FLAT ROOF INSULATION

[Wheels]

We have recently bought a 1970's dormer bungalow and have replaced the flat roofs. Whilst doing this we noticed the insulation was very poor so we are going to replace it. The flat roofs are 100mm deep and we can't lower ceilings because of position of the windows. What is the best means of insulation for both sound and heat (at the moment we can hear the birds on the roof) and can anyone tell us if we can fill the cavity or do we need to leave a gap.

 

[chappers]

depends on what type of roof you have you can create a warm roof by completely filling the void and then covering under your joist with a vapour proof membrane or foil backed plasterboard, to prevent moist air entering the roof space and condensing under your roof deck or you can leave an air gap above your insulation provided there is some sort of ventilation to the outside at the eaves to carry the moist air away. Your best bet is to use a blown slab insulation such as ceotex, but with only 100mm you will not be able to meet current building regs, but I'm sure it would be an improvement on whats already there.