Flat Roof Ceiling Insulation

For a 1 inch board equivalent of 6 r value.

Flat roof ceiling insulation.

Can a flat roof be insulated from inside from the ceiling of the area below. It makes no difference which way the heat flows through it. Your two best options are spray foam insulation on the underside of the roof sheathing an installation which will require the ceiling to be removed at least partially or the installation of rigid foam on top of the existing sheathing. In fact it may cause damage in the long term.

This system was often used in the past but is not recommended nowadays. The typical u value of an existing uninsulated flat roof is 1 5w m2k. Flat roof insulation thickness the chosen insulation laid on top of this should be able to take the weight of anything put above it on the roof without compression or protected from compression by further sheeting. It is top quality and the most cost effective product for your flat roof.

It s what s called the cold roof principle. It should be of the maximum available thickness. But spray foam insulation used at the underside of the roof deck would need to be covered by a thermal barrier and intumescent coatings are commonly used. Flat roofs or low slope roofs should be unvented.

Vapor barriers are usually made from polyethylene film asphalt laced building paper or paper backed aluminum. The air pockets inside the insulation traps the heat. Insulating a roof from inside is technically feasible. You can expect to pay about 55 100 sq ft.

With flat roof insulation a vapor barrier should sit between the joists and ceiling panels and the insulation on top. Insulation is placed in between the joists underneath the roof surface. Ceiling insulation is excellent for resisting convected and conducted heat. There are two main types of flat roof that require different approaches to installation.

Insulation material is placed on top of the roof rather than in between the ceiling and the decking. For such constructions the principles and benefits of unvented attic construction are similar to that occurring in a single family residence. However in many situations the insulation may need to be primarily or entirely below the flat roof membrane and between the roof joists if so what are the best options. The correct method for a flat roof is under the current regulations to have a warm roof.

We recommend having at least 20 r value worth of material for optimal energy efficiency. While expensive the best insulation is polyiso rigid foam. As a matter of fact thermal resistance works the same way. You would only do this however if replacing the roof covering on top and you have the height above the roof to do this.