How to Convert a Low Slope Tar & Gravel Roof to a Green Roof

Use the ladder to climb onto the roof. Lay out the rubber sheets vertically down the slope of your roof. Place sealant tape on the underside of the sheets and press them into the roof to hold them in place. Slightly overlap each new sheet with the one next to it by 2 to 3 inches. Cover your entire gravel and tar roof with the rubber sheets. This is the watertight layer so your roof won't leak.

Sprinkle a 1-inch thick layer of gravel over the rubber sheets to provide better drainage for the roof and the plants. Spread the gravel over the entire roof.

Mix equal parts wood chips, pumice and vermiculite together to create the soil layer for your green roof. Mix enough soil to cover your roof in a 4- to 6-inch layer. Pour the soil mixture onto the roof and even it out with a rake.

Select plants from the species Sedums, Delosperma, Sempervivum, Dianthus, Thymus and Alyssum for roofs with soil at least 4 inches deep. Festuca grass can be grown on roofs with a 6-inch layer of soil as well.

Dig shallow holes for the plants as deep as the root balls and twice as wide. Place the plants in the holes and fill them with the soil mix. Space plants about 2 to 3 feet from each other.