress problem and will cost a fraction of the cost of opening up etc, not to mind the legal costs.

This could also be done in conjunction with chemical fixings through the wall to solve the structural issues which made be tie related.

makeorbrake

Calahonda52 wrote: »

Thats a big gable so lets ask how it is orientated?

It's South facing.

Calahonda52 wrote: »

Next up, if the render is not needed for waterproofing, then what did they think its is there for?

What does your engineer say about that.

Thats bXXXXXX

Well, I'm no engineer but that was the first thing I thought of i.e. why the hell bother with an outer leaf then. He's of a mind that its structural and there should be no need to take this step.

I'm only going along with this as I want to nail things down as much as I possibly can - should this go legal.

Calahonda52 wrote: »

Final question, is the inner leave just skimmed internally in the room on the block, no dry-lining.

Yes, skimmed on the block - no dry-lining.

Calahonda52 wrote: »

You are going cause and effect here: I am saying wall is structurally unsound so let's boogie on that point as a standalone.

Yup - that's the second thing I want to prove.

I started out thinking that just a re-render and internal decorate were required. Now, it's looking like a much bigger job.

Hoping to have someone in to open up wall later this week so hope to know more then.

Calahonda52

makeorbrake wrote: »

Well, I'm no engineer but that was the first thing I thought of i.e. why the hell bother with an outer leaf then. He's of a mind that its structural and there should be no need to take this step.

The above makes no sense, I was talking about the render, not the outer leaf.

Anyway my mula is on solar moisture drive.

makeorbrake

Calahonda52 wrote: »

The above makes no sense, I was talking about the render, not the outer leaf.

To clarify, they suggest that the render has no role to play in keeping the dwelling watertight.

Calahonda52 wrote:

Anyway my mula is on solar moisture drive.

It's a new one on me - thanks for the info. Just got back in - will read the info you linked to a little bit later.

PMBC

That's what plastering is for!
Regarding water transfer across snots on ties, surely you would see damp spots at each tie location, if that was the case. Perhaps that's complicated by the use of full fill-insulation.

Calahonda52

makeorbrake wrote: »

To clarify, they suggest that the render has no role to play in keeping the dwelling watertight.

Well then : what is it for?

makeorbrake

Calahonda52 wrote: »

Well then : what is it for?

Good question! I'm just getting the run around - I'll go along with the opening up but ultimately, I'm going to nail them down on this.

Metric Tensor

To be fair an unrendered cavity wall with clean wall ties that have an appropriate drip should be completely rain resistant. "Porous" brick outer leafs have been installed to cavity walls in this context for many years.

1. Problem number 1 is that what we call a cavity wall in many cases no longer has a cavity - it is fully filled with insulation. So if you do, for some reason, have water penetrating the outer block you are relying on the insulation not to transmit the water across. This is specifically considered in the agrement testing for the full fill beads - hence the recommendation regarding driving rain indeces and unrendered walls.

2. I think in many less than well thought out constructions the cementitious render (which does apply some water water-proofing to the wall) is being relied upon for a level of water proofing beyond its "design." I don't think it should not be relied up to do so.

Metric Tensor

To add:

If the moisture you see makeorbrake is definitely coming across the cavity (I'm not fully convinced it is although I don't see an alternative path) then the rainscreen proposed by Calahonda would be the perfect low impact solution.

But I personally would not like to install this without first determining the cause of your horizontal cracks - have they been measured for their width?

PMBC

Metric Tensor wrote: »

To add:

If the moisture you see makeorbrake is definitely coming across the cavity (I'm not fully convinced it is although I don't see an alternative path) then the rainscreen proposed by Calahonda would be the perfect low impact solution.

But I personally would not like to install this without first determining the cause of your horizontal cracks - have they been measured for their width?

good idea, a few crack monitors wouldnt go astray

makeorbrake

Openings have been made. Have not had time to spend any time on this other than a cursory glance - and not going to disturb anything until engineer has a look. However, 2 things confirmed so far - insofar as I can see.

