cracks in old boundary wall

Piriz · 31-07-2020 5:19pm #1

My wall separates my garden from a public path/road. The wall is about 6.5foot high, its built from concrete and <1inch stones. I'd say it could be 100 years old. There is a number of horizontal cracks visible both sides of the wall in parts. The wall is perfectly upright, the pebble dash has come away from the wall, the remaining pebble dash would be easy to remove. A good bit further down the same wall has a significant vertical crack top to bottom..(this is at my neighbours side) however the wall is still perfectly upright neighbours end too.

see photo attached.

any advice what the best thing to do is?

thanks..

Stanford · 31-07-2020 5:22pm

Get advice from a good Mason

Piriz · 31-07-2020 5:24pm

Stanford wrote: »

Get advice from a good Mason

hopefully one on here..

Stanford · 31-07-2020 5:27pm

If the vertical crack runs all the wall down the wall then it needs repairing, old walls can sometimes be strengthened with metal plates which straddle the crack

looksee · 31-07-2020 5:38pm

If you feel the wall may not be safe get an engineer to look at it. It doesn't look as though it is going anywhere from here, but photos are no substitute for professional examination.

Then decide what you are looking for. It does depend on the look of the house and whether it is rural or urban, and how much there is of it.

Do you want a nice shiny new wall look? In that case strip the pebbledash, re-dash and paint or face (ugh) or whatever you fancy. Or accept that it is 100 years old and looking a little venerable. Just paint it. If the dash is loose you could knock off the dodgy bits and re-dash the patches, or just paint over the gaps (which is probably what I would do, but not everyone likes the 'comfortable, lived in look). Or just leave it.

Piriz · 31-07-2020 5:44pm

the vertical crack is about 5 meters past where my boundary ends.. my neighbour recently had the wall heightened by about one meter with decking timber running horizontally fixed with 2x4 batons.. he said the guy who did the job for him commented the wall is grand but I'm not convinced.. the cracks will get worse and the heightened wall will face more force during storms and strong winds.. (bearing in mind we had about four storms last year or two).

I'm interested in heightening the wall with timber the same way as my neighbour but I want to make sure the wall is sound first..

Calahonda52 · 31-07-2020 5:48pm

One common solution here is to bury some decent sized steel channel [150 by 90 or so] in the ground right again the wall, down as far as the foundation and bolt the channel to the wall all the way up having predrilled the steel.

If the foundation is near the surface you may need to come out and make up the difference
May not be the prettiest but it works.
What with is the wall?

Metric Tensor · 31-07-2020 5:56pm

Those "cracks" looks unusual but very difficult to tell much about it from the photo.

Any chance of an close up of each of the cracks and also the opposite side of the wall in the same location.

Whilst you're at it take a walk down the road and snap your neighbours vertical crack too.*

(Yes - I am aware what the sentence sounds like and did it on purpose!!!!

)

Piriz · 31-07-2020 6:55pm

the wall is 20cm width (including pebble dash on one side)

I think the wall was built in three horizontal sections.. in this photo you can see two horizontal lines (cracks) the lower one much is less visible..

this is pretty much the full span of the wall.. it's about 15 meters

Piriz · 31-07-2020 6:59pm

this is my neighbours vertical crack,

Piriz · 31-07-2020 7:00pm

close up of one horizontal crack on my side..doesn't look too bad

Piriz · 31-07-2020 7:06pm

this is a photo of a different boundary wall.. (runs perpendicular to the other wall but not connected) probably built the same time. this wall has no pebble dash.. you can see horizontal lines how it was built..this wall is in good shape

Tails142 · 31-07-2020 7:09pm

The horizontal crack looks to me like the concrete was poured in two lifts so there is a seperation there between to the two pours of concrete. This has also caused moisture to get in behind the dash and spall probably through freeze thaw or just shrinkage and expansion in heat.

Wall looks fine to me.

I have seen walls get blown over when they have timber attached to the top like that, it can be a gamble and depends how exposed the area is but probably works out fine 99% of the time.

If you ran timber battens vertically down the height of the wall it can only help with the horizontal cracking

mickdw · 31-07-2020 7:10pm

Yes the horizontal joints very much appear to be construction joints.
We cannot give structural advice here so best get it looked at but i dont see any obvious movement in the photographed section.
In the ground either side of the wall at the same level?

Private Joker · 31-07-2020 7:14pm

mickdw wrote: »

Yes the horizontal joints very much appear to be construction joints.
We cannot give structural advice here so best get it looked at but i dont see any obvious movement in the photographed section.
In the ground either side of the wall at the same level?

I'd agree. It seems that the esb carried out works recently where that vertical cracks is. Might ask esb engineers to have a look at it.

Metric Tensor · 31-07-2020 7:29pm

As above OP - the reason I put "crack" in quotation marks is because I thought they were construction joints rather than newly formed cracks. No-one here can say based on photos that the wall is fine but it does appear those horizontal discontinuities are not recent. No harm getting someone to look at it all the same - the potential changes brought about by the render falling off need to be thought about anyway.

