Wood Flat Roof Framing Details

This is known as prescriptive framing.

Wood flat roof framing details.

The robust combination of structural characteristics results in a versatile economical framing member that is easy to install in residential and light commercial projects. Conventional light frame wood structures may be built without the need for engineering analysis of each component. Of course you don t need to live in a modern house to deal with a flat roof. The provisions for prescriptive roof construction are found in chapter 8 of the irc and in section 2308 of the ibc.

Having a manual for warm flat roof construction with details and a summary of rules to follow helps. Common types of roofs and basic framing terms. Gable a gable roof has a ridge at the center and slopes in two directions. The run or half the building span is the base of the triangle.

Within limitations which include among others building size roof. And the line length measurement from the roof peak to the building wall is the hypotenuse. The flange material is typically laminated veneer lumber lvl or solid sawn lumber and the web is made with plywood or osb. An example of