timber pitched roof/ceiling insulation underside design.

[chiefgod]

Hi,

Below is an image of the interior of our living space. I am looking to insulate with 50mm celotex or kingspan (it has tri iso on the exterior) to prevent draughts which is causing the room to be a chilly 12 degrees when it is 5 degrees outside even with the heating on max.

I would like to cover the insulation with pine or reclaimed timber but I am concerned about the expansion and contraction of the cut boards butted to the rafters. I don't really want to run beading down each side of the rafters, which would enable me to have a small gap between the new board and the rafter.

If anyone has any suggestions about a less work intensive option or design ideas it would be really appreciated.

Cheers

sorry you have to tilt your head left to see the picture properly

 

[Etienne247]

Hi,

I'm very surprised that the room is draughty if you have Tri Iso 9 or Triso 10 fitted as this is meant to be used as a continuous layer with all joints tape up, and the product taken right down to the cavity wall insulation.

Have you located the source of the draught and treated it?

How much space do you have to spare spare underneath the rafters? You could use something like Rockwool Flexi but its thermal value is lower than the celotex or kingspan boards and so you would need to put a deeper slab in.

Visit my company website: [removed]

Its a difficult one to advise on without seeing the property itself.

 

[chiefgod]

The source of the draft is where the tri iso has been left flapping in the wind on the exterior at the gutter end of the roof to apparently allow air to circulate.

The rest of the roof was taped and we have 100 mm under the sarking boards to do something with.

 

[Etienne247]

Moderator 9 - Thanks for your input.

Chiefgod - If this is the case the product has not been installed properly.

View installation instruction:
http://www.insulation-actis.com/docspdf/guideposeuk.pdf

You should not have any gaps between the edge of the product and the insulation coming up from the cavity.

Hope this helps.

 

[chiefgod]

Thanks for your help.