Insulating Attic Room Under Slate Roof

I would advise as much insulation between the rafters as you can get in but leaving a 25mm gap and another 40 or 50mm continuous layer beneath the rafters.

Insulating attic room under slate roof.

This construction approach was first used in the 1970s and it has been implemented much more widely since it was first included in the international code council s icc model building code in 2007 irc section 806 4. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. Install wood between the rafters maintaining a 1 gap between the wood the underside of the roof deck. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

Box out light fixtures. Most codes require a specified minimum amount of headroom and it s tough to meet this requirement when insulating a finished attic especially since most. You may have to build out on the inside a bit to get enough insulation. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.

The gap should be on the cold side of the insulation. Then use spray foam insulation after that finish the ceiling how you would like. Insulating in and around your roof attic space also prevents long term damage from moisture build up or ice damming which results from the warm air trying to escape through the apex of the roof but instead heating up the snow. Normally it would be 50mm but if you have no undertile felt then 25mm would be reasonable.

To meet all three goals insulating your finished attic ventilating the roof and maximizing headroom use a combination of dense batt insulation rigid foam sheeting and air chutes.