Insulation Over Existing Flat Roof

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.

Insulation over existing flat roof.

The typical u value of an existing uninsulated flat roof is 1 5w m2k. One of the main benefits you will receive from installing a warm flat roof is condensation will not. Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid 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.

To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. Install roofing over a wind barrier like spun olefin. We toyed with spray foam but this may be overkill as we would have to insulate areas that don t require it. I like rock all because of its higher r value fire and moisture resistance and good cost per r value 6.

Make a grid frame work of 2 dimensional to make space for the insulation. Measure the roof with a tape measure. How to insulate a flat roof warm flat roof. Remove all existing flashing material from around vents and pipes using a pry bar and hammer.

Composite insulation reduces the need for a cover board when applying different membrane roof coverings. Many properties use this option as there are no additional costs for scaffolding or organising how to. This could be metal or roof sheathing and shingles. 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.

Fill this space completely with insulation. How to install insulation board over an existing roof membrane 1. 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. Insert the pry bar.

The target should be to achieve a u value of 0 25w m2k or better. Now comes the really really big point. However we lose r value where the taper is thinnest and need to insulate under the sheeting.