Residential Wood Frame Flat Roof Details

Traditional homes often have sections of flat roof over shed dormers above porches and garages and on balconies.

Residential wood frame flat roof details.

Load bearing or primary structure usually constructed in timber in a residential construction. A big percentage of homes we build in the southwest nm az have flat roofs. Wood construction data 1. The construction of the flat roof is similar to that of the timber upper floor.

Conventional light frame wood structures may be built without the need for engineering analysis of each component. Within limitations which include among others building size roof pitch and design loads the allowed span for conventional rafters can. But flat roofs take a pounding from harsh weather which is why they rarely last as long as a good sloped roof. They are designed with open web trusses with slope.

This is known as prescriptive framing. Such methods use a 4 foot design module which governs a 16 inch spacing of joists studs rafters. The provisions for prescriptive roof construction are found in chapter 8 of the irc and in section 2308 of the ibc. Flat roofs are always built at a slight incline at least 1 8 inch per foot.

Some roofs actually slope in several directions ensuring optimal water runoff. This will help you create a flat roof framing plan. The first approach to achieving a strong durable struc ture involving economical use of materials is to follow a basic modular plan for layout and attachment of framing members. Normally we use 7 16 osb roof sheathing and bituminous roof membrane torch applied vents in the parapet walls and netted blown insulation.

And their horizontal lines abound in the west and in urban areas. You can do this with a foam layer that exactly fits your roof. A literature review was conducted and supplemented with new research on the performance of conventional roof systems and components including ceiling joist to rafter connections and roof framing to wall connections. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls.

Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board. When framing a flat roof you will need to create a slight incline. From there the flat roof system you choose will determine the materials you apply. Details for conventional wood frame construction.