5 Types of Flat Roof Insulation

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Flat roof insulation is an important component to your home as it helps maintain temperatures within the home while preventing air from escaping. Flat roof insulation is very important in this style of roof because snow and water (as well as ice) can all sit on the roof for a long time. With the proper insulation, the cold, moisture, and even the sun will not penetrate the roof.

A flat roof has several layers to it which include a vapor control layer followed by a thermal layer that acts as the insulation layer of the roof. It is designed to trap air and there are several kinds of materials that work well to do insulate the roof. All insulation has an R-value assigned to it, which is the amount of thermal resistance that the insulation has. The higher the R-value, the more effective the insulation. The article that follows will share with you several types of flat roof insulation and their R-values.

1. Wood Fiber

If you are looking for an organic alternative to flat roof insulation, then wood fiber insulation may be your best decision. This insulation is made out of purely organic wood fibers and it is formed into wood boards by mixing the fibers with various fillers and binding materials. The water resistance can be increased by having a layer of asphalt painted on the boards or used inside the fibers. The R-value of wood fiber insulation is measured at around 2.78 per inch. Wood fiber flat roof insulation is not the best choice for most situations but is inexpensive.

2. Perlite

This flat roof insulation has the same thermal resistance as wood fiber, making it just as effective and inexpensive. Perlite is a kind of glass that is made from volcanic ashes that have been pressed and refined. The perlite is combined with other organic fibers and binders, and pressed to form a board. Air bubbles are trapped inside the perlite and it is these air bubbles that create the insulation for the flat roof. To add to the natural qualities of the perlite board, they are painted with an asphalt coating. The asphalt also limits moisture absorption.

3. Polystyrene

You will find this insulation in either expanded or extruded types. Expanded polystyrene flat roof insulation is comprised of polystyrene that is combined with a foaming agent. This insulation expands when it is exposed to heat and boasts an R-value of 3.8. Extruded polystyrene flat roof insulation has a R-value of 5.0 and is created in several steps. The polystyrene is heated and then exposed to the atmosphere. It is then expanded.

4. Glass Cells

This type of insulation has a rating of 4.69, making it a good choice. It consists of glass that has been crushed and then heated while inside a mold.

5. Polyisocyanurate

This is the best flat roof insulation for the money, with an R-value of 6.0. This insulation is placed between non-organic and organic felt. Pentane is then used to expand the foam which leads to this insulation’s high rating.