1. Bonded bead being used as cavity infill in an area where all bonded bead Agrement Certs say - ok to use but only with rendered finish (and if the rendered finish is compromised, then it's rational conclusion to arrive at - for me to suggest that's very much an issue and the render by default is responsible for water transfer - or at the least is a component in that process) in areas of severe exposure (which is the case in this instance).

2. One tie exposed thus far - and it shows mortar dabs. See pic below. Bead is particularly wet the touch around this area.


Mortar snot on wall tie.


Will see what the professional evaluation throws up...

Metric Tensor

Finding it hard to figure out what angle I'm looking at there! Do you have any a little more zoomed out for context?

Thanks for posting btw - interesting stuff!

makeorbrake

Metric Tensor wrote: »

Finding it hard to figure out what angle I'm looking at there! Do you have any a little more zoomed out for context!

Apologies - didn't have much time - as had to get back to work. Will post a zoomed out pic tomorrow.

Effectively, that exposed wall tie is at the very edge (above) of the rectangular opening that was cut out. Shows wall tie disappearing into the section of bonded bead infill. I have not exposed it all - will wait for the engineer - but the piece that can be seen has mortar snots on it.

PMBC

Dyu have a moisture meter; presumably your engineer will. Seems to me that the plaster is not impervious and the mortar snots are the path for water transmission.
Great pic, that

makeorbrake

PMBC wrote: »

Dyu have a moisture meter; presumably your engineer will.

Yup, I don't but he will.

PMBC wrote: »

Seems to me that the plaster is not impervious and the mortar snots are the path for water transmission.

I don't want to get ahead of myself but I'm hoping that I already have enough to prove beyond doubt the reason for water ingress.
If Homebond have a responsibility to reinstate, how would you feel about the other walls if it was your house? There's no signs of cracks or internal dampness related to either the back or front walls of the house (it's a semi-d)...although those 2 facades don't take the full brunt of the weather in the same way as the gable wall). Is there any potential that there will be such issues down the road?

A proper inspection has not been carried out on the openings yet. However, the location of the openings was determined purely with the water ingress in mind. I doubt that we will be able to unearth the reason for the horizontal cracks (and proof of same). I guess the only way that can be done is if I open out a section along one of those cracks?

What sort of remedial works would be necessary if for example there was a structural issue due to either improper positioning/application of wall ties or wall tie corrosion? Would it be foolish to assume that the other two walls would not be similarly affected?

Metric Tensor

Remedial wall ties are pretty common and can be installed by drilling in from the outside.

The bigger question is how many existing ties do you have to remove snots from.

I think there's two choices with the other walls:
1. Leave well enough alone.
2. Check some of the ties.

I think if you can get some sort of commitment from HB re discovery of wall tie issues in the front walk in future I'd go for 1. But I'm fairly certain there isn't a hope of getting any commitment!

makeorbrake

Following on from that initial pic, these should give it context as they're zoomed out =>

opening showing exposed wall tie.
Overview of opening.


A second opening was also made;

Second opening
There's a wall tie hanging off the end of that segment of block. There doesn't appear to be any mortar 'snot' on it - but then I don't know if it would have come loose as the outer leaf section was being removed. Then again, the expectation is not that there would be snots on every single tie.

I thought that the area immediately around that first wall tie was wet. However, it seems if I stick a finger through that bead anywhere, the infill is wet.

Metric Tensor wrote:

Remedial wall ties are pretty common and can be installed by drilling in from the outside. The bigger question is how many existing ties do you have to remove snots from.

How will they know where remedial wall ties are needed and where they're not needed? I know the points where the cracks appear may be a no brainer (if its determined that's the actual problem). However, is there a possibility that other points of failure would open at some future point - at which point, I'm s**t out of luck - as I would have to remedy that at my own expense?
How can they determine which ties have snots on them and which have not? Could this be done if the infill was removed?

Metric Tensor wrote:

I think there's two choices with the other walls:
1. Leave well enough alone.
2. Check some of the ties.
I think if you can get some sort of commitment from HB re discovery of wall tie issues in the front walk in future I'd go for 1. But I'm fairly certain there isn't a hope of getting any commitment!

I agree that it's unlikely that they would agree to an arrangement where there wasn't a final settlement - which means that leaving well enough alone is out - so I guess I'll have to open up a couple of sections and check the ties. I suppose I could try with a camera like PMBC suggested but isn't that going to be quite difficult given that the bead is bonded?

