DIY Doctor UK DIY Forums

Started building an insulated stud wall room in my garage that I could keep from getting damp.

The garage is really a 2 bay timber shed that has been extended out to a third bay.

There is a brick foundation around the perimeter of the old shed and this also has been extended out to the third bay.
What was the wall between the old shed and the third bay is now a couple of wood pillars (aka fence posts).
The rectangular boxes represent the brick wall of the foundation under the ground.
The floor is concrete slab / screed



It occurred to me that I could support the roof of the old shed on one of the room walls. Like this.



Giving me more space above as I could get rid of the trusses and replace with rafters
My concern is what would be under the stud wall. Curently just a conrete slab / screed
Any suggestions for something easy-ish to install into / under a concrete slab (and who knows what underneath) that would support the base of the stud wall properly even if I was to load the smaller section of the roof with something like PV panels?
Suggestions much appreciated

Hi smalldave,
Your structural design will be dictated by the roof covering, if it is plain tiles you will probably need purloin half way along the long span. If it is felt tiles you may get away with your proposal provided the rafters are large enough.
Regards S

Thanks for that. Will be a felt roof so hope rafters will do as long as I size them right. My real worry is changing the loading from the bricks on the perimeter of the foundation to at least partially loaded on the slab through the new central wall.
Am I just overthinking it?

Hi smalldave,
If the garage floor is a concrete slab 125mm thick or more you should be fine with such a lightweight roof. Check the depth of concrete by drilling with a long masonry drill two or three places along the line of the new stud wall.
Regards S