How deep are you foundations ?

[Jakido]

Hello

Has anyone built a single storey extension locally recently? If so, could I ask how deep your foundations needed to be?

Thanks in advance

[Northern Star]

Hi

In certain parts we had to go down to 1.8 meters. Only 1 meter was included in the original price.

[Jakido]

Thank you

[bargee99]

I've just had an extension built in Worcestershire where I moved to from East Dulwich. My building quote was also for 1 metre. When they dug out the hole for the foundations they found that the house foundations went down 1.8 metres. Building control insisted that the builders match the depth of the house foundations. The builder said that the fear is that the extension "pushes" on the house foundations if the depths don't match. You therefore won't know until the foundations are dug. Best of luck.

[ED Light]

Generally 1.2m for a side extension, but we had to go down to

1.6m as there was concern the tree next door would drink too much water from the ground and affect shallower foundations

[Lemming]

bargee99 Wrote:

-------------------------------------------------------

Building control

> insisted that the builders match the depth of the

> house foundations.

The majority of the Victorian houses around here don't have foundations in any modern sense. Our (1 storey) extension was required to have 2.4m foundation trenches dug but the rest of the (3 storey) house sits on fewer than half a dozen stepped-out bricks!

[KidKruger]

Yeah same here - 3-storey Victorian house, not much foundation to speak of.

[diable rouge]

Every situation is unique, I've known houses in the same street have totally different foundation designs for near identical extensions, so one should always employ a structural engineer to design the foundations and structural framework to suit the local conditions, rather than rely on what other people have done. A SE will carry out preliminary checks/tests on the soil conditions, for instance a common problem in London is tree roots causing the clay soil to 'dessicate', thus making it unsuitable for standard deep foundations, and instead requiring a series of very deep pile foundations. A SE will also allow for differential movement between the old and new, as should any decent builder e.g. movement joints...

[Lemming]

Yes as DB says, there are all sorts of rules and regs unique to specific situations (depth of foundation, proximity and type of tree, soil type & water content, requirement for compressible clay boards). In any case you can't just do what you like (or what other people have done) because the building regs guy won't sign if off unless he's satisfied it complies with the regs.

Furthermore, it would be great if structural engineers and buildings regs people are unanimous in their agreement as to the interpretation of those regs, but IME they are not always so.

[Orange owl]

Hi. Just building extension in peckham ,had a soil test done at www.k4soils.com and this reduced the footings by 40cm

Good luck

[niall]

was this the B side?