And you will a need a metal or plastic gutter at the outer edge of the deck inside the band joist to catch the water from the troughs.
Deck membrain for gutter.
Butyl tape is applied to seal all seams.
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.
Membrane deck surfaces require a solid substrate as support.
Epdm membrane for the water to drain towards the gutter the epdm membrane has to droop between the joists to create a trough that slopes down the length of the joists to the gutter.
A piece of material stapled on the inside of the band joist in each joist bay is also a good idea to protect the band joist from water and to direct water into the gutter.
Products installed above the joist use a rubberized membrane that drapes down between each joist bay.
An under deck gutter system works perfectly as long as the material captures and diverts the water correctly.
Decking boards are then installed over the top.
The trex rainescape membrane which comes in rolls is fastened loosely to the top edge of deck joists.
The downspouts can be oriented to fit between joists spaced 12 or 16 inches on center.
Sloping the membrane so one end is lower than the other allows the water to flow to a downspout at the end of the joist.
Cd grade ply with minimum cca treatment and minimum 17 mm thick must be used.
Plywood is the most common type of substrate used and must meet the following guidelines.
Dedication to technical excellence and premium design is what makes dec tec vinyl deck membranes an unprecedented product in the vinyl decking market.
It doesn t have to look like that.
Screw 2x2s to the joists over the membrane as in the drawing below.
At the head of the joist bays usually at the ledger i allow for a 1 to 1 1 2 inch deep trough.
A revolutionary under deck drainage system uses a network of troughs and gutters to divert water from the deck shields the area below the deck from rain snow sun and other elements provides 100 protection of the deck substructure from moisture.