Possibly a bonkers idea - cavity wall insulation

cojmh
Posts: 218
Joined: Wed Mar 16, 2022 8:11 pm
Location: West Midlands

Re: Possibly a bonkers idea - cavity wall insulation

#61

Post by cojmh »

Richard77 wrote: Fri Oct 18, 2024 11:28 pm Hope everything goes well mate... Will be keeping a keen eye on this thread to see how it goes due to my own gable issues!

House had quite a bit of movement in the 90's and had some remedial work done on it. A bit of underpinning, etc.

We bought it in 2015 and it had quite significant bulging on the gable wall and several places of cracking. It hasn't gotten any worse since the 90's apparently and structural engineer said it is historical movement.

We got the whole of the house externally piled when we bought it and had to go down approximate 8 metres to find solid ground. Done this as a precaution. We have seen no difference in the wall(s) for the 9 years we have owned it, so it seems ok (fingers crossed).

We are a looking to get rid of the bulging brickwork though as it is quite an eye sore. I don't know whether it's the subsidence or wall tie failure or both. It isn't getting any worse though so that's a good sign. It is a bit daunting when thinking about knocking down some or all the wall and rebuilding. I am a bit wary to get anything done to it in case the worst happens and it all falls down like a pack of cards!
We bought this house in 1995 too ..... will be a road to get it to where we want .... but well on the way!

Do you know what caused the movement in your case? I assume unstable ground rather than something like trees etc.

Where abouts is the bulge in the wall and is it a significant area - or can you just tidy up a bit of the wall to make it look good?
cojmh
Posts: 218
Joined: Wed Mar 16, 2022 8:11 pm
Location: West Midlands

Re: Possibly a bonkers idea - cavity wall insulation

#62

Post by cojmh »

spread-tee wrote: Sat Oct 19, 2024 8:39 am Forgive me for the silly question, but why start dismantling the wall from the bottom? I did something similar a while back on a smaller scale to be fair and we took it all down from the top, no propping needed. I take it your house is standard construction, IE the inner leaf is the load bearing element. Does he want you to re-build it from the top down?? :D High water table is a right pain in the arse , don't tell me you are on clay too? Heavy shit!

Desp
I don't fully know the reason for that - but the structural engineer was immediate and adamant in his response of "NO!" when it was suggested.

The house is of traditional construction with the inner course being load bearing but here a few facts that might have affected the decision the structural engineer made.

1. We were and are currently living in the house ( :( ) so there was no scope for supports being placed inside the house.
2. The floor joists run into and are support by this gable end wall.
3. The original owners (who it would seem are penny pinching to the extreme) decided to build around the existing single garage that formed half of the ground area of the extension. In my opinion it would have made more sense to knock it down and start again but considering the gas main and electric main both came into the garage and were mounted on the walls this might have been the reason they chose not to. I have moved both in this current works.

Once we get higher up and I show you some of the quality of the inner course work - I think this piece meal approach might have been a prudent approach.

I think we have really gone belts and braces with our approach and it has definitely added quite a bit of time and expense .... but a lot less than a failure of the inner course of blockwork .... or at least that is how I have rationalised it to myself.
cojmh
Posts: 218
Joined: Wed Mar 16, 2022 8:11 pm
Location: West Midlands

Re: Possibly a bonkers idea - cavity wall insulation

#63

Post by cojmh »

Oh yeah .... and we are on a very dense layer of clay that starts just below the surface .... yay!
Richard77
Posts: 62
Joined: Thu Sep 19, 2024 3:26 pm

Re: Possibly a bonkers idea - cavity wall insulation

#64

Post by Richard77 »

cojmh wrote: Sat Oct 19, 2024 9:27 am
We bought this house in 1995 too ..... will be a road to get it to where we want .... but well on the way!

Do you know what caused the movement in your case? I assume unstable ground rather than something like trees etc.

Where abouts is the bulge in the wall and is it a significant area - or can you just tidy up a bit of the wall to make it look good?
The whole area used to be a lake 100's of years ago apparently and the water table is high.

Before we got it piled I dug a few test holes around the foundations and at about a depth of 6ft water started to come up.

On the original borehole log the first few metres were "very loose brown silty sand" then from 4 metres down "firm becoming stiff brown slightly sandy silty clay with occasional sand lenses". Was like that for 10 metres.

The house is a semi detached and next door seemed to have had a lot of issues we have had with internal and external cracking. They don't have any bulge in the brickwork though (that's why I assume that's the result of wall tie failure as well as the movement?). They had a structural survey done a while ago and they blamed the drains. They had work done on the drains and that's it. They sold the house a few years ago, I gathered they just plastered over everything, out of sight of mind!

In the past when we had structural engineers out, they all mentioned that their house will now be the weak point of the 2 structures as they have had no underpinning or piling done, so if there is still movement that it will be theirs that moves. Unsure how true that is.

The nearest big tree is about 20 metres away so I don't think it's the trees caused it. I reckon it's just cos its built on quicksand!

I'll try and get a picture up to show the bulge. There is slight bulging on the rear wall that you can hardly notice (might be imagining it!) but it's very noticeable on the gable.
Richard77
Posts: 62
Joined: Thu Sep 19, 2024 3:26 pm

Re: Possibly a bonkers idea - cavity wall insulation

#65

Post by Richard77 »

Sorry about the mess in them!

Image
2015... Water approx 6ft down

Image
2015.. bulge

Image
Area that bulges is from 1st floor.. to around the area near side gate. So approximately the bottom left quarter of the gable.

Image
2024.. side view bulge
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