Install the purlin along the house and the outer purlin.
Pitched roof under deck.
Typical decks are designed to support 55 psf lbs per square foot.
Installing a porch roof over an existing deck is usually not recommended unless the deck was originally designed to support a future porch.
The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run.
The minimum pitch for a standing seam metal roof is 1 4 or 3 inches rise to 12 inches run.
Whenever i install decking over a roof i make sure the framing is structurally sound and properly pitched to drain water.
Lower than the purlin along the house 12 x 1 4 3.
If the span under your deck is 12 ft for example the purlin at the outer end of the deck should be 3 in.
Then stretch a string between them.
First mark all the purlin locations on the deck joists.
Once you have your beams in place everything above them joists deck boards balusters and handrails is the same as for any other deck.
Centers supported by a beam and a ledger as on most decks.
Summer calls for sultry nights under the stars and sun drenched cocktail gatherings making the backyard deck the ultimate destination this season.
For those who desire a bit more shade and privacy while soaking up the rays however a deck roof may be in order.
Roof deck framing unlike for decks at ground level doesn t entail a ledger attached to the rim joist of a house.
Porch decks require 25 additional psf for roof loads for a total of 80 psf.