Insulation Over Existing Flat Roof

Fill this space completely with insulation.

Insulation over existing flat roof.

Composite insulation works in flat and low sloped roofs with a variety of roof coverings. The target should be to achieve a u value of 0 25w m2k or better. How to install insulation board over an existing roof membrane 1. This could be metal or roof sheathing and shingles.

However we lose r value where the taper is thinnest and need to insulate under the sheeting. To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. I like rock all because of its higher r value fire and moisture resistance and good cost per r value 6. Remove all existing flashing material from around vents and pipes using a pry bar and hammer.

We are insulating a flat roof with tapered rigid insulation over a moisture barrier and then capped with modified bitumen. Many properties use this option as there are no additional costs for scaffolding or organising how to. Insert the pry bar. 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.

The typical u value of an existing uninsulated flat roof is 1 5w m2k. Measure the roof with a tape measure. Make a grid frame work of 2 dimensional to make space for the insulation. Composite insulation reduces the need for a cover board when applying different membrane roof coverings.

Calculate the total square footage of the roof to determine the number of. Install roofing over a wind barrier like spun olefin. The rigid foam can be installed over new sheathing coated with an integrated water resistive barrier as shown in figure 1 or the insulation can be installed over the existing roof sheathing which is first covered with a fully adhered air control membrane that extends up the parapet sides above the flat roof as shown in figure 2. Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid insulation.

Now comes the really really big point. How to insulate a flat roof warm flat roof. One of the main benefits you will receive from installing a warm flat roof is condensation will not.