How to Install Pavers Over an EPDM Membrane

Prepare your area. For patios, excavate dirt deep enough for the pavers, a base of compacted gravel and several inches of sand. For a deck, make sure the structure is sturdy enough for the weight of the pavers and a 1-inch layer of sand. A deck may require computer calculations or professional help to determine weight loads. Both patio and deck need slight slopes for drainage.

Install a foundation for the pavers. For a patio, this is a layer of gravel, compacted with a hand or mechanical tamper. For a deck, lay decking, usually oriented strand board (OSB). Both need edge treatments. For a patio, put down your gravel first, then border the area with metal or plastic edging. A deck will need curbing around the sides and flashing where it abuts a house wall.

Lay down an EPDM membrane. Spread the membrane over the entire area, overlapping at the edges. Overlap seams and seal them with EPDM tape or contact cement. In a patio, let the membrane curl up the edging. On a deck, pull it down over the edge and secure it with some metal edging; at a wall, run the EPDM up under the house sheeting, then cover it with metal flashing. It should be water-tight.

Spread polymeric sand and lay the pavers. Use 3 to 5 inches for a patio and 1 inch for a deck. Level the sand with a 2-by-4-inch board pulled across it. Lay the pavers, starting at the high end and working across and downward. Use a string guide or level to make sure you maintain the proper depth and angle. Leave slight gaps between pavers.

Finish with sand. Complete the project by sweeping polymeric sand in the paver gaps. On a deck, install some drain ports, where curbing is removed to permit water to flow out; the curbing is replaced with a geotextile material to hold the sand.