ᐅ New Insulation Between and Under Rafters: Effective Measures Against Summer Heat?
Created on: 13 Jul 2016 17:25
G
GHovxHello experts,
When building a house, you read a lot, learn a lot, and keep coming up with new questions. I hope you can help me.
We are renovating an older building, and this concerns roof insulation. We are aiming for a combination of insulation between and below the rafters, which we want to install ourselves.
Current new roofing structure installed by the roofer (from the outside inward):
1) Clay tiles
2) Counter battens and battens
3) Underlay membrane: Dörken Delta Vent S
4) Old round rafters, 12 cm (5 inches) thick (still in good condition!)
- Clear spacing between rafters 55–56 cm (22–22 inches)
For insulation, we are targeting KfW standard (24 cm (9.5 inches) thickness with a thermal conductivity of 0.035 W/mK or equivalent), since this minimum requirement qualifies us for municipal funding.
After reviewing my current plan with the local specialist dealer, we want to proceed with the following setup soon:
5) Between the rafters: 12 cm (5 inches) mineral wool insulation (thermal conductivity 0.035 W/mK) [Knauf Insulation]
6) Perpendicular to the rafters on the inside, an additional layer: 12 cm (5 inches) mineral wool
- Crosswise to the rafters, 6 x 12 cm (5 x 5 inches) glued laminated timber beams (“glulam”) will be used as a clamp for the below-rafter insulation
7) Vapor barrier: exact type still unknown; the dealer wants to consult with Knauf as this kind of “thick” below-rafter insulation is unfamiliar to him
8) 3 cm (1 inch) battens as substructure for drywall
9) 12.5 cm (5 inches) gypsum board
My question so far: Are there any objections or potential problems anyone sees?
We want to use the attic as a bedroom and want to do everything necessary early so it doesn’t feel “stuffy.” I read today that using materials with high thermal mass on the interior side can help with this.
My question: We are looking for a good balance between "enough remaining interior space" // "adequate insulation" // "reasonable cost-benefit ratio."
Would it be possible to fill the 3 cm (1 inch) space provided by the battens under point 8) with wood fiber boards? How would you install these—can they be cut to size, laid on the cross battens, and then drywall screwed in front?
Would these 3 cm (1 inch) be noticeable at all later on, or would they just be a waste of money?
For your information: Three large roof windows with external roller shutters are also installed.
Thank you for your opinions,
Gerrit
When building a house, you read a lot, learn a lot, and keep coming up with new questions. I hope you can help me.
We are renovating an older building, and this concerns roof insulation. We are aiming for a combination of insulation between and below the rafters, which we want to install ourselves.
Current new roofing structure installed by the roofer (from the outside inward):
1) Clay tiles
2) Counter battens and battens
3) Underlay membrane: Dörken Delta Vent S
4) Old round rafters, 12 cm (5 inches) thick (still in good condition!)
- Clear spacing between rafters 55–56 cm (22–22 inches)
For insulation, we are targeting KfW standard (24 cm (9.5 inches) thickness with a thermal conductivity of 0.035 W/mK or equivalent), since this minimum requirement qualifies us for municipal funding.
After reviewing my current plan with the local specialist dealer, we want to proceed with the following setup soon:
5) Between the rafters: 12 cm (5 inches) mineral wool insulation (thermal conductivity 0.035 W/mK) [Knauf Insulation]
6) Perpendicular to the rafters on the inside, an additional layer: 12 cm (5 inches) mineral wool
- Crosswise to the rafters, 6 x 12 cm (5 x 5 inches) glued laminated timber beams (“glulam”) will be used as a clamp for the below-rafter insulation
7) Vapor barrier: exact type still unknown; the dealer wants to consult with Knauf as this kind of “thick” below-rafter insulation is unfamiliar to him
8) 3 cm (1 inch) battens as substructure for drywall
9) 12.5 cm (5 inches) gypsum board
My question so far: Are there any objections or potential problems anyone sees?
We want to use the attic as a bedroom and want to do everything necessary early so it doesn’t feel “stuffy.” I read today that using materials with high thermal mass on the interior side can help with this.
My question: We are looking for a good balance between "enough remaining interior space" // "adequate insulation" // "reasonable cost-benefit ratio."
Would it be possible to fill the 3 cm (1 inch) space provided by the battens under point 8) with wood fiber boards? How would you install these—can they be cut to size, laid on the cross battens, and then drywall screwed in front?
Would these 3 cm (1 inch) be noticeable at all later on, or would they just be a waste of money?
For your information: Three large roof windows with external roller shutters are also installed.
Thank you for your opinions,
Gerrit
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