Ready to hire?
Post your job in minutes, browse real reviews and choose who to speak to.Post a jobNeed some tips or advice?
Ask a questionLoft Conversion
Insulating unfelted slate roof - what membrane to use (if any)?
Anonymous user 14/03/2024 - 2.32 PM
We are adding space in the loft and have put a staircase in. Underside of roof is visible and in ok condition. We are putting 500mm foil backed insulation boards in between 1000mm rafters and leaving an airgap. Dwarf walls are also getting same insulation and rockwool is already in place under joists. The idea is then to plasterboard over, however do we need a sheet/membrane over boards+bottom of rafters before we plasterboard? We are also inserting a Velux window. We have in mind to lift slates and install felt at some point...... Novice
Are you a tradesperson and able to answer this question?
1 Answer
Anonymous user
To do the job properly you should take off the slates, re felt using breathable felt re batten and tile. You should insulate between the rafters with 100mm of celotex. Batten down the rafter to ensure a 25mm air gap. Use foil backed plaster board the board over.
Answered27 February 2014
2