Single storey extension advice - foundations

Joined
4 Feb 2011
Messages
22
Reaction score
0
Location
Surrey
Country
United Kingdom
Hi there
I live in an end terrace and looking to build a small single storey side extension. My house and garden are all built on concrete - the soil in the garden is only about 3 inches thick and sits on concrete (my street sits on what used to be a big factory site). Is it still necessary to dig deep foundations or can a slab be poured on top of the existing concrete and then build a wall on top? How does having existing concrete rather than soil complicate things?
Thanks
 
Sponsored Links
How does having existing concrete rather than soil complicate things?
What if a drain company wished to dig along side your wall, thus removing your concrete? You would be mad to rely upon 'supposed' existing concrete foundations without verification. Yours will need to be independent of any other structure.
 
Surely 3" of soil on concrete will be 3" of mush for six months and 3" of crust for the other? And no plants.

Is this 'built on concrete' theory correct?
 
Sponsored Links
Have a look for any any extensions in the street, note the addresses of one's that look recent. Phone the council building control team and ask to speak to the officer for your area. Ask him if he knows what the foundation situation will likely be, and if not give him a few addresses and ask if he could have a quick look at any plans.
 
Have a look for any any extensions in the street, note the addresses of one's that look recent. Phone the council building control team and ask to speak to the officer for your area. Ask him if he knows what the foundation situation will likely be, and if not give him a few addresses and ask if he could have a quick look at any plans.

Thanks, I'll do that. There are some council owned garages a few metres away and you can see that a slab has been laid on top of the existing concrete and then the brick wall built on top of that. My extension wouldnt be much taller in height than these.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top