Member
· Västra götaland
· 335 posts
We are at the starting point of possibly extending our house by 30 sqm with a slab foundation. The quote we have so far includes 200 mm insulation in the slab. I have a couple of questions that I hope someone can help me with before we get started. The plan is to have a construction company finish the roof completely and build the frame, and then I will take over and handle the rest.
Question 1: Is 45 + 145 + 45 sufficient for walls today? Are there U-values calculated for this construction? I have been informed that the wall should have a U-value of 0.18, the roof 0.13, and the floor 0.13. Is that wall enough, and how much insulation is needed in a slab foundation to achieve 0.13?
Question 2: How do you deal with the plastic that should be placed between the 145 and the inner 45 stud? Should it just stop at the concrete slab, or should it be attached in some way? Should any raised sill seal be used under the 145 when they raise the wall?
Question 3: Should there be plastic, or is it safety fabric that's required in the ceiling?
Question 4: Is it best to have them place edge elements against the existing slab we have today, or can you do like some others and just lay sill paper along the old slab? They mentioned this when I talked to them last time. (It's obviously cheaper for them.)
Question 1: Is 45 + 145 + 45 sufficient for walls today? Are there U-values calculated for this construction? I have been informed that the wall should have a U-value of 0.18, the roof 0.13, and the floor 0.13. Is that wall enough, and how much insulation is needed in a slab foundation to achieve 0.13?
Question 2: How do you deal with the plastic that should be placed between the 145 and the inner 45 stud? Should it just stop at the concrete slab, or should it be attached in some way? Should any raised sill seal be used under the 145 when they raise the wall?
Question 3: Should there be plastic, or is it safety fabric that's required in the ceiling?
Question 4: Is it best to have them place edge elements against the existing slab we have today, or can you do like some others and just lay sill paper along the old slab? They mentioned this when I talked to them last time. (It's obviously cheaper for them.)
Member
· Västra götaland
· 335 posts
No one has a clue?? I don't believe it!!
1)
Check out www.isover.se they have construction suggestions with calculated U-values.
2)
One way is to pull it down to the slab and then clamp the plastic between the seal and the internal 45's rule. That way, you get a tight fit.
3)
Safety weave... But I don't have much knowledge there...
-If you mean on the roof and not above the ceiling (under the rafters)...
4)
(No comments)
Check out www.isover.se they have construction suggestions with calculated U-values.
2)
One way is to pull it down to the slab and then clamp the plastic between the seal and the internal 45's rule. That way, you get a tight fit.
3)
Safety weave... But I don't have much knowledge there...
-If you mean on the roof and not above the ceiling (under the rafters)...
4)
(No comments)
Member
· Västra götaland
· 335 posts
Oki thanks for this.
The safety net was intended to be under the rafters. Do you mean that it is placed ON the roof??
The safety net was intended to be under the rafters. Do you mean that it is placed ON the roof??
Aaahaa... I think we're talking about slightly different things...
You can often place a foil of the safety fabric type on top of the rafters and exclude the usual sheathing, this fabric should then be the waterproofing layer in the outer roof. Be sure to buy a diffusion-open fabric, then you can eliminate all air gaps in the outer roof construction! - Simple and more moisture-resistant than the classic "cold attic"!!!
- However, ensure that you maintain the stability of the roof structure if you exclude the sheathing, this is something the truss designer can answer!
Underneath the rafters (interior ceiling), it should functionally be airtight and diffusion-proof (plastic), safety-wise I'm not sure if safety fabric is required?
- Anyone know?
You can often place a foil of the safety fabric type on top of the rafters and exclude the usual sheathing, this fabric should then be the waterproofing layer in the outer roof. Be sure to buy a diffusion-open fabric, then you can eliminate all air gaps in the outer roof construction! - Simple and more moisture-resistant than the classic "cold attic"!!!
- However, ensure that you maintain the stability of the roof structure if you exclude the sheathing, this is something the truss designer can answer!
Underneath the rafters (interior ceiling), it should functionally be airtight and diffusion-proof (plastic), safety-wise I'm not sure if safety fabric is required?
- Anyone know?
Click here to reply