Raintight panels made of aluminum lock together to create waterproof joints.
Cheapest way to waterproof under deck.
Several commercial waterproof deck systems are available to create a dry space under a deck but rune stactic of adding a roof to a deck seems to be just as effective.
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.
For pricing and availability.
Here are the details in case you d like to build your own building a deck with a roof version.
Epdm is available in widths up to about 50 so you can generally lay down a continuous sheet without any seams.
First you need to purchase a continuous sheet of epdm which will cover the entire deck area.
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 used to provide a durable long lasting waterproof membrane on top of your existing deck.
To install this system under an existing deck cut the membrane pieces with a shallower droop no more than 4 inches and staple the membrane to the underside of the joists caulking each seam as described in the following pages.
Trex 0 25 ft deck trough.
For pricing and availability.
There are underdeck cielings systems that are available but i think the most inexpensive way would be to hang corrugated plastic or metal panels from the rafters.
Designed for contractors and diyers who want an affordable attractive and easy to install vinyl deck flooring product econodek waterproof vinyl decking is more than a deck flooring product it s also peace of mind.
How to dry in underneath a deck without the expensive underlayment or systems.
The water drains straight.
One method of waterproofing under the deck is to install a membrane.
This membrane prevents water from reaching the areas below the deck such as a roof or open area.
Screw 2x2s to the joists over the membrane as in the drawing below.
You would need to create a slant for run off and install a gutter at the end of the panels but i think you could get it to stay dry from above.
26 in x 120 in deckdrain opaque tan under deck ceiling panel.