Attic Insulation

BnA

I am going to set about insulating the attic in my self build in the next week. Just wanted to run by yourselves what ye thought of the plans.

The house is a 1 and a half story with Precast Ceilings. There are no Dormers upstairs, just Velux windows.

The main insulation that I am concerned about is the roof.

I was planning to fit 100mm Rafterloc (http://www.xtratherm.com/products/thinrrafterlocirl.php) or a similar Quinn/Kingspan product between the rafters.

Then I was planning on fitting 50mm Insulated Plasterboard onto the underside of the rafters.

One or two questions

What do ye think in General...?

Should I use some kind of tape to seal between the rafterloc and the rafters ?

Should I run the rafterloc down to the wall tie, or should I run it as far as the top of the Dwarf wall, and then down that ?

Thanks in advance

AckwelFoley

run it down the wall and then across the ceiling part of the house out to the wall plate

You want to insulate the areas of the house you are heating and not the vacant attic space, so insulate where ther would be heat loss into the attic from the habitable areas

teepee

Why dont you look into getting the air tightness done on it , i miss out on it :eek: . seal the house from draughts ect .

fitzie79

hi - we have something similar to yourself. we half a bungalow with rooms upstairs and no dormer windows but velux instead. we have rafterlock in the walls of the rooms upstairs with 50mm drylining slabs (along the side wall and up the slant to the ceiling). In the ceiling of the rooms downstairs which are below the unused attic space we have 300mm of rockwool.

I agree with the other poster - worth getting an airtightness test done to prevent any draughts

BnA

Thanks for the replies lads.

I agree RE running the insulation down the roof and then down teh dwarf wall. But I am not sure will I gan anything running it along teh floor of teh "dead" attic space to the wall plate considering that we have a precast concrete ceiling. Would I really gain much by leaving a bit of insulation down on it ?

Also, on the insulation itself, I was considering using 2 products from Aeroboard in Limerick. Aerodorm Platinum from Aeroboard (http://www.aeroboard.ie/roofproducts.html) and 60mm AeroGyp (http://www.aeroboard.ie/wallproducts.html) as the Insulated Salb. Has anyone ever used these before ?

Thanks Again

sydthebeat

BnA wrote: »

Thanks for the replies lads.

I agree RE running the insulation down the roof and then down teh dwarf wall. But I am not sure will I gan anything running it along teh floor of teh "dead" attic space to the wall plate considering that we have a precast concrete ceiling. Would I really gain much by leaving a bit of insulation down on it ?

Also, on the insulation itself, I was considering using 2 products from Aeroboard in Limerick. Aerodorm Platinum from Aeroboard (http://www.aeroboard.ie/roofproducts.html) and 60mm AeroGyp (http://www.aeroboard.ie/wallproducts.html) as the Insulated Salb. Has anyone ever used these before ?

Thanks Again

these are questions you need to be putting to your certifying engineer / architect. He / She needs to check if the amount of the material complies with regulations.

Scorpio Girl

hi, just looking for some advice here.
i have a bungalow with the provision to put rooms upstairs.
i bought insulation, the horrible stuff that makes you itchy that comes in rolls. some of the attic was done but when i made enquiries i was told that before i can put the insulation in i have to put timber between the felt and the insulation and then buy plastic to go over the insulation.
i'm just wondering:
a. is it true about having to put the timber between felt and insulation
and
b. if it is would i be aswell selling it on and buying the boards that are insulated, the kingspan ones that i can cut to size cos there's no way i'll get 8 * 4 slabs up the stira!

i'm not in a position to convert the upstairs yet.

Joseften

I have recently had my attic insulated by a new type of insulation in Ireland. Foam spray insulation it has made a major difference to my home the guys who installed it sprayed it between my rafters and sealed up the attic stopping all the heat loss through the ceiling might be woth having a look <snip> they are a global company I think. hope this is of use!

Mod edit: The link did not work, but any recommendations should be sent via PM and not posted on the thread.

RKQ

Scorpio Girl wrote: »

hi, just looking for some advice here.
some of the attic was done but when i made enquiries i was told that before i can put the insulation in i have to put timber between the felt and the insulation and then buy plastic to go over the insulation.
i'm just wondering:
a. is it true about having to put the timber between felt and insulation
and
b. if it is would i be aswell selling it on and buying the boards that are insulated, the kingspan ones that i can cut to size cos there's no way i'll get 8 * 4 slabs up the stira!

i'm not in a position to convert the upstairs yet.

I assume your advisor is referring to the need to maintain 50mm air vent gap between the underside of the felt and the new insulation. This is on the "slope" of the roof only and is required by Building Regulations. Some people use wood to maintain the gap while others use plastic string stapled diagonally in a zig zag between rafters.

a. Yes.

b. Personal choice. I'd use the fibre glass vertically in the walls and horizontally in the floor and ceiling. I prefer Kingspan or Xtratherm in sloping roof as it can be "friction" fitted tightly between rafters.

Realistically if you are not converting the attic, then insulate the floor only.