DIY Flat Roof Construction

In this DIY guide we'll go over all the basics of how to build a flat roof. From the materials to the actual installation, we'll provide an extensive step by step guide. We'll focus mainly on the EPDM flat roofing system.

The following instructions refer to how to build a flat roof of EPDM:

Tools for flat roof construction:

- Drill
- Scissors
- Paint
- Glue brush
- Seam roller
- 9" fleece type emulsion roller
- measuring tape
- tin snips
- EPDM rubber membrane
- Water-based adhesive
- Formflash EPDM
- Aluminum trim
- Sealant
- Prefabricated internal and external corners
- Adhesive cleaner

Steps:

1. Sweep deck clean and fold membrane over flat roof surface. Leave for 30 minutes to allow creases to ease out, then fold back half the membrane on itself from the center to expose half the flat roof surface.
2. Use 9" fleece emulsion roller to apply water-based adhesive onto flat roof surface for a 0.5-1mm thickness. Lightly coat EPDM membrane before applying.
3. Lift loose end of rubber and walk out to the edges in order to mate it to deck. Use a broom to brush out bubbles or creases. Use bonding adhesive for stands and edges.
4. Fold back other half of membrane over the now glued half, and repeat the above process.
5. For roof-wall joints, cut a mortar joint between brick courses 1" deep and 6" above flat roof level.
6. 6. Glue prefabricated corners over membrane in relevant areas, using rubber sealant for edges.
7. For flat roof-pitched roof joints, take up membrane 12" under tiles or slates, by removing their bottom row.
8. Use bonding adhesive to glue membrane of flat roof's perimeter edge, and then trap it by placing trims along edges. Close off open ends using tin snips.
9. Install tiler batten before fixing gutter trims, and fix gutter trims through the vertical face using sealant.