Flat Roof Insulation Slope Layout

Consider geography budget and use for the roof to determine the best option.

Flat roof insulation slope layout. R 46 unvented roof assembly two layers of r 6 5 inch rigid insulation yielding a total combined thickness of 2 5 inches. A note to consider before construction. If insulation is installed below the flat roof deck this is called a cold roof. From there the flat roof system you choose will determine the materials you apply.

Roofing insulation is one of the most important and misunderstood building components. Layers of rigid insulation have staggered joints to facilitate airtightness. Tapered backwashes can also help reduce the insulation height at the roof edge. Two layers are preferable to one layer due to increase in air flow resistance.

Re roofing usually entails different slope requirements. Cricket length points a to b generally the longer of the 2 cross sections. Because the roof slope is steeper than for flat roofs it makes much more sense to slope the roof framing in this case to follow the roof pitch. Here we share the most common mistakes people make when installing flat roofing insulation.

As a general rule if the insulation is 2 thick or less a 4 by 4 is sufficient. Cricket panel slope the slope of the cricket panel. Roof surface slope the slope that is in the structural deck the slope created by tapered insulation or a combination of the two. There is no potential for condensation until interior moisture levels exceed 45 rh at 70 f during the coldest month.

Cricket width points c to d generally the shorter of the 2 cross sections. The framing system for shed roofs is straightforward and similar to that of flat roofs. Built up roofs shall have a design slope of not less than one fourth unit vertical in 12 units horizontal 2 percent slope for drainage except for coal tar built up roofs that shall have a design slope of not less than one eighth unit vertical in 12 units horizontal 1 percent slope. To drain and insulate dead level roof decks.

Manufactured from lightweight foam control eps tapered expanded polystyrene eps roof insulation is a value engineered system that has been proven in new and reroof applications all over the country. Roof framing members can be any number of materials depending on the span. Today s variety of flat or low slope commercial roofing options roof pitches ranging from 12 to 3 12 is no longer simple and has grown considerably in the last 50 years. Tapered expanded polystyrene eps roof insulation was developed more than 30 years ago with a dual purpose in mind.

If the insulation reaches 3 or thicker an 8 by 8 creates a more gradual slope while still providing the necessary momentum. A typical interior roof drain assembly occupies about a 4 by 4 square area with a per foot tapered slope.