DIY Network

Sloped/Waterproof Roof Construction How to slope and waterproof an existing roof From "DIY to the Rescue" episode DTTR-606

The crew begins the rescue by giving a flat roof a declining slope, and then waterproofs it.

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	Figure A
	Figure B
	Figure C
	Figure D
	Figure E
	Figure F
	Figure G
	Figure H

Materials:

measuring tape
chalk line
circular saw
decking material (oriented strand board)
galvanized roofing nails
nail gun
aluminum flashing
standard roofing nails
synthetic rubber sheeting
contact cement
paint rollers
utility knife

Sloped/Waterproof Roof Construction

1. The deck must first be cut on the front and at the joists to allow for a slope. As a general rule, your slope should be about a 1/4 of an inch per foot. (This deck is 10 feet, so the slope was 2-1/2 inches.)

2. Cut down the face board using the pitch line as your guide. Using a circular saw, remove the 2-1/2 inches that will give the new roof a declining slope. By cutting this board first, you have an accurate guide for cutting down each of the perpendicular joists (figure A).

3. Again, using the trimmed front board as a guide, snap a pitch line along each joist from the house end down to the front board (figure B). Continue this process until all the joists have been trimmed (figure C).

4. Once all the joists have been trimmed, install the roof decking, which in this case, is made up of oriented strand board (figure D). Start by laying the first board parallel to the house; groove in, tongue out.

5. Using galvanized roofing nails, face the boards to the joists below, nailing every eight inches or so. Make certain the flat ends always land on a joist so they can be nailed down securely (figure E).

6. Install the end joints of each adjacent panel with a minimum spacing of 1/8 inch between them to allow for expansion and contraction (figure F).

7. Once all the panels are nailed in (figure G), the next step is applying the aluminum flashing, all the way around the roof. Using standard roofing nails, attach the strips of aluminum flashing directly to the new roofing material (figure H).

8. After the flashing is applied, waterproof the area with a single sheet of synthetic rubber (figure I). Roll this out evenly covering the entire surface and then trim it to size before gluing down.

9. After making sure the rubber is positioned evenly along the front edge and it has been smoothed out completely, the rubber is ready to be attached to the roof.

10. First, fold half of the sheet back onto itself (figure J).

11. Next, using stand paint rollers, apply contact cement directly to the roof and the flashing (figure K).

12. After 15 minutes the cement will become tacky and the rubber can be rolled back out over the roof. Smooth out any bubbles or kinks as you go (figure L).

Figure I

Figure J

Figure K

13. Repeat the process on the other half and trim up the outside edges (figure M).

14. The roof is complete (figure N).

Figure L

Figure M

Figure N

DIY Decks For more information on everything related to your deck, visit DIY Decks.

RESOURCES :

Advantech Flooring and Sheathing
Website: www.huberwood.com

FYPON
Website: www.fypon.com

Little Giant Ladder Systems
Website: www.littlegiantladders.com

HITACHI Power Tools
Website: www.hitachi.com

Porter Cable Power Tools
Website: www.deltaportercable.com

Delta Power Tools
Website: www.deltaportercable.com

Klein Tools
Website: www.kleintools.com

Gladiator Garageworks by Whirlpool
Website: www.gladiatorgw.com

Benjamin Moore Paint
Website: www.benjaminmoore.com