Attic insulation

Pinoy adventure

Hi

recently got a ber done and they recommended updating/upgrading the attic insulation.

the timbers on the floor are 100mm as well as the rafters.

we will put a t&g flooring down afterwards.

would it be best too increase the timbers too 150mm which would increase the thickness off the insulation ??

would rolls of insulation be better than sheets for both floors and rafters ??

thanks

Tim Robbins

https://www.boards.ie/discussion/2058314088/attic-insulation

You can this leg things to attach to the wooden rafters and then heighten the floor

MicktheMan

Op, why are you insulating between the rafters?

Pinoy adventure

https://www.boards.ie/discussion/comment/121189556#Comment_121189556

Too keep the attic warm in cooler months.

MicktheMan

https://www.boards.ie/discussion/comment/121189694#Comment_121189694

Unless you are living in the attic then this is a waste of time and won't work to boot because of the need to ventilate the attic space. It would appear that your thermal envelope is your attic floor and this is where you ought to be concentrating your insulation upgrade efforts.

Pinoy adventure

https://www.boards.ie/discussion/comment/121191601#Comment_121191601

We have got Velux window installed as well as 2 roof vents fitted which should cover the ventilation concerns.

we are now in the process of insulating the rafters which will be boarded over and plastered afterwards.

once that’s done we will tackle the floor and removal of the old insulation.

https://www.boards.ie/discussion/comment/121307739#Comment_121307739

Spot ventilation will not keep your rafters dry, you need continuous eves ventilation or condensation in the winter will be an issue.

You have chosen a poor strategy which will cost more for worse results, if you get the detailing wrong you put your roof structure at significant risk. The simpler approach is better.

Better to create raised platforms for storage and foot access and insulate on the floor. A continuous sheet of up to 30cm with two layers laid in alternate orientations is the right choice. If possible incorporate a vapour barrier below and on top to stop air migration (which carries heat and water vapour).

What you propose to do needs to be performed by an insulation expert who understands the critical detailing.