While a typical deck is designed to support 55 pounds per square foot psf a roof requires 80 psf of support.
Under deck roof pitch.
If the span under your deck is 12 ft for example the purlin at the outer end of the deck should be 3 in.
Find under deck ceiling systems at lowe s today.
Then stretch a string between them.
The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
What makes the underdeck ceiling so innovative is its simple and efficient system of vinyl gutters and panels which attach underneath the 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.
Make a cutting on one of the sides of the horizontal roof beam on an angle.
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.
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.
The slope or pitch of the under panels can be at any degree that will shed the water.
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.
This is for metal roofs that have a sealant between their lapped seams.
Add 1 2 to the pitch rail height at each 4 foot increment.
If you consider it as similar to a roof than according to code.
Minimum slope is 1 4 inch vertical in 12 units 2 slope and ideally 1 2 vertical in 12 units 4 slope.
Lower than the purlin along the house 12 x 1 4 3.
Raintight panels are made of heavy gauge aluminum.
The underdeck ceiling system can turn the ugly space under your deck into an outdoor haven that s dry bright clean and enjoyable without costly reconstruction.
First mark all the purlin locations on the deck joists.
The first rail is 1 2 and is placed 4 feet from the house.
You have to do it thoroughly so that the rafters sit flush on it.
10 foot deck 10 4 2 5 round down to a whole number.
After that to make it flush with the roof of the existing house cut the two outer rafters.
However you can only use this pitch with built up roofing or specialized synthetic roofing.
Install the purlin along the house and the outer purlin.