Metric Tensor

Great pics!

I'm wary about straying into the field of structural advice here - which is rightly not allowed on this site.

So a few general comments:

1. Great to see the bead is well bonded!
2. Tidy job from whoever did the opening up work.
3. Although the wall might not be "correct" throughout all you can do short of taking down the whole wall is identify the areas that are bad now and deal with them. There is the chance of further failure in future but I don't see anything you can do about it now short of Calahonda's rain screen idea
4. Have Homebond commented?
5. Even if the other side of the bead is wet it may not be wet all the way through. The assumed flow path of water through beads should mean that it gets drier towards the inside with increasing thickness.
6. Are there insulation restraint clips or some other plastic item on the wall ties? It looks a bit like there are but I would not expect to see them.

Edit to say: I'm looking at the pics on a small phone screen. There's people here who are more expert than I in this sort of thing and may correct me.

makeorbrake

Metric Tensor wrote: »

3. Although the wall might not be "correct" throughout all you can do short of taking down the whole wall is identify the areas that are bad now and deal with them. There is the chance of further failure in future but I don't see anything you can do about it now short of Calahonda's rain screen idea

I want to try and avoid being left on the hook due to celtic tiger building practices/lack of oversight. Bought at peak prices with a guarantee on a certain standard so would want to get this resolved completely now (as I'll be on my own hereafter). I'd imagine Calahonda's rain screen would deal with any undetected mortar snots and any lack of integrity of the existing finish. That just leaves any possible structural aspect to deal with (i.e. the root cause of the horizontal cracks and how that can be dealt with - and any potential cracks that have as yet to emerge).

Metric Tensor wrote: »

4. Have Homebond commented?

Hoping to have both engineers on site this coming week.

Metric Tensor wrote: »

5. Even if the other side of the bead is wet it may not be wet all the way through. The assumed flow path of water through beads should mean that it gets drier towards the inside with increasing thickness.

I guess we can determine that by raking back the bead gradually and checking. Cavity seems to be 90-100mm.

Metric Tensor wrote: »

6. Are there insulation restraint clips or some other plastic item on the wall ties? It looks a bit like there are but I would not expect to see them.

There seems to be some sort of black plastic clip in place. Is that to hold the tie in place as the wall is being built - course by course? (it would have been up against the outer leaf).

PMBC

I don't have a great view of that pic - or else its the eyesight going - but it looks to me like an insulation restraint - that's when insulation was just half cavity width.

makeorbrake

PMBC wrote: »

I don't have a great view of that pic - or else its the eyesight going - but it looks to me like an insulation restraint - that's when insulation was just half cavity width.

Apologies - I'd like to provide a clearer pic - but don't want to rake back the bead OR accidentally dislodge the mortar snot on the tie - until such time as both engineers are on site and can see it for themselves.
So that restraint would only be useful where rigid insulation was used?

Metric Tensor

That's what I was thinking. So why is it there? It's not like rigid boards could be installed afterwards! You either need then when you are putting up the wall or you don't need them at all.

Coles

Any update on this? Also any picture to judge the thickness/number of the render layers. It's hard to figure it out from the other pictures. Thanks.

makeorbrake

Coles wrote: »

Any update on this?

The wheels turn slowly, Coles (but I'd prep'ed myself for this eventuality from the very outset so I won't be getting discouraged). I've finally got consensus on a site inspection by the end of the week. The openings will have been 'open' for 2 weeks by then. I'm not sure if that has any significance for any moisture tests that are carried out (we have not had any rain - quite the opposite - and there's been significant 'ventilation' by way of the openings - despite the fact that I've covered them with plywood from the outset).

Looks like Homebond in-house engineer this time rather than one of their outsourced peers. I guess I'm moving up the scale of difficulty in terms of achieving a positive outcome whilst nonetheless making progress!

Coles wrote: »

Also any picture to judge the thickness/number of the render layers. It's hard to figure it out from the other pictures. Thanks.

