Hi,
I've decided to insulate the sloping roof of my garage so that I can use it as a workshop. As there is already roofing felt under the tiles I plan to leave a 2cm ventilation gap then rigid insulation between the rafters and plasterboard over the whole lot so that I can paint it. From the information I've found so far on the internet it appears I need a vapour resistant layer thrown in to the mix. I believe it should go in between the plasterboard and the insulation and should have no holes in it to let any vapour through.
1) Does this mean any overlapping layers need to be sealed and will bodge tape be sufficient?
2) What about ventilation at the very top of the room? As I see it there will be plenty of ventilation on the outside (insulation side) of the plastic but, if the room is to be completely sealed, none at the apex of the room inside. I don't think this will matter as condensation only occurs when it meets a cold surface and as it would be on the inside on the insulation the plastic should be warm. Is this true?
3) Also I have a budget to consider. I have been looking at Wicks own 50mm thick batons at 28.99 for 7.2 square metres. If anyone can suggest any types/brands of insulation that will do the job more cheaply please let me know.
Any help would be very much appreciated.
Thanks
Jo
I've decided to insulate the sloping roof of my garage so that I can use it as a workshop. As there is already roofing felt under the tiles I plan to leave a 2cm ventilation gap then rigid insulation between the rafters and plasterboard over the whole lot so that I can paint it. From the information I've found so far on the internet it appears I need a vapour resistant layer thrown in to the mix. I believe it should go in between the plasterboard and the insulation and should have no holes in it to let any vapour through.
1) Does this mean any overlapping layers need to be sealed and will bodge tape be sufficient?
2) What about ventilation at the very top of the room? As I see it there will be plenty of ventilation on the outside (insulation side) of the plastic but, if the room is to be completely sealed, none at the apex of the room inside. I don't think this will matter as condensation only occurs when it meets a cold surface and as it would be on the inside on the insulation the plastic should be warm. Is this true?
3) Also I have a budget to consider. I have been looking at Wicks own 50mm thick batons at 28.99 for 7.2 square metres. If anyone can suggest any types/brands of insulation that will do the job more cheaply please let me know.
Any help would be very much appreciated.
Thanks
Jo
