Flat Roof Framing Methods

Stick truss roof framing.

Flat roof framing methods.

Platform and balloon frame construction. The flat roof is an architectural device that is loved by designers for its ability to create simplistic linear forms. Adhesives may be useful in bonding the framing of the deck to the sub floor without creating holes. Two basic methods are used for framing a house.

Standard stick framing or the newer truss framing. The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle. Framing a roof is the last step in framing new construction. While most home builders will outsource the construction of roofing trusses the rafter supports of the roof itself learning to frame a roof yourself is one of the true arts of carpentry and a basic primer is covered below.

Some roofs actually slope in several directions ensuring optimal water runoff. This will help you create a flat roof framing plan. Nearly all roofs are framed using one of two methods. Which should be considered when investigating fixing methods.

With platform frame construction shown below walls sit on top of subflooring. Depending on the span many different materials can frame a flat roof. Flat roof framing is relatively straightforward. Just enough slope to drain water but also flat enough to be a problem if not constructed properly.

The rise or height of the roof at its peak is the altitude of the triangle. It can be framed like a floor system with horizontal framing members at 16 19 or 24 o c. Overhangs hips and dormers add greatly to the complexity of the framing. When framing a flat roof you will need to create a slight incline.

Put simply a warm flat roof has insulation of some kind packed into every available void and a cold flat roof allows air to circulate between the joists. 2x framing wood joists timber framing laminated beams steel concrete or sips. The run or half the building span is the base of the triangle. Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot.

Roof framing can be simple or complex depending on the roof. In terms of rules on ventilation bs 5250. This air is vented at either end of the roof to allow a continuous air flow. You can do this with a foam layer that exactly fits your roof.

Platform construction is much more common than balloon framing though balloon framing was employed in many two story houses before 1930.