extension on top of garage HEEEEEEEEEEEELP

[swes]

Hi i have a semi detached house with garage built on to the side and was wondering if i will need to underpin the foundations for a timber framed extension on top of it...Any ideas.My friend across the road had to underpin but is completely detached on the garage side were mine is attached to another garage.its single block ......Also i have a pit in my garage so will i have to fill it in for strength...

 

[mikric]

Only way to find out is to dig down and expose the foundations so see what foundations you have got.

 

[DevilDamo]

As mentioned, the only way to find out would be to expose the existing foundations.

You may find that going in to planning for a first floor extension over an existing garage is only favoured by the council if the wall at first floor is set back from the wall at ground floor, which would result in a beam(s) being provided within the new first floor to support the new first floor wall, which would sit on the existing walls.

Any lintels over door/window openings would also have to be suitable to take any additional loading.

 

[swes]

Was told last night that it would work out better to just demolish the garage then dig for the foundations , any one got any comments on this he is a very good friend of mine. and a time served builder..the under pinning will take longer as i will have to hand dig it by the meter and try to get reinforcment bars in with the garage up

 

[DevilDamo]

In some cases, it can work out more cost effective to go down the re-build route. However, I'm pretty sure there are some PD differences if you're converting/extending an existing garage, as opposed to demolishing and re-building. You'd have to double check that with your local planning authority.

 

[noseall]

If you have the opportunity to demolish rather than underpin, go for demolishion. Underpinning is invasive and can have a negative effect before any positives are forthcoming.

Bite the bullet and have shiny new solid footings.