Are there any underpinning experts on SD?

[Trickyd66]

I am no expert as sparks by trade, but if you saw the cracks (internal and external) on our 1940's house it makes yours look good. If in doubt, get a structural surveyor to look at it and advise.

 

[Emilio]

Looks like your addition is primarily comining loose at the top, which would indicate that the end that is fartest away from the house is sinking. Dig to or drill into something solifd there and pour additional foundations there and it should be fine.

 

[eldon]

As Old 30-06 says. It’s called ‘hit and miss’ mass poured underpinning.

You need to dig down until you find a suitable load bearing strata.

And aren't you supposed to stick a vibrator into the sticky mess for increased (job) satisfaction

 

[nf-fuse]

Respectfully, I disagree with you on this and the broad generalisation.

I work in the construction industry as a surveyor. You would be astounded by some of the issues we see in modern properties.

I’m not saying we don’t see issues with older properties. But to say modern properties are constructed better is simply not the case.

What I meant in my earlier comment was; because one house built in 1900 (ish) has an issue, that doesn’t mean another will or is more likely to have the same issues.

Sorry, this isn’t intended to be an argumentative comment, and I apologise in advance if that’s how it appears.

I've been a builder since 2006.....

Perhaps I should not have used the term 'better'. What I'm getting at is that in theory modern housing should, emphasis on should, be built with footings that obviate most issues that you see with basic subsidence. I recently built a property with footings down to 2.5m on one corner due to not especially close trees.

I've seen houses for yesteryear where if you pull up the floor boards you find earth and it's built on top of that. Believe me I've seen it all, as I'm sure have you. I agree a lot of modern housing isn't great but you need to guard against survivor bias. A lot of the housing stock in this country is absolute dross from times gone by.

My point about the age of the property is merely related to my opinion that those age properties *can* be more prone issue like clay heave due to shallower footings etc. I'm my experience any way. Of course be properties haven't had long enough to sink in to the ground yet.....

 

[nf-fuse]

Saw it first last summer, my builder advised waiting and watch the cracks grow. It grew as expected so now am on the fix it mode. Me being 75 digging is not for me so paid help will be used.
Here are a few pics of the damage. No trees shrubs or plants are nearby. The bedroom shows movement away from main house as does the bathroom add on, the last on left but the lower kitchen to main house structure shows no cracks yet!

Well I've seen a lot worse I'll say that much

Could be anything to be honest. I've seen houses undermined by a leaking water pipe.

 

[bobt]

I've been a builder since 2006.....

Perhaps I should not have used the term 'better'. What I'm getting at is that in theory modern housing should, emphasis on should, be built with footings that obviate most issues that you see with basic subsidence. I recently built a property with footings down to 2.5m on one corner due to not especially close trees.

I've seen houses for yesteryear where if you pull up the floor boards you find earth and it's built on top of that. Believe me I've seen it all, as I'm sure have you. I agree a lot of modern housing isn't great but you need to guard against survivor bias. A lot of the housing stock in this country is absolute dross from times gone by.

My point about the age of the property is merely related to my opinion that those age properties *can* be more prone issue like clay heave due to shallower footings etc. I'm my experience any way. Of course be properties haven't had long enough to sink in to the ground yet.....

a couple of years ago I saw an extension the same,no oversite conc, did a foundation trial hole, found top of concrete 50mm below ground,(great trench fill) er the bottom of the concrete was 75mm down, yes a major windows firm had built it, supposed to be a conservatory, but tiled roof, cavity walls and only 3 windows, on ONE INCH of concrete,
was a BCO for 50 years, now retired, the standard of monkey on site has gone down every year, no one wants to get their hands dirty, only 10% or less are actually competent,

 

[eggy74]

why would an architect be ever be specifying foundations? that is the SE's remit. and you saw this several times.......

Generally builders build from a set of plans provided by the architect, the regs. will be printed on these plans as per what the ground conditions and wall/roof type require, there are tables the architect uses to "calculate" the loads. Some smaller jobs are done without architect or structural eng. and the regs are agreed with the bco, but i think this way is dying as the bco's these days have less practical knowledge and are not willing to make decisions

 

[bobt]

thanks to grenfell and dame hacket for the last year BCOs are told NOT to make design/instructions, no longer can a builder ask his local BCO to suggest a solution,
most BCOs see 3-4 excavations a day, with all the problems, and usually know a way to solve problems,
a builder may see one exc a month,

 

[Bavarianbrit]

My problem is as it is a bolt hole in the UK and gets used by us for say 2 months per year so I am not able to keep an eye on it. Thanks for all the advice folks.

 

[Norfolk Horn]

My problem is as it is a bolt hole in the UK and gets used by us for say 2 months per year so I am not able to keep an eye on it. Thanks for all the advice folks.

My advice is if you have building insurance and you are willing to pay the excess of say a thousand pounds do nothing and get the insurance company involved. Do nothing before they visit so they can't blame you.
My guess will be a problem from the drain from that downpipe. Cracked or roots or the like allowing water to escape and washing out fines from the area of the footing.
Don't add additional weight by under pinning until a soil survey is carried out can this can make matters worst.
If you want to have a quick look at the drains before contacting the insurers, get a company in and get a copy of there video and report to go forward.
Some times in these cases it is necessary to form a movment joint between the original build and the extension as the extension.
If the drains are the problem they can be lined or replaced.
This is quite a common issue.
Hope this helps.

 

[Utectok]

This is a controversial approach but I deal with a lot of property and I’ve lost count of the times I’ve been advised to spend 10s of thousands underpinning stuff. 99% of the time I’ve redecorated and kept an eye on it. Im not some kind of risk taker but it’s very common for buildings to move and settle and mostly they don’t move again for 30/50 years. If it doesn’t get any worse you can probably leave it would be my advice. Mark the gaps with pencil line to see if they shift. If they don’t redecorate and watch. I suspect the building will stand long after we are all dead.