Flat Roof Slope Requirement

In order to achieve this drop a slightly steeper angle of 1 40 1 44 should be the aim when installing a flat roof as this accounts for surface.

Flat roof slope requirement.

The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. Asphalt shingles require a minimum roof pitch of 2 12 or greater. For metal panel roof systems with nonsoldered seams with applied lap sealant ibc 2018 prescribes a 1 2 12 minimum roof slope. A roof pitch of 6 12 26 5 or less is considered easily walkable and no extra precautions are required.

Since they vary in quality as well as method of installation the choice preferred for a flat roof will ultimately have an effect on the final slope of the flat roof. For standing seam metal roof panel systems a 1 4 12 minimum roof slope is prescribed. This 1 4 12 minimum roof slope requirement also applies to spray polyurethane foam spf roof systems in new construction. The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.

Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater. Asphalt shingles continue to be the most widely installed roof covering option in north america. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Normally 1 80 0 72 is the recommended minimum angle for a slope and this is universal across the vast majority of flat roofing systems regardless of the materials that they incorporate.

The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. Let us recap on the minimum roof pitch required for each type of roofing material. A roof of pitch 7 12 30 is manageable but caution should be taken. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

An example for a steep sloped roof is 8 12. Pitches between 8 12 and 10 12 33 40 are also considered walkable but it is not advisable and if you have to walk on these roofs extreme caution should be. Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling. In general the minimum slope for a flat roof is 1 0 but as stated earlier this is only possible in theory.

This means that the rise of the slope goes up or down 8 inches for every 12 inches. There are two types of flat roof. Cold roofs and warm roofs. In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.

Metal roof shingles require a minimum roof pitch of 3 12 or greater.