Insulation Over Existing Flat Roof

The typical u value of an existing uninsulated flat roof is 1 5w m2k.

Insulation over existing flat roof.

Measure the roof with a tape measure. Install roofing over a wind barrier like spun olefin. However we lose r value where the taper is thinnest and need to insulate under the sheeting. 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. 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. Many properties use this option as there are no additional costs for scaffolding or organising how to.

I like rock all because of its higher r value fire and moisture resistance and good cost per r value 6. Fill this space completely with insulation. We are insulating a flat roof with tapered rigid insulation over a moisture barrier and then capped with modified bitumen. Remove all existing flashing material from around vents and pipes using a pry bar and hammer.

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. 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 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.

We toyed with spray foam but this may be overkill as we would have to insulate areas that don t require it. Insert the pry bar. Composite insulation reduces the need for a cover board when applying different membrane roof coverings. Make a grid frame work of 2 dimensional to make space for the insulation.

To achieve this add 100 to 160mm of insulation above the structural deck dependant upon insulant conductivity. Calculate the total square footage of the roof to determine the number of. One of the main benefits you will receive from installing a warm flat roof is condensation will not.