Insulating A Ceiling Under A Flat Roof

Can a flat roof be insulated from inside from the ceiling of the area below.

Insulating a ceiling under a flat roof.

I live in southern ontario canada where there are significant differentials of temperatures from summer to winter. The existing ceiling is sound but provides no insulation. I ve built a timber frame to support a new plasterboard ceiling below the existing one. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation.

Lots of traditional flat roofs are of the cold roof construction type. How to insulate a flat roof. Due to a rewire i ve had to remove parts of the plasterboard ceiling and have found that there is no insulation in the roof i can see the roof deck and joists there is no vapour layer and the plasterboard is not foil backed. This means there is a vapour control layer in the ceiling and cross ventilation at the eaves or the top of the walls.

This may help with condensation but causes such a loss of heat that it has been banned in scotland. It s what s called the cold roof principle. With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same. Insulation material is placed on top of the roof rather than in between the ceiling and the decking.

Insulation is placed in between the joists underneath the roof surface above. Cold flat roof insulation. Both these variants require different approaches to insulation which will be covered in this guide. However we lose r value where the taper is thinnest and need to insulate under the sheeting.

This could be a hole crack or other kind of unprotected space that the insulation does not cover such as around a light fixture. There is only a small gap between this ceiling and a concrete roof cold roof felt covered. Not only can. With flat roof insulation a vapor barrier should sit between the joists and ceiling panels and the insulation on top.

I want to insulate below a flat roof without removing the existing ceiling. The quest for greater energy efficiency in buildings has led to increasing interest and need for insulation improvements in hvac equipment more airtight construction new materials and assemblies. Senior engineer manager at icynene john broniek makes the case for the unvented attic assembly and why insulating the underside of the roof makes sense. Hi i have a flat roof extension built in the 1970s.

This system was often used in the past but is not recommended nowadays. We are insulating a flat roof with tapered rigid insulation over a moisture barrier and then capped with modified bitumen.