external insulation

duckcfc

I've a 2000sq ft dormer bungalow, south facing built about 10 year ago on the cheap but now I'm looking to do a few upgrades and starting with external insulation so I've a few questions.

I'm near sure my over hang is about 9 inches or there abouts and is it possible to bring the insulation flush with over hang or will I have to keep it back abit from the fasica board.

I have concrete window cills and quite large windows. Will I have to remove and replace new cills and can I move the window to the outer block for more light to get in instead of it sitting back from face of insulation.

Does anyone have a rough idea of costs it is just for materials seeing as I'm going to install it myself( Im a builder/handyman and was also plastering for few years)

What about my downpipes, will I have to move these and move my soil pipes/ajs because if I install 200mm insulation, it'll cover my them for future inspections.

I'm also wanting to face my house in natural stone, if I do this, is it possible to work up to insulation where it'll overhang both sides if the house what ever thickness insulation is. At front of house I'll put in internal insulation/plasterboard for the extra insulation in place of external seeing as I can't tie in the stone to it.

cerastes

Interested to hear how this goes, have you got any calculations done? So you are not putting too much up? I'd have thought most installations of external insulation would be coming in at a similar thickness given there isn't significant variability in temps across the country and construction is generally similar.
I've no idea what thickness is generally put up, but I'd have thought the product is made in standard thicknesses? 200mm sounds like a lot but that might be the norm, there must be a point above which the returns on the cost of the insulation won't be recovered, and the practicality of fitting above a certain thickness.
I googled a few websites for EWI to see what products there were, they have different kinds of plastic plugs which support the mushroom headed screws and heavier duty ones for supporting mounting points for drains.

I'd looked at it to see what the costs of doing it myself might be, big enough job but possible I think, the plastering/rendering would have to be done by someone else, I never worked out the cost, so can't say what saving there might be.
Im sure they have moulded plastic pieces to cover and mimick cills.

I think its a big job to do alone but not impossible, certainly easier with a helper.
I think making sure there is enough space for ventilation at the soffit into the attic, maybe even a continuous vent covered if its narrow.

PROJECT K

Hi duckcfc,
A few points you will need to consider:
1. You should be aiming to achieve a certain U-Value (i would suggest minimum 0.27 but strongly recommend heading towards 0.15 or better)
2. No.1 will influence thickness and type of insulation - you could use 200mm of white EPS or 100mm of Phenolic foam to achieve the same U-Value (approx) - make sure you dont block existing eaves ventilation on the soffit! (this spec should get you around 0.15-0.16W/m2.K u-value depending on overall construction)
3. External Insulation will need to connect to your roof insulation to prevent a significant thermal bridge (this means removal of the soffit board is a requirement)
4. Concrete sills no prob - cut them off flush with the existing wall and provide new insulated sills as part of the EWI installation
5. SVP, RW goods etc - need to be relocated ouitside of the insulation layer (otherwise huge thermal bridge and not practical to maintain etc)
6. Make no mistake, this is not a job for a "handyman" or general plasterer (no disrespect but this is a specialised application and you will need the warranty from the system provider). Polymer modified renders are difficult to apply correctly and i have seen numerous projects where even registered installers get it wrong...issues vary from excessive discolouration, poor adhesion/boasting, and insufficient depth of render
7. Stone isnt really an option with EWI, it can be done but i certainly wouldnt recommend it - go with a nice clean modern white rendered facade and you will never tire of the appearance!
8. As a budget price, EWI can cost anything from €80 to €130 per sqm of gross facade area - depends on complexity of the building and final specification. PM me if you want my recommendations (not affiliated to any EWI company/system but learned from experience in the industry!)

Hope this helps, good luck with the project!

Regards
PK

cerastes

Does the soffit have to be removed?
I thought this might cause other problems? aside from how it might look, couldnt the EWI be in direct contact or sealed to the soffit? and insulation on the other side bonded to the soffit. Any cross sectional drawings I have seen have always shown some form of soffit board.

Whats the specialised training or experience required for rendering this? presumably existing plasterers are the ones going forward to do the job? Does this come from the companies that do it? and where do they get the specialised training when they are only starting themselves? from the point of view of picking an organisation to do it? and ensuring they are experienced enough.

PROJECT K

sorry may not have been clear here - it needs to be removed to ensure EWI meets the attic/roof insulation, its replaced once the EWI work is complete (reduced width obviously). You will need to form a new soffit support, typically hung from rafters. Its unlikely you will have access to the eaves to insulate this properly without taking the soffit off...

