A flat roof can give any home a distinctive and even minimalist look, and modern architects often choose to incorporate a flat roof. Most roofs are not actually completely flat, as that would mean that water would collect and eventually seep into your home; rather, they have an incline of at least an eighth of an inch for every foot.
Make sure you have the supplies and tools that you will need for this project, before starting. They include 5/8 inch plywood sheathing, 2 x4s, steel washers and screws, a tape measure and glue. You should also have on hand gravel stop, tri-polymer caulk, strips of uncured rubber, an ISO board, termination stops and a special rubber collar.
Constructing Your Flat Roof:
Constructing The Incline
Molding the 2x4s into long wedges and then nailing them into the joists will create the incline for your roof. To help ensure that your roof is strong enough to support a heavy fall of snow, the wedges should be placed closer together than those used on a sloping roof.
Adding The Plywood
So that you have the option of expanding your roof at some point in the future, use the 5/8 inch plywood sheathing, leaving a gap of 1/8 inch at the joints. The sheathing should be placed on top of the wedges nailed into the joints.
Installing The Underlayment
Using the galvanized steel washers and screws, anchor the ISO board to the plywood sheathing. As the rubber will then go on top, the ISO board ensures a protective base.
Creating the corners is the next step in flat roof construction, and this is achieved by using a table saw to cut the 2x4s lengthways on a 45 degree bevel. These should then create a gradual transition when they are screwed into place between the wall and the roof. Once complete, apply rubber roof material to the sheathing, ensuring that the material runs up the walls.
Gluing The Rubber
Dry fit the rubber on the roof, after sweeping away any dirt or debris. Once you are satisfied with the fit you can use a basic utility knife to cut it into the required lengths, making sure to account for any chimneys or other fixtures. After removing the rubber, use a 14 inch nap paint roller and extension to apply glue to the underneath of the rubber and the exposed ISO layer.The rubber can be fitted over the ISO board once the glue feels dry to the touch and any air bubbles that remain after gluing the rubber down can be smoothed out with a dry roller.
On the seams of the rubber EPDM, glue one foot lengths of uncured rubber. Any vent pipes can be wrapped with a special rubber collar, and the tri-polymer caulk used to seal the lengths of uncured rubber.
To prevent walls from peeling, you should screw metal brackets, or termination stops to the vertical sections. The final tasks in your flat roof construction are to nail a gravel stop, or galvanized drip edge over the roof's front edges and use tri-polymer caulk to seal the brackets.
About the Author Greg works with Majestic Roofing. Majestic Roofing is one of the most reliable roofing contractors Oklahoma City has.