Foundations not deep enough on already built extension

ch1981

Not sure if Im in the correct forum.
So my parents built an extension (2 storey), on their bungalow about 6 years ago.
They have had smell of damp in one of the rooms and it transpires through my dad investigating that the foundations are only about a foot deep! Builders that did the work are no longer around.
He seems to think he can fix himself, build trenches fill with concrete etc.
Is this possible?
Could it need to be completely knocked down?
Funds are a problem, I personally don't think diy route is best way to go though.
Any advice?
Thanks

BryanF

Get a structural engineer. I would caution against DIY remedial works of this nature. If your dad is such an expert how did he not spot this 6 years ago during construction ?

Btw we cannot offer structural advise here as its against the forum charter.

ch1981

Pretty sure I didn't say he was an expert, he was actually ill at the time of construction.

BryanF

ch1981 wrote: »

He seems to think he can fix himself

Expert?

Gumbo

ch1981 wrote: »

Not sure if Im in the correct forum.
So my parents built an extension (2 storey), on their bungalow about 6 years ago.
They have had smell of damp in one of the rooms and it transpires through my dad investigating that the foundations are only about a foot deep! Builders that did the work are no longer around.
He seems to think he can fix himself, build trenches fill with concrete etc.
Is this possible?
Could it need to be completely knocked down?
Funds are a problem, I personally don't think diy route is best way to go though.
Any advice?
Thanks

Get engineer engaged and builder/your father ready. Expose existing foundations and have the engineer on site to guide you throughout and to determine exactly what's there now and what needs to go there.

Engineer will issue a plan of action and you get the contractor/father to follow these "instructions".

There is no other way, there is no one guide fits all and every house and ground conditions can be different so get a plan that suits your house and site conditions.

Calahonda52

before u do anything join the Hansel and Gretel breadcrumbs in your post for me that show damp = foundations too shallow.

I just don't see it

One shot on kill

I can under stand how a shallow foundation causes damp. There is another u Dee lying problem here I would think.

Hasn't said that if the foundation was skimped on they most proberly skimmed on other stuff to.
How did you come to the problem being the foundation anyway.

Mplant

ch1981 wrote: »

Not sure if Im in the correct forum.
So my parents built an extension (2 storey), on their bungalow about 6 years ago.
They have had smell of damp in one of the rooms and it transpires through my dad investigating that the foundations are only about a foot deep! Builders that did the work are no longer around.
He seems to think he can fix himself, build trenches fill with concrete etc.
Is this possible?
Could it need to be completely knocked down?
Funds are a problem, I personally don't think diy route is best way to go though.
Any advice?
Thanks

Foundations are concrete on which the rising walls are built to floor level.the concrete is a foot deep as standard. So many variable things that could be causing damp,no radon barrier,no damp course,stepped foundations onto old build.filling trenches with concrete?is he trying to underpin?an engineer is your only way forward

RORY O CONNOR

Could be no DPC between the walls and the floor could be no no floor insulation or DPC below the floor slab. Don't see this as a foundation issue. You may have to take up the floor slab and dig out the ground below, adding in DPC/radon barrier and floor insulation and then tank up the walls. The floor slab may come up easily enough-simply get a drill and drill a hole until it penetrates through then measure the thickness of the floor slab. If its less than 150mm it will break out easily enough except if there is a mesh in it.

mickdw

Do you mean the foundation is just a foot below ground level or that the thickness of the foundation is a foot?
To be honest you can tell little from any of this.
A raft foundation could appear just below footpath level and the outer toe may only be 9 or 10 inches deep yet be 100 percent correct.
Are there any major cracks in the extension?

BryanF

Thread locked. No matter what the expertise of the posters, no one should give on line structural advice