The vertical crack is definitely a crack and should be investigated.

Piriz · 31-07-2020 7:33pm

Tails142 wrote: »

The horizontal crack looks to me like the concrete was poured in two lifts so there is a seperation there between to the two pours of concrete. This has also caused moisture to get in behind the dash and spall probably through freeze thaw or just shrinkage and expansion in heat.

Wall looks fine to me.

I have seen walls get blown over when they have timber attached to the top like that, it can be a gamble and depends how exposed the area is but probably works out fine 99% of the time.

If you ran timber battens vertically down the height of the wall it can only help with the horizontal cracking

I wonder if I should patch up the dash as a partial solution? or should I remove all the dash and redash the entire wall..? or at least my side of it.

the wall runs north to south so receives a lot of wind going from west to east. the opposite side of the wall has a buttress about every two meters which is good.. if I heightened the wall the same way as my neighbour I guess I could fix the batons to the lower half of the wall and then the wind wouldn't provide force to the upper part of the wall (if that makes sense)

Piriz · 31-07-2020 7:35pm

mickdw wrote: »

Yes the horizontal joints very much appear to be construction joints.
We cannot give structural advice here so best get it looked at but i dont see any obvious movement in the photographed section.
In the ground either side of the wall at the same level?

yea the ground is pretty much level either side

Piriz · 31-07-2020 7:37pm

Private Joker wrote: »

I'd agree. It seems that the esb carried out works recently where that vertical cracks is. Might ask esb engineers to have a look at it.

that's an idea.. concern that the ESB see an issue and request my neighbour repair it and he gets the hump with me for bringing it to their attention (maybe a topic for the Personal Issues forum)

thanks for all the replies

Calahonda52 · 31-07-2020 8:25pm

Its p[ossible that the wind load on the timber fence has had something to do with it.
I would leave the esb out of it for the reasons you mention.

Piriz · 31-07-2020 8:51pm

Calahonda52 wrote: »

Its p[ossible that the wind load on the timber fence has had something to do with it.
I would leave the esb out of it for the reasons you mention.

the timber fence is new.. about two weeks old

Lumen · 01-08-2020 6:39pm

Piriz wrote: »

if I heightened the wall the same way as my neighbour I guess I could fix the batons to the lower half of the wall and then the wind wouldn't provide force to the upper part of the wall (if that makes sense)

The torque at the base of the wall will be the same regardless.

How high is the wall now? What height are you propsing to raise it to?

Piriz · 01-08-2020 6:58pm

Lumen wrote: »

The torque at the base of the wall will be the same regardless.

How high is the wall now? What height are you propsing to raise it to?

interesting comment about the torque.. if the fence is fixed to the lower half of the wall this half is much less vulnerable to fall over therefore better than fixing to the top of the wall I thought... but I think I understand your point.. thanks

also the neighbours fence is built with decking boards going horizontally with about 15mm space between each row.. this might reduce the force slightly (maybe not).

the wall is just under 7 foot, I'd raise it by another 3 foot (as my neighbour did).

Lumen · 01-08-2020 9:46pm

Piriz wrote: »

the wall is just under 7 foot, I'd raise it by another 3 foot (as my neighbour did).

I believe that this requires planning permission, as did your neighbour's modifications.

The few walls I've seen fallen over from wind have fallen over at the base, not half way up, so I think that your proposal to secure the fencing lower down the wall is not an improvement.

Safehands · 04-08-2020 11:40am

Piriz wrote: »

I wonder if I should patch up the dash as a partial solution? or should I remove all the dash and redash the entire wall..? or at least my side of it.

the wall runs north to south so receives a lot of wind going from west to east. the opposite side of the wall has a buttress about every two meters which is good.. if I heightened the wall the same way as my neighbour I guess I could fix the batons to the lower half of the wall and then the wind wouldn't provide force to the upper part of the wall (if that makes sense)

The concrete does not look that strong, from looking at the the photos. Is there any reinforcing in it? It does not look like there is. Perhaps you could "stitch" it with reinforcing bars across the cracks. That involves cutting a chase across the crack and inserting steel bars, preferably stainless, and securing them with a resin anchor grout.
Best advice though: Get an engineer's opinion. All the advice here is useful, but you need to talk to an engineer before you proceed with anything.

Piriz · 08-08-2020 8:31am

Safehands wrote: »

The concrete does not look that strong, from looking at the the photos. Is there any reinforcing in it? It does not look like there is. Perhaps you could "stitch" it with reinforcing bars across the cracks. That involves cutting a chase across the crack and inserting steel bars, preferably stainless, and securing them with a resin anchor grout.
Best advice though: Get an engineer's opinion. All the advice here is useful, but you need to talk to an engineer before you proceed with anything.

is it a structural engineer I need to speak to? or a home survey type engineer?

hopefully wont be too expensive

cracks in old boundary wall

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