Insulating A Flat Roof From Outside

Unfortunately too many dwellings suffer from this problem.

Insulating a flat roof from outside.

Cold roof a very bad idea. You would only do this however if replacing the roof covering on top and you have the height above the roof to do this. Many properties use this option as there are no additional costs for scaffolding or organising how to gain safe access to the roof exterior. With this kind of roof the insulation follows the slope of the roof.

Whatever new flat roof covering you choose epdm rubber kemper. Or insulate partially on the exterior side of the roof sheathing with an air control layer insulate in the rafters bays control the vapor diffusion and re work the fascia soffit etc. The correct method for a flat roof is under the current regulations to have a warm roof. Not cheap but needs to be done right either way.

The material that works best depends largely upon preference in a given situation. Warm deck flat roof insulation is now the standard way to insulate a flat roof click to enlarge flat roofs for example on extensions bathrooms and dormer windows are not the best of ideas. Fur down the rafters for more r value after evaluation air seal insulate and control the vapor diffusion. Reduce extreme temperature fluctuations inside your home.

Use rigid foam insulation panels on your flat roof before applying the final roof covering or inside the house before adding sheetrock or paneling. Materials used to make insulation in these three types include mineral wool fiberglass cellulose fiber vermiculite styrofoam polystyrene and polyurethane. The insulation material is placed between the supporting joists leaving a gap of 50 60mm between the roof and insulation. Insulated roof assemblies can be vented or unvented.

They lose loads of heat and are prone to leaking causing the materials to deteriorate. I explain problems with insulating a roof using the warm and cold roof construction methods. A roof over a vented unconditioned attic does not need to include any insulation. Cold roof systems are highly inadvisable as insulation from the inside will inevitably lead to the formation of condensation.

Like other roofs insulating a flat one requires ample ventilation a vapor barrier and sealed bypasses. To produce a hot roof rigid insulation is fitted outside above the weatherproofing. In a nutshell you would sandwich 130mm of solid insulation between two decks allowing to place a vapour barrier on top of the first deck. Rigid foam panels are available in thickness.

When you have an un insulated roof you have to live with. This is then covered with a further weatherproofing layer.