Advice please, lower front wall cement and failing

[TheSpid]

Hi there all, back for some of the fabulous advice,

To the side of the house we have an attached annex, what was once an old byre - obviously renovated in the time of cement and concrete worship. I was cutting back the bushes there [don't ask, I didn't plant them] and discovered the cement render cracked and bits falling out. So had a bit of a wiggle at it and large chunks very easily fell off. What is behind though isn't exactly what I was expecting - soil, clay, worms, a red ants nest, lots of roots from said bushes [on hubbies urgent list to remove] - we are on a slight hill and the house sits uphill to downhill - there are stones as a foundation, but they are shallow compared to the depth of the cement. pic with the screwdriver shows where I think the stone foundations stop [I've not explored too far as the light was failing]. So the question is what do I do? Take all the cement off, inside and out [though I think the level of the floor inside is higher than the top of the cement outside] ad then what? Lime render over soil? Help? Please?

 

[Kearn]

Immediate guess would be that the ground level outside has been lowered, presumably when 'rennovated' in the 60s or so(?) and the concrete is an attempt to make good what was exposed. If indeed those stones are the extent of the foundations, then that's not what they are any more :shock:

Has much more load has been added to the original structure when it was changed? Those stones really don't need the opportunity to shift laterally...

In answer to you Q, lime is unlikely to do much if anything here, bar the aesthetic. It's strength lies in direct compression in the vertical plane, so great for a pile of bricks sitting directly above one another, loading downwards. It could be here that someone was attempting to provide lateral rigidity to support the foundation stones that are no longer underground buried in earth in all sides.

I would dig carefully in any further investigations...

 

[TheSpid]

Hmm dodgy then, don't think it has been dug out but I know people that have lived here all their lives so will ask if they can remember. It was a byre and is now a flat - so I expect a bit more loading. Will it need underpinning then if the stones really do stop at the screwdriver level? Or a retaining wall built? I guess a structural engineer is needed?

 

[george2019]

I think remove the organic material in one area and see what is holding the house up. Followed by a structural engineer visit.

If it is well below the internal floor level, and there is something solid behind the 'soil', then I think some sort of cast concrete or masonry plinth (backfilled) up to the start of the render.

 

[TheForge]

A plinth, unless very substantial, will have no effect on resisting lateral movement.

Having said that is there any evidence of movement? It’s obviously been like it for a while and may be in happy equilibrium.

Dig a narrow exploratory ‘trench’ to confirm this really is the extent of the wall then speak to a structural engineer if the wall really is floating.

 

[TheSpid]

No evidence of movement at all, very much seems in happy equilibrium - the cement/concrete fell off the wall with utter ease, like sand falling - it's been like this for nearly fifty years if not longer, I'm sure at the beginning the cement was stronger but looks like it has been failing for quite some time.

Thank you all.

 

[george2019]

A plinth, unless very substantial, will have no effect on resisting lateral movement.

Having said that is there any evidence of movement? It’s obviously been like it for a while and may be in happy equilibrium.

Dig a narrow exploratory ‘trench’ to confirm this really is the extent of the wall then speak to a structural engineer if the wall really is floating.

My thinking wasn't so much holding back the sub-base as consolidating and protecting it from further weathering.

It might be that the sections of degrading/organic material is being arched over by the wall above... but if the whole section gets eroded then it will, eventually, move.

 

[TheSpid]

So - further investigations revealed stone all the way down the ground in a good few places and presumably further into it too, and so by extrapolation [without deconstructing the whole thing] the foundations are fully intact. There was too much soil in the way on the first day and the light was failing fast that I didn't test in enough places etc and was panicking. According to the local farmer [lived here for 80 years] the ground level has never been lowered and the road running by the house is the same height as the ground level and has been there for a very, very long time so we are fairly certain there has been no lowering of the ground level which mean this building has sat here for centuries without movement. The cement seems to have been put on to conceal the very rugged and undulating stone foundations, the farmer was trying to remember when it was rendered. I expect they thought the cement was 'prettier'. Plans are afoot.

 

[88v8]

Old houses do throw up some surprises.

The cement render was serving the useful purpose of preventing the soil under the keystones from being washed out.
You could replace it with more cement, or lime. But I would replace it.
A more robust wall agin the non-foundations would require..,.. a foundation... which might mean undermining the foundations.
So, I'd just put a decent render over it and leave well alone.
Yes, it will crack again eventually; regard it as a wear part like the spark plugs in your car. Not everything can be built on a 'last forever' basis.

Ivor

 

[TheSpid]

Old houses do throw up some surprises.

The cement render was serving the useful purpose of preventing the soil under the keystones from being washed out.
You could replace it with more cement, or lime. But I would replace it.
A more robust wall agin the non-foundations would require..,.. a foundation... which might mean undermining the foundations.
So, I'd just put a decent render over it and leave well alone.
Yes, it will crack again eventually; regard it as a wear part like the spark plugs in your car. Not everything can be built on a 'last forever' basis.

Ivor

Basically what we have decided Ivor - it needs something - not happy putting cement back over it [there are slight damp issue inside] so will use lime - will eventually take all the cement render off and lime render the whole thing.

 

[88v8]

...eventually ...

I'd keep the rain off it meanwhile.

Ivor