Under Deck Roof Pitch

To solve this problem you can either replace your original deck footings to support your new roof or build your roof separate from your deck to ensure a proper foundation.

Under deck roof pitch.

Attach the horizontal beam by using a nail gun. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. 10 foot deck 10 4 2 5 round down to a whole number. First mark all the purlin locations on the deck joists.

Then stretch a string between them. Find under deck ceiling systems at lowe s today. Minimum slope is 1 4 inch vertical in 12 units 2 slope and ideally 1 2 vertical in 12 units 4 slope. If the span under your deck is 12 ft for example the purlin at the outer end of the deck should be 3 in.

Make a cutting on one of the sides of the horizontal roof beam on an angle. While a typical deck is designed to support 55 pounds per square foot psf a roof requires 80 psf of support. For a house roof the recommended minimum slope is 2 5 vertical inches for every horizontal foot but a nearly flat roof is fine for under deck installations. Among the newest is the raintight system introduced at deck expo 2014.

If you consider it as similar to a roof than according to code. The first rail is 1 2 and is placed 4 feet from the house. Add 1 2 to the pitch rail height at each 4 foot increment. Raintight panels are made of heavy gauge aluminum.

However you can only use this pitch with built up roofing or specialized synthetic roofing. What makes the underdeck ceiling so innovative is its simple and efficient system of vinyl gutters and panels which attach underneath the deck. This is for metal roofs that have a sealant between their lapped seams. Measure the depth of the deck and divide the total in feet by 4 since a pitch rail is needed every 4 feet.

After that to make it flush with the roof of the existing house cut the two outer rafters. Install the purlin along the house and the outer purlin. Step 2 install a wood support structure for your panels screwing a row of 2 by 4s running parallel to your wall every 2 feet along the underside of your deck. Under deck ceilings a number of recently introduced under deck ceiling systems use corrugated aluminum or plastic panels designed to catch water that drains through decking and channel it away from the area below.

You have to do it thoroughly so that the rafters sit flush on it.