Hey folks,
So, I’m building a 7m x 4m double skin (brick and block) workshop at the back of garden - no building regs/planning required.
1). I’m planning the oversite ‘sandwich’ but can’t see the need to screed. Why can’t the top 100mm concrete layer become the finished floor which I plan on tampering and levelling against the perimeter blockwork? It’ll be a rough finish but fine for a workshop surely and I can lay rubber interlocking tiles afterwards. What am I missing?
2). As its a light duty workshop, my proposed sandwich was as follows:
50mm hardcore type1
25mm sand blinding
Plastic membrane
70mm celotex (or polystyrene perhaps?)
Polythene
100mm concrete
Will the above be ok?
3). Do I need 25mm celotex around the perimeter as i’m concerned about the concrete cracking? Is the perimeter insulation intended to insulate or act as an expansion gap?
4). Why must the oversite insulation be PIR - why can’t it be the cheaper polystyrene / jablite? Is that just down to U values? This will be a back-of -garden workshop afterall
5). Does the cavity between walls need to be 100mm? Can it be 50mm?
So, I’m building a 7m x 4m double skin (brick and block) workshop at the back of garden - no building regs/planning required.
1). I’m planning the oversite ‘sandwich’ but can’t see the need to screed. Why can’t the top 100mm concrete layer become the finished floor which I plan on tampering and levelling against the perimeter blockwork? It’ll be a rough finish but fine for a workshop surely and I can lay rubber interlocking tiles afterwards. What am I missing?
2). As its a light duty workshop, my proposed sandwich was as follows:
50mm hardcore type1
25mm sand blinding
Plastic membrane
70mm celotex (or polystyrene perhaps?)
Polythene
100mm concrete
Will the above be ok?
3). Do I need 25mm celotex around the perimeter as i’m concerned about the concrete cracking? Is the perimeter insulation intended to insulate or act as an expansion gap?
4). Why must the oversite insulation be PIR - why can’t it be the cheaper polystyrene / jablite? Is that just down to U values? This will be a back-of -garden workshop afterall
5). Does the cavity between walls need to be 100mm? Can it be 50mm?