PROJECT K

Training and accreditation is provided by the system suppliers for example Parex, Weber, Sto etc etc - yes it typically is plasterers that do this work but its a slightly different process than standard sand/cement. It is possible to take this on as a DIY project but you will struggle to get the materials from reputable suppliers (they dont want the bad publicity if something goes wrong!). While i mentioned warranty above, i have heard that when things do go wrong the system suppliers will blame aliens from outer space quicker than accept responsibility!!! ultimately you are very reliant on the tradesperson you employ and always check with their previous work and clients...

Calahonda52

Agree with PK re the project risks for a DIY project as well as the technical details.
In case you get different advice, don't even think about not moving the sewer pipes and downpipes

What might be worth exploring is using a wood fibre product and putting on an external rain screen using cement board which does not have the same problem with the plaster finish.
There are different variations of this method, one I have seen had a treated timber frame structure outside the wood fibre with the cement board screwed with stainless steel screws to the frame
.Just a thought

cerastes

Out of interest (not that Ive funds to even do this myself let alone pay someone),
The foul water drain connects into the ground from a side wall at my house, but its right beside the external wall, obviously the foul water pipe would be moved to over any EWI, but it looks like it would be an inconvenient task to replace the connection point of the pipe, if ever I was getting it done I considered that a cut would have to be made to the EWI and the pipe angled back in, it would be a tiny percent of the overall external surface not insulated and could be filled or covered.
It might not seem ideal for maintenance, but given no maintenance has ever been required up to this point it seems unlikely it ever would.

Its the same for the one gutter drain, but that seems an easier prospect to fill in and move slightly further out.

Calahonda52

Can u post a pic pls

Where the sewer pipe actually enters the stack is key.

Also in most retro EWI, it changes thickness where the existing DPC layer is in the wall

cerastes

Calahonda52 wrote: »

Can u post a pic pls

Where the sewer pipe actually enters the stack is key.

Also in most retro EWI, it changes thickness where the existing DPC layer is in the wall

Me?
its between two locked gates, the pipe goes into the ground, if I recal correctly, I think it seems to go into a fitting which is embedded in the concrete on the ground.
My concern with redoing this below the surface is that its functional now and breaking it and burying it means you cant confirm its starts leaking after its been filled over.

I looked over a few clips where manufactuers where showing fitting their product, and as much as they make it look easy to fit the insulation layer, they showed two methods of adhering the EWI onto the existing structure, one was with dabs of standard method mixed out of bags and the other was more like a foam/glue out of tubes, after that they drilled holes put supporting blocks into the holes and tapped mushroom headed screws into drilled holes. Im sure its not completely as straight forward as that, I still think its possible, I mean, how can you confirm a fitter has specific training? or enough experience? you'd need to see a job that was up years to confirm it was long lasting surely?
The rendering over the EWI would be a different matter I think, requiring maybe specific expertise?

Its possible a good job is possible by someone used to doing DIY stuff themselves, compared to a bad job lashed up by someone in a hurry even if they are experienced.
All in its a big job and likely too much for most people even with experience to take on, and still do anything else they have to do.

Calahonda52

No not you!, the OP for pics

duckcfc

PROJECT K wrote: »

Hi duckcfc,
A few points you will need to consider:
1. You should be aiming to achieve a certain U-Value (i would suggest minimum 0.27 but strongly recommend heading towards 0.15 or better)
2. No.1 will influence thickness and type of insulation - you could use 200mm of white EPS or 100mm of Phenolic foam to achieve the same U-Value (approx) - make sure you dont block existing eaves ventilation on the soffit! (this spec should get you around 0.15-0.16W/m2.K u-value depending on overall construction)
3. External Insulation will need to connect to your roof insulation to prevent a significant thermal bridge (this means removal of the soffit board is a requirement)
4. Concrete sills no prob - cut them off flush with the existing wall and provide new insulated sills as part of the EWI installation
5. SVP, RW goods etc - need to be relocated ouitside of the insulation layer (otherwise huge thermal bridge and not practical to maintain etc)
6. Make no mistake, this is not a job for a "handyman" or general plasterer (no disrespect but this is a specialised application and you will need the warranty from the system provider). Polymer modified renders are difficult to apply correctly and i have seen numerous projects where even registered installers get it wrong...issues vary from excessive discolouration, poor adhesion/boasting, and insufficient depth of render
7. Stone isnt really an option with EWI, it can be done but i certainly wouldnt recommend it - go with a nice clean modern white rendered facade and you will never tire of the appearance!
8. As a budget price, EWI can cost anything from €80 to €130 per sqm of gross facade area - depends on complexity of the building and final specification. PM me if you want my recommendations (not affiliated to any EWI company/system but learned from experience in the industry!)