Pic of side profile of outer leaf. However, it reveals nothing in that respect unfortunately. I'm unsure how I can reveal those layers - as you can see, the builder drilled through at various points to achieve the opening(s)....

makeorbrake

[font=Verdana, sans-serif]Ok, so the update on this is that the other party have finally made a full professional assessment (up until now, they insisted that it was my obligation to prove the precise cause of the water ingress) albeit that I m not privy to the outcome of that assessment (guy under contract so will be reporting back to Homebond). [/font]

[font=Verdana, sans-serif]Removed the bonded bead from the two openings. They had been covered for 14 days - and there had been zero rainfall during this time - blue sky and sunshine. I verified with both engineers that the sections of bonded bead which we cut out were very wet and they acknowledged same.[/font]

[font=Verdana, sans-serif]The area around the wall tie that appeared to have a mortar snot on it was exposed and with that, it was confirmed that the snot extended the full length of the tie from outer leaf surface to inner leaf surface.[/font]

[font=Verdana, sans-serif]My own engineer also expressed the opinion that the angle / bend on the wall ties that we viewed were in such a way as that they were likely to draw water/moisture inwards rather than the other way round.[/font]

[font=Verdana, sans-serif]That's the scenario on the water ingress. It remains to be seen what position Homebond will take on that but I think I have plenty to go on should this have to go further.[/font]


[font=Verdana, sans-serif]With regard to the actual reason for the long lengths and series of horizontal cracks present, I don t seem to be arriving at a definitive finding on that. One theory that was put forward was that the plastering was not all done on the one day and may have been done in sections which *might* lend itself as an explanation as to why horizontal cracks appear at various heights.[/font]



[font=Verdana, sans-serif]Does that last potential explanation sound in any way plausible to any of you? This appears on practically every gable wall in the estate (approx. 30 houses) so would this be likely to happen as a practice throughout? Sounds more plausible to me that maybe it could happen where scaffold wasn t available for some units at the time but not every single house (development was done in 2 stages with the second stage being a couple of months behind the first). IF this was the practice of the plastering crew, then surely the locality should be littered with this type of workmanship? [/font]

Metric Tensor

A stop and restart in applying the render would definitely be a possible cause for a horizontal crack as would a stop and start in blocklaying but I would expect that to give a single crack almost the entire width of the gable.

I personally don't think the multiple, partial-width close cracks that you have would be an indicator of that. They hardly plastered it in 5 attempts!

Was the bead wet all the way through?

Any rust on the tie?

makeorbrake

Metric Tensor wrote: »

A stop and restart in applying the render would definitely be a possible cause for a horizontal crack...but I would expect that to give a single crack almost the entire width of the gable.I personally don't think the multiple, partial-width close cracks that you have would be an indicator of that. They hardly plastered it in 5 attempts!

Those cracks are probably that little bit longer than the initial pic I provided (that pic was submitted in my original application - which would probably be 9+ months ago at this stage. I will take a fresh pic for comparison and post it up tomorrow.
One thing I also brought to their attention yesterday is the existence (on the back wall of the property) now of a consistent hairline crack - again horizontal - between the top window lintels on the first floor - running from window to window - and a second similar crack running at the same point from one of those windows right through to the window in the neighbouring property (its a semi-d). Until now, the focus has been almost entirely on the gable wall.

Metric Tensor wrote: »

as would a stop and start in blocklaying

I guess I understand how this works with render but how would that come about with blocklaying? Differing consistencies in the mortar beds between the blocks?

Metric Tensor wrote: »

Was the bead wet all the way through?

The bead was wet towards the inner leaf end. However, I have to qualify that by saying that the openings had been made 14 days ago. Whilst I had them loosely covered with plywood, they were getting ventilated. When I checked this upon opening the other week, the moisture seemed evident also on the bead surface next to the outer leaf.

Metric Tensor wrote: »

Any rust on the tie?

By the time I got the opportunity to have a proper examination of the wall ties, it was late last night and in bad light. I'll check again but they seemed to be fine in that regard. I guess they're only 10 years in situ so it would be unusual for them to rust through already??

I *think* I can find someone who worked on the development at all stages. Will try and locate him over the course of the weekend and ask him re. how it was rendered/blocked (in fact how they were all rendered / blocked as this manifests itself on practically every gable wall in the estate to some degree or other).

