Hi,
Now I have the drains all in on my ground floor extension it's time to put the oversite down.
To get the required 150mm min of space between the top of the oversite and the bottom of the joists the oversite would have to be about 75mm lower than the outside ground level.
The BCO told me that if I put a damp proof membrane in below the oversite that I can have less than the 150mm space so I think this is what I'm going to do, it means that the sleeper wall will only be 1 brick in height with a 2" x 4" wall plate, then the 6"x 2" joists.
Do the joists & wall plate need to be pressure treated timber?
If I can squeeze it in would it be ok to use a concrete block on it's side (100mm) as the sleeper wall?
I've read that the wall plate isn't fastened to the sleeper wall it just sits on a bed of mortar, if this is the case how doesn't it twist all over the place when it gets damp from the mortar? ....I was intending to fasten it down to the blocks to stop it twisting.
Any thoughts?
Cheers.
Now I have the drains all in on my ground floor extension it's time to put the oversite down.
To get the required 150mm min of space between the top of the oversite and the bottom of the joists the oversite would have to be about 75mm lower than the outside ground level.
The BCO told me that if I put a damp proof membrane in below the oversite that I can have less than the 150mm space so I think this is what I'm going to do, it means that the sleeper wall will only be 1 brick in height with a 2" x 4" wall plate, then the 6"x 2" joists.
Do the joists & wall plate need to be pressure treated timber?
If I can squeeze it in would it be ok to use a concrete block on it's side (100mm) as the sleeper wall?
I've read that the wall plate isn't fastened to the sleeper wall it just sits on a bed of mortar, if this is the case how doesn't it twist all over the place when it gets damp from the mortar? ....I was intending to fasten it down to the blocks to stop it twisting.
Any thoughts?
Cheers.