Installing a porch roof over an existing deck is usually not recommended unless the deck was originally designed to support a future porch.
Pitched roof under deck.
Then stretch a string between them.
Centers supported by a beam and a ledger as on most decks.
Whenever i install decking over a roof i make sure the framing is structurally sound and properly pitched to drain water.
Summer calls for sultry nights under the stars and sun drenched cocktail gatherings making the backyard deck the ultimate destination this season.
Install the purlin along the house and the outer purlin.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
A deck on a sloped roof requires a different approach to the framing underneath the joists.
Porch decks require 25 additional psf for roof loads for a total of 80 psf.
For those who desire a bit more shade and privacy while soaking up the rays however a deck roof may be in order.
Instead a pair of beams rest on supports called sill plates to create a frame for the deck.
The project illustrated here was a complete teardown and rebuild so i framed the roof with 2x8s spaced on 16 in.
Lower than the purlin along the house 12 x 1 4 3.
First mark all the purlin locations on the deck joists.
Typical decks are designed to support 55 psf lbs per square foot.
Roof deck framing unlike for decks at ground level doesn t entail a ledger attached to the rim joist of a house.