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.
Deck membrain for gutter.
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.
Membrane deck surfaces require a solid substrate as support.
Products installed above the joist use a rubberized membrane that drapes down between each joist bay.
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.
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.
Screw 2x2s to the joists over the membrane as in the drawing below.
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.
The underdeck ceiling system can turn the ugly space under your deck into an outdoor haven that s dry bright clean and enjoyable without costly reconstruction.
Decking boards are then installed over the top.
Plywood substrate and timber deck joists must have a maximum moisture content of 20.
The downspouts can be oriented to fit between joists spaced 12 or 16 inches on center.
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.
What makes the underdeck ceiling so innovative is its simple and efficient system of vinyl gutters and panels which attach underneath the deck.
The trex rainescape membrane which comes in rolls is fastened loosely to the top edge of deck joists.
At the head of the joist bays usually at the ledger i allow for a 1 to 1 1 2 inch deep trough.
It doesn t have to look like that.
Cd grade ply with minimum cca treatment and minimum 17 mm thick must be used.
Butyl tape is applied to seal all seams.