building above a single storey extension

davidriley

Hi all, hope someone may be able to point me in the right direction.

Our house has a single storey rear extension with a pitched roof. It was built in about 1992.

How do you know whether it is feasible to build above this extension - to enlarge an upstairs bedroom??

Many thanks for looking!

Moneymaker

Check the depth and type of foundations first. Ask your local Planning Office. They are usually quite helpful.

davidriley

Thanks for the reply. How do you check the depth & type of foundation?

Thanks again

flang

the only way to check the foundation depth is to dig a trial hole next to the foundation.
It was common in the old days to only put enough foundation in for the building only (cheaper) however nowdays if your building a single story extention you are required to put a deeper foundation incase you want to build on top in the future.

uncle_buck_3

As your present extension is quite recent I would imagine that your local planning office (Council) would have details of it on file….for planning permission purposes etc….the plans will show the foundation details.
I think you should also have a copy of the plans for your extension with the deeds of your property.

Avoriaz

Even if you can find the plans I suggest that you dig a hole anyway and have a good look. The plans tell you what the architect and/or builders told the council they were building. It does not necessarily mean that is what they actually built. There is a small risk that they were cowboys who skimped on the foundations. The small cost, effort and inconvenience of digging a hole could save you a £50,000 mistake.

You also need to check that the walls are a double course of bricks or brick and block and not a single course. For a 1992 extension it is highly unlikely that they are single course and it is easy to check. Just open a window or door and measure the thickness of the walls. They should be about 11 inches or so.