jonnykerry
Registered User
- Messages
- 39
Hi all,
After a long few months we are at the stage where we will be putting the roof on our house soon. The problem is I've hit an in-pass in regard to what insulation build up to use!!
The basics are as follow's:
Rafter's will be 175 mm with a room in roof occupying 60 m sq live-able and 35 m sq of attic.
Rest of build Block with 250 mm cavity, passive slab on 300 mm of eps.
The options open to me:
1) Roof with 50 mm air gap, 130 mm metac in rafters with a suspended counter batten underneath to accommodate 200-250 mm more insulation, than air tight membrane. (This is the engineers favored option) traditional and with air gap peace of mind with regard to rot?
2) A passive roof system from Kore with 200 mm eps sitting on a osb base over the rafter and 150 mm eps between rafters.u value of 0.10. Concern about having a non breathable insulation over and between the rafters, or is this just over reacting??
3) Roof with counter batten over the rafters/ membrane, same suspended counter batten underneath and full filled with cellulose 340 mm 60 kg giving u value of 0.11. I have spoke to a few people including my architect who thinks this is the way to go as it is breathable and will have a good decrement delay due to weight. A installer has stated that if we counter batten above the rafter and use breathable membrane we can full fill between the rafter, Is this advisable?
Finally any suggestions on sealing the wall plate junction. Been presented 2 options by engineer:
1) Isover roll seal that goes under the wall plate and is compressed to seal
2) Wrapping a membrane around the wall plate lower end sealed into inner block wall plaster and top end taped into roof inner airtight membrane.
Sorry for the length of the post but really don't know which way to turn as all options given to me "seem" to be good.
After a long few months we are at the stage where we will be putting the roof on our house soon. The problem is I've hit an in-pass in regard to what insulation build up to use!!
The basics are as follow's:
Rafter's will be 175 mm with a room in roof occupying 60 m sq live-able and 35 m sq of attic.
Rest of build Block with 250 mm cavity, passive slab on 300 mm of eps.
The options open to me:
1) Roof with 50 mm air gap, 130 mm metac in rafters with a suspended counter batten underneath to accommodate 200-250 mm more insulation, than air tight membrane. (This is the engineers favored option) traditional and with air gap peace of mind with regard to rot?
2) A passive roof system from Kore with 200 mm eps sitting on a osb base over the rafter and 150 mm eps between rafters.u value of 0.10. Concern about having a non breathable insulation over and between the rafters, or is this just over reacting??
3) Roof with counter batten over the rafters/ membrane, same suspended counter batten underneath and full filled with cellulose 340 mm 60 kg giving u value of 0.11. I have spoke to a few people including my architect who thinks this is the way to go as it is breathable and will have a good decrement delay due to weight. A installer has stated that if we counter batten above the rafter and use breathable membrane we can full fill between the rafter, Is this advisable?
Finally any suggestions on sealing the wall plate junction. Been presented 2 options by engineer:
1) Isover roll seal that goes under the wall plate and is compressed to seal
2) Wrapping a membrane around the wall plate lower end sealed into inner block wall plaster and top end taped into roof inner airtight membrane.
Sorry for the length of the post but really don't know which way to turn as all options given to me "seem" to be good.