As a result most decks have inadequate footings to support a new porch roof.
How to build a waterproof deck roof.
There are a few things that make pvc decking different in regards to roof decks.
How vinyl waterproof decking benefits roof decks.
This is used to provide a durable long lasting waterproof membrane on top of your existing deck.
Currently about 10 of our projects include a dry space under the decking either in part or under the entire decking surface.
Frame up a box the size of the outer dimensions of your deck using 2 by 4 inch lumber.
The drainage system flashing details and waterproofing membrane that go over the structural deck are the key to success.
First it s designed to be waterproof and walkable whereas most other flat roof materials are not.
A perimeter frame and graduated spacer nailers are fastened beneath the deck joists so that the plane of the ceiling slopes slightly at least 1 4 inch per foot away from the house toward the joist header.
Epdm is available in widths up to about 50 so you can generally lay down a continuous sheet without any seams.
Build the frame of the roof on the ground.
Step 2 cover the deck.
Cover furniture or items on your flat roof deck that are not meant to be waterproofed with the drop cloth.
Deck framing needs to be sloped with at least a 1 8 inch per foot pitch for drainage a consideration when you re retrofitting an existing deck with a waterproof decking product.
The most common approach is to use a heavy gauge epdm membrane typically 60 mil as the roofing membrane usually placed over rigid insulation.
The footings for porch decks must be larger than deck footings.
First you need to purchase a continuous sheet of epdm which will cover the entire deck area.
Make sure it s free of all dirt and debris.
Many porches use 22 diameter corner and intermediate.
Typical decks are designed to support 55 psf lbs per square foot.
Then run joists connecting the front of your roof with the rear every two feet along the length of your roof.
That s unfortunate because building a reliable long lasting waterproof deck over living space is relatively straightforward when the best practices and materials are used.
Materials required fiberglass panels gutter and downspout pressure treated 2x4s roofing screws.
There are a number of icc es listed manufacturers of class a walking deck systems see class a fire resistant walking and roof deck systems sidebar.
Any dirt and debris will keep your waterproofing sealer from sticking to the lumber.
Porch decks require 25 additional psf for roof loads for a total of 80 psf.