I have to wait for them to come back with their assessment or viewpoint. However, I'd like to reach some firm conclusions myself as to the nature of that cracking. Not sure what the next check/test should be?


PIC's
Section of the bonded bead infill to a depth of 4"
Overview of wall opening with the bead removed and inner leaf exposed

makeorbrake

This was the external gable pic taken 9+ months ago.
And this is it today. That uppermost crack is definitely deteriorating.

New Cracks Emerging - Back wall of the property
All the focus up until now has centred on the gable wall. However, three are new issues emerging of the same nature on the back wall - and vertical cracking on the front wall (perhaps in the case of the front wall, that's something entirely different?).

I had not noticed this until recently => Horizontal crack from 1st floor window to the 1st floor window of the neighbouring semi-d.

Left to Right - from that very same window to the next window along - a horizontal crack running the complete way between the two.

I wouldn't ordinarily report this but in the larger scheme of things, I don't think any cracking is insignificant at this stage => From ground floor kitchen window to oven vent.


New Cracks Emerging - Front Wall of the property

2x Vertical Cracks from 1st Floor bedroom window downwards.

Again, I wouldn't ordinarily report this but for all the other cracking ->
1 x short horizontal crack at the front corner of the front wall of the property

Metric Tensor

Very difficult to comment on this without straying into the area of structural advice which is both against the rules and would be wrong of me to do anyway seeing as I've never laid eyes on your house.

I personally wouldn't be content to blame those cracks on rendering alone without further investigations. So there's a fairly natural next item to check out - although I have no idea how or what exactly you would look at.

makeorbrake

Thanks for your response once again Metric.

I get what you say - and I want to move this item from 'could be this, could be that' to a definitive answer. I have (and i presently am) engaging professional advice on the matter. However, that's not currently leading me to a definitive answer to that question. Therefore, I need to drive this issue myself. I simply don't know specifically what the right way is to go about that...

I guess I could now make an opening specifically in the middle of one of those cracks (neither of the openings were anywhere near said cracks), I could send materials away to be analysed (I'm hoping that's not the issue - as if it was, that could end badly for me ...but then, there don't seem to be enough indicators to suggest that...I *think*...as again, i'm in the dark as not an engineer). Other than that, I'm at a loss.

I'm very grateful to you and to all others here for the suggestions provided to date - it has given me (as an engineering illiterate) at least some understanding of what's pertinent. Are troubleshooting steps in identifying an issue regarded by the forum as structural advice?

Metric Tensor

No - but my thoughts on the matter might be!!

If I was checking one of the cracks I would try picking one away from a window (not the wall plate level one either) and just remove the render first and look at the condition of the blocks and mortar underneath. Then go at it like peeling an onion! A rebound hammer test in the mortar might be nice but results are open to interpretation and may be of no help!

Also if it was me I would treat the roof level crack separately and investigate the tying of the roof to be doubly sure.

All this is going to cost you money that you might never get back though.

As always your engineer knows a lot more about the house than anyone here. Don't do anything without expert advice and oversight and be sure everything you do is structurally sound - i.e. check with your engineer first!!!!

BryanF

makeorbrake wrote: »

Thanks for your response once again Metric.

I get what you say - and I want to move this item from 'could be this, could be that' to a definitive answer. I have (and i presently am) engaging professional advice on the matter. However, that's not currently leading me to a definitive answer to that question. Therefore, I need to drive this issue myself. I simply don't know specifically what the right way is to go about that...

I guess I could now make an opening specifically in the middle of one of those cracks (neither of the openings were anywhere near said cracks), I could send materials away to be analysed (I'm hoping that's not the issue - as if it was, that could end badly for me ...but then, there don't seem to be enough indicators to suggest that...I *think*...as again, i'm in the dark as not an engineer). Other than that, I'm at a loss.

I'm very grateful to you and to all others here for the suggestions provided to date - it has given me (as an engineering illiterate) at least some understanding of what's pertinent. Are troubleshooting steps in identifying an issue regarded by the forum as structural advice?

Have you/could you inspect some of your neighbours properties? For similar..