Hope this helps, good luck with the project!

Regards
PK

No1- does a Ber assessor do this for me.
No2. Foam sounds good because thinner but how much difference in cost. Is it just a matter off screwing xtratherm onto exterior wall.
No3. I have glass roll fibre insulation above void above ceiling and upright then xtratherm in slope of roof. I was going to upgrade with silver roll of insulation. Can I just roll it on out over wall plate and on top of new external insulation.
No4. Are new cills expensive.
No5.?
No6. This job will be getting done by me! I'll take few weeks off in summer and do it then.
No7. I want my front of house done in stone, I won't compromise on this so there will have to be away around it.
No8. Is that to include labour costs? Seems high if just materials. Please send on recommendations.

duckcfc

Calahonda52 wrote: »

Can u post a pic pls

Where the sewer pipe actually enters the stack is key.

Also in most retro EWI, it changes thickness where the existing DPC layer is in the wall

The ajs won't be a problem, its the downpipes but can Im sure they could be covered in insulation.

Calahonda52

duckcfc wrote: »

I've a 2000sq ft dormer bungalow, south facing built about 10 year ago on the cheap but now I'm looking to do a few upgrades....

But still on the cheap based opost.r post 12 and in ur 13 post you are not reading whats been written

3 walled ewi creates a mad thermal bridge.
There is a grant for full 4 wall

PROJECT K

duckcfc wrote: »

No1- does a Ber assessor do this for me.
No2. Foam sounds good because thinner but how much difference in cost. Is it just a matter off screwing xtratherm onto exterior wall.
No3. I have glass roll fibre insulation above void above ceiling and upright then xtratherm in slope of roof. I was going to upgrade with silver roll of insulation. Can I just roll it on out over wall plate and on top of new external insulation.
No4. Are new cills expensive.
No5.?
No6. This job will be getting done by me! I'll take few weeks off in summer and do it then.
No7. I want my front of house done in stone, I won't compromise on this so there will have to be away around it.
No8. Is that to include labour costs? Seems high if just materials. Please send on recommendations.

Ber assessor, insulation supplier, professional consultant etc etc - its a fairly simple calc

Xtratherm don't do phenolic, Kingspan do...the insulation is normally fully bonded or partially with additional fixings (normally 5 no. Per 1.2x0.6m board). Typically a non faced (eps, woodfibre, Rockwool) or non foil faced board (phenolic) is used

Presume you are referring to multi-foil insulation - this requires an enclosed airspace on at least one side (two sides to be most effective) - not really possible for the application you describe. Suggest you either use fibrous roll of insulation or rigid foam board - making sure to leave min. 50mm air gap to felt

? - soil vent pipe and rainwater goods, these need to be taken off and relocated to the outside of the external insulation and render

Sills can either be moulded xps or eps insulation or pressed powdercoated aluminium - shouldn't be too expensive in the grand scheme of things

Good luck going DIY with this, not recommended!

Only practical way is to internally dryline, pump cavity or leave as is - then you can put stone on if you want (but be very careful where pumped cavity or dryline meets EWI - you will need to overlap by absolutely minimum 500mm to minimse thermal bridge - terrible detail but i dont see any alternatives)

Price is a guideline system price for the complete project, removal/reinstatement of rw goods, sills etc

You mentioned in your original post that you did the house on the cheap and now you run the risk of an inferior thermal upgrade on the cheap. Problem is that an extensive upgrade like this can cause more problems than it solves - thermal bridging and associated condensation risk,water ingress, structural decay etc. Get a professional involved before you commit to anything and get a detailed specification & set of details drawn up.

Your house your choice, I guess from your post your minds made up - I have just seen this so many times its frustrating so forgive my lecturing!!!

MicktheMan

duckcfc wrote: »

I've a 2000sq ft dormer bungalow,...

You sure ewi will be of any benefit?

duckcfc

MicktheMan wrote: »

You sure ewi will be of any benefit?

