Attic Insulation

bren1916

Hi,

Should my attic conversion be insulated outside of the 'room' i.e. At the bottom of the rafters and between joists? I'm aware I need 50mm ventilation at rafter level for airflow but I'm talking specifically about the storage areas outside of the room at each side, under the eaves.

Thanks for your help,

Bren.

Gumbo

bren1916 wrote: »

Hi,

Should my attic conversion be insulated outside of the 'room' i.e. At the bottom of the rafters and between joists? I'm aware I need 50mm ventilation at rafter level for airflow but I'm talking specifically about the storage areas outside of the room at each side, under the eaves.

Thanks for your help,

Bren.

Lots of different opinion s on this.
I like the idea of insulating the rafters right down to the eaves, linking it into the insulation in the walls if possible and essentially creating a warm space in the storage behind the dwarf walls. This allows for your water tank to be placed within the thermal envelope and less risk of freezing etc.

bren1916

kceire wrote: »

Lots of different opinion s on this.
I like the idea of insulating the rafters right down to the eaves, linking it into the insulation in the walls if possible and essentially creating a warm space in the storage behind the dwarf walls. This allows for your water tank to be placed within the thermal envelope and less risk of freezing etc.

My thoughts exactly, especially since without the insulation continued down the rafters to eaves level - the storage area would effectively be in a cold area and the likelihood of draughts behind the access doors would increase substantially.

Just wondering what benefit not running insulation might possibly be?

MicktheMan

kceire wrote: »

Lots of different opinion s on this.

Yes, and here's another one.:)
Insulate between the joists as this is also the ceiling of the space underneath. No point in insulating between the rafters in the crawl space, it is of no benefit.

Gumbo

MicktheMan wrote: »

Yes, and here's another one.:)
Insulate between the joists as this is also the ceiling of the space underneath. No point in insulating between the rafters in the crawl space, it is of no benefit.

Mick, would you insulate between the joists across the whole floor or just in the crawl space?

MicktheMan

kceire wrote: »

Mick, would you insulate between the joists across the whole floor or just in the crawl space?

Just the crawl space generally... but you must cut off the air passing from the crawl space to under the floor. This can be achieved by continuing the air tight layer of the dwarf walls down to the to the ceiling and joists of the room underneath. However, this is just one aspect of converted attics and dormers which is frequently overlooked leading to cold spaces in winter and hot in summer.