Testing existing foundations

[vincentianpinner]

Anyone know if there's a way of testing the quality of existing foundations. To check if it's strong enough to build a new structure on.

 

[Scally-Ho]

Do you know the depth of the existing foundations and how the ground is made up?

 

[noseall]

Anyone know if there's a way of testing the quality of existing foundations. To check if it's strong enough to build a new structure on.

Not without knowing the concrete thickness, depth (in the ground) and the ground conditions - no.

 

[vincentianpinner]

It's supposedly deep enough etc. but is there a way of testing strength.

 

[Scally-Ho]

I forgot to ask how old the existing property is. Some early footings were very shallow and bricked up from a bed of ballast, so age is important.

 

[freddiemercurystwin]

Assuming this is a domestic setting then ordinarily you dig a test pit, dig down until you find the foundation, the hole needs to extend far enough to determine how much wider than the wall it is, then dig down a bit more to find the depth, invite your Building Control officer to peer down the hole and say yay or nay.

I've never known a BCO ask for a concrete test for a domestic job but the strength can be tested, you would send a core sample away to some lab somewhere and they would test it. Might have to have a few cores tested.

 

[drpepe]

I reused foundations for a new extension. Council BC asked for a couple holes to determine depth and width.

 

[vincentianpinner]

I forgot to ask how old the existing property is. Some early footings were very shallow and bricked up from a bed of ballast, so age is important.

I dug down in one area so far. It's at least a metre of concrete.

Assuming this is a domestic setting then ordinarily you dig a test pit, dig down until you find the foundation, the hole needs to extend far enough to determine how much wider than the wall it is, then dig down a bit more to find the depth, invite your Building Control officer to peer down the hole and say yay or nay.

I've never known a BCO ask for a concrete test for a domestic job but the strength can be tested, you would send a core sample away to some lab somewhere and they would test it. Might have to have a few cores tested.

I'll try and find a company that does it. Might be worth it for peace of mind.

 

[^woody^]

You would normally test the ground soil for bearing capacity not the foundations.

Any foundations would be checked visually for dimension and form, and if need be whacked with a hammer.

 

[aveatry]

Same here I dug down to find the depth of existing, had to dig 2 pits one at the front and one at the back /side. Got my tape measure out and everything for the BCO who just looked down the hole and said yep that's OK

 

[vincentianpinner]

You would normally test the ground soil for bearing capacity not the foundations.

Any foundations would be checked visually for dimension and form, and if need be whacked with a hammer.

So if it looks right it is right. Plus a bit of a whack. That would save a lot of messing about.

 

[^woody^]

Yes. Generally, the foundations for a single or double storey are OK for a third storey