Why's that? I'll also be upgrading my insulation in loft/void areas and already have 100mm extratherm in my slopes. I'm sure it should keep my house nice and warm these upgrades.

duckcfc

PROJECT K wrote: »

Ber assessor, insulation supplier, professional consultant etc etc - its a fairly simple calc

Xtratherm don't do phenolic, Kingspan do...the insulation is normally fully bonded or partially with additional fixings (normally 5 no. Per 1.2x0.6m board). Typically a non faced (eps, woodfibre, Rockwool) or non foil faced board (phenolic) is used

Presume you are referring to multi-foil insulation - this requires an enclosed airspace on at least one side (two sides to be most effective) - not really possible for the application you describe. Suggest you either use fibrous roll of insulation or rigid foam board - making sure to leave min. 50mm air gap to felt

? - soil vent pipe and rainwater goods, these need to be taken off and relocated to the outside of the external insulation and render

Sills can either be moulded xps or eps insulation or pressed powdercoated aluminium - shouldn't be too expensive in the grand scheme of things

Good luck going DIY with this, not recommended!

Only practical way is to internally dryline, pump cavity or leave as is - then you can put stone on if you want (but be very careful where pumped cavity or dryline meets EWI - you will need to overlap by absolutely minimum 500mm to minimse thermal bridge - terrible detail but i dont see any alternatives)

Price is a guideline system price for the complete project, removal/reinstatement of rw goods, sills etc

You mentioned in your original post that you did the house on the cheap and now you run the risk of an inferior thermal upgrade on the cheap. Problem is that an extensive upgrade like this can cause more problems than it solves - thermal bridging and associated condensation risk,water ingress, structural decay etc. Get a professional involved before you commit to anything and get a detailed specification & set of details drawn up.

Your house your choice, I guess from your post your minds made up - I have just seen this so many times its frustrating so forgive my lecturing!!!

Is there anywhere that does courses on the external insulation, how to apply it etc...

MicktheMan

duckcfc wrote: »

Why's that? I'll also be upgrading my insulation in loft/void areas and already have 100mm extratherm in my slopes. I'm sure it should keep my house nice and warm these upgrades.

Your house is a dormer. It is well known that dormers perform extremely poorly for air tightness unless specific actions were taken when building to air tighten the envelope. Insulation does not address air tightness so even though you plan on upgrading the insulation, this may well have little impact on keeping your house "nice and warm".

The best advice I can give you is to have your house tested for air tightness and then decide on how best to proceed.

duckcfc

Listen, I know I need my house air tight for it to be really efficient but there's not a chance if I add all this insulation that the house won't be warmer. Its not all about just making sure its airtight, yes it might in them books most you study from but in the real world, more insulation will make my house more warm. Maybe in another few years after upgrading insulation I'll make my house airtight.

As for adding more insulation, let me give an example of how just a little but of insulation can make a difference. I keep bees and in the roof of the hive, we add 25mm of xtratherm and even thou all walls have no insulation, it makes a difference and that's with an open floor!

MicktheMan

duckcfc wrote: »

...but in the real world...

In the real world, I test houses for heat loss mechanisms. Very, very, very rarely the cause of heat loss / discomfort is due to lack of insulation. In the vast majority of cases air leakage is the culprit and this is true in nearly 100% of dormer houses (even though the home owner may have carried out various insulation upgrades to try to address the issues).

Yes, insulation has its role to play and nobody is saying otherwise. But if you ignore air tightness in a dormer, you will not gain much of the insulation benefit.

Good luck with whatever you decide.:)

cerastes

Calahonda52 wrote: »

Starting at the outside, can you list the layers and thicknesses of all the materials in your slope after the 100mm has been added

To get you started:
Roofing material: slates, concrete tiles, corrugated sheeting, or whatever
Slating lathes: 25 by 50
.
.
Plasterboard gypsum skin

On the increased insulation in the loft areas unless its airtight then the wind passing through it will negate the benefit to a certain degree: if its badly fitted then maybe 100% negation

I'm not sure about air tightness, its hardly wind blowing through any areas of leakage other than vents standard inmost Irish homes, in that case mhvr would do more for heat lost than airtightness, couldnt that mean an equivalent or similar amount of heat is lost prior to upgrading insulation as afterwards from airtightness in other ways? Airtightness might mean upgrading doors, windows the cost of which is never recovered for energy saving purposes from what I've read, aside from the costs of implementing a whole house airtightness? Not sure how that is done? Membranes? But retrofitting that in an existing house can't be easy, maybe even possible and seems could be prohibitively expensive if not completely impractical.

As much as I'd have concern about installers that just fit ewi without an assessment or at least a detailed one with energy savings determined, even without determining what the improvement or saving is, its still got to be better at retaining heat than not having it,
House I grew up in didn't have insulation, years later it was dry lined inside bit by bit, some rooms with insulation and better than other rooms, the difference between unlined rooms and lined was huge, cold walls compared to not, this was a house with wooden framed leaky windows.
I can't see how any improvement can be seen as not effective due to airtightness not implemented.
As much as I'd be interested in ewi, blocking up the gaping vent holes would be a big concern and replacing ventilation with something else.

Calahonda52

The issue here is that throwing loads of extra insulation into a house , without considering heat lost through uncontrolled ventilation is false economy.

Simple analogy:
windy day: you put on the aran sweater, the one with the nice herring bone design al a Clancy Bro
You go out the door, wind goes through the sweater and you run back and get the plastic rain coat and put it over the aran.
You come back from your exertions and the inside of the jacket is damp with sweat.
Next time you put on the Gore Tex Jacket
Gore Tex is a trademark for a water-repellant, breathable laminated fabric.

This document http://www.standards.ie/cgi-bin/news/ie/NEW276
at 13 Mb is not small but very readable and pertinent

cerastes

I see what you're saying, but aside from the large square vent hole in the corner of the room common to most Irish houses, how leaky are most houses? I'm sure they aren't perfect but its hardly a gale blowing through?
Are you just talking about air tightening the attic space where the former is?
Or the whole house? How practical is that to do in an existing build, seems the cost of the work could make it too much for most to consider and likely makes a big impact on any savings made if there is any left after the kind of work to make an existing build compliant.

PROJECT K

this is my point re getting professionals involved - an extensive thermal upgrade like this needs to be an holistic approach, its madness sorting out the insulation now and leaving the airtightness to later. This must all be planned and executed together to be most cost effective and beneficial (and least disruptive in the long term). Every house is different and the surrounding topography etc will have a huge impact on issues related to poor airtightness. In some cases insulation will sustantially solve the problem on its own, in other cases ensuring airtightness can have a monumental impact but for the vast majority it takes both to realise the best performance

in relation to training, you could apply to be a registered installer for one of the system providers and then they will provide training (usually free)

duckcfc

Calahonda52 wrote: »

The issue here is that throwing loads of extra insulation into a house , without considering heat lost through uncontrolled ventilation is false economy.

Simple analogy:
windy day: you put on the aran sweater, the one with the nice herring bone design al a Clancy Bro
You go out the door, wind goes through the sweater and you run back and get the plastic rain coat and put it over the aran.
You come back from your exertions and the inside of the jacket is damp with sweat.
Next time you put on the Gore Tex Jacket
Gore Tex is a trademark for a water-repellant, breathable laminated fabric.

This document http://www.standards.ie/cgi-bin/news/ie/NEW276
at 13 Mb is not small but very readable and pertinent

You are comparing apples and oranges, a person wearing a jumper and a house are 2 totally different things altogether.

duckcfc

PROJECT K wrote: »

this is my point re getting professionals involved - an extensive thermal upgrade like this needs to be an holistic approach, its madness sorting out the insulation now and leaving the airtightness to later. This must all be planned and executed together to be most cost effective and beneficial (and least disruptive in the long term). Every house is different and the surrounding topography etc will have a huge impact on issues related to poor airtightness. In some cases insulation will sustantially solve the problem on its own, in other cases ensuring airtightness can have a monumental impact but for the vast majority it takes both to realise the best performance

in relation to training, you could apply to be a registered installer for one of the system providers and then they will provide training (usually free)

Any links for these providers?

PROJECT K

duckcfc wrote: »

Any links for these providers?

Sorry not to hand, a quick google search should work...

duckcfc

Anyone know what is the criteria for getting a grant for this and what's the average one gets after applying

BryanF

duckcfc wrote: »

Anyone know what is the criteria for getting a grant for this and what's the average one gets after applying

Google
Seai Grants

duckcfc

BryanF wrote: »

Google
Seai Grants

It doesn't mention if ive to pay first and claim back the money or the contractor gets paid. Another thing, it says houses built prior to 2006, I started mine in 2004 but wasn't fully completed until 2008 thou I was living in it from 2005 onwards. Would I qualify?

BryanF

duckcfc wrote: »

It doesn't mention if ive to pay first and claim back the money or the contractor gets paid. Another thing, it says houses built prior to 2006, I started mine in 2004 but wasn't fully completed until 2008 thou I was living in it from 2005 onwards. Would I qualify?

youve answered your own question.

duckcfc

BryanF wrote: »

youve answered your own question.

What one, there's a few