What's the crack, subsidence?

heavymental

My mum's house is an old mid terraced house in Wiltshire. Built in the 1800s it has been fine for many years but over the last few years has started developing a few cracks here and there. It's been a minor concern but we haven't been too worried as it's been standing over 125 years. Recently one of the interior doors has become impossible to close and a few more cracks have been noticeable but only inside the house at the moment. Our concern is obviously around what the cause is, whether it'll get worse and what to do about it. One suspect is the large pyracantha shrub that covers the front of the house - could it be soaking up too much moisture from the soil? The soil itself is free draining.

The question is who would I be looking to speak to? A structural engineer? A builder? Some kind of specialist? Also, has anyone got any experience in the matter!?

Below is a picture which might be of some use to give you an idea. It's the area above the door frame that no longer fits the door.

photonic69

There's been a lot of settlement this year due to the unusual lack of rain and high temps. Our neighbour up the road is an end of terrace and next to an avenue of trees. His house has developed quite a few cracks as the trees have sucked the moisture out of the ground. He's a civil engineer but isn't too concerned at the moment. However if you are then get in touch with a surveyor to investigate.

heavymental

Cheers yes my old man was a civil engineer too but not around anymore to tell my ma (and me) not to worry about it. I think the problem maybe got a bit worse when he dug out the lawn in the front garden and replaced it with gravel. Makes me think moisture is the main problem.

rakkor

Our South London house is built on clay and bounces around like nobodies business, needless to say we have cracks appearing all the time which really worries my missus. So much sh we have had it surveyed twice in the last 12 years just to put her mind at rest. The result both times is "normal movement for this area" If you're worried have a survey done.

heavymental

Ok thanks. Not sure what can be done about it anyway 🤷 Presumably any works to stabilise it would be pretty major operations.

photonic69

You could get a crack gauge thing to monitor it. Pretty cheap

https://smithsurveyingequipment.co.uk/shop/surveying-accessories/monitoring/datum-tell-tale-wall-crack-monitor-gauge/

This will tell you if it's getting any worse.

PMark

I have just dealt with an issue like this, we initially thought we would need to pay £20k to reinforce/stabilise the walls of the house. Turns out it was just the drain which goes down the side of the house which needed sorting out (around £3k).

We got a structural engineer to take a look and they drilled some holes around the house and stuck cameras down to see what was happening. They then arranged for a drainage company to sort the drains.

Pross

Are the cracks visible outside as well and are they 3mm or more? Also, have the windows become harder to open and close?

As others have said, the drought this summer has caused a lot of shrinkage in soils. I’ve had a new scheme where 100m plus of newly laid, high spec footway had to be replaced as it cracked down the middle.

Worth a look at this https://hoa.org.uk/advice/guides-for-homeowners/for-owners/subsidence/

davidof

Clay soils (as said above) and drought.

It is even worse in Northern France where they don't seem to bother with foundations and loads of houses are falling down.

heavymental

The cracks aren't visible from the outside and not quite able to accommodate a 10p piece in the crack. The house doesn't have much in the way of foundations either because it is so old. I think we'll get a structural engineer to have a look but maybe we'll wait until spring and see if the winter has an effect. I think the massive shrub will be having an effect and looking at that link Pross posted I guess it's not ideal being right up against the front of the house (!) although the cracks seems much more generally spread around the house rather than at the front. I don't think it'll be much to worry about but it would be useful to have the reassurance of someone who knows the characteristics of the area and building practices. I guess it's a fairly unexpected side effect of climate change that the ground is potentially going to be dryer than normal for long periods and could cause problems with buildings.