Insulation Over Existing Flat Roof

Remove all existing flashing material from around vents and pipes using a pry bar and hammer.

Insulation over existing flat roof.

Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid insulation. Composite insulation works in flat and low sloped roofs with a variety of roof coverings. 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. I like rock all because of its higher r value fire and moisture resistance and good cost per r value 6.

Install roofing over a wind barrier like spun olefin. Composite insulation reduces the need for a cover board when applying different membrane roof coverings. One of the main benefits you will receive from installing a warm flat roof is condensation will not. This could be metal or roof sheathing and shingles.

The target should be to achieve a u value of 0 25w m2k or better. Fill this space completely with insulation. 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. How to install insulation board over an existing roof membrane 1.

We are insulating a flat roof with tapered rigid insulation over a moisture barrier and then capped with modified bitumen. Calculate the total square footage of the roof to determine the number of. How to insulate a flat roof warm flat roof. The typical u value of an existing uninsulated flat roof is 1 5w m2k.

However we lose r value where the taper is thinnest and need to insulate under the sheeting. Insert the pry bar. To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. The 6 inches of rigid insulation added to the top of the existing roof deck needed to be done in a manner that was invisible.

Now comes the really really big point. 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. Measure the roof with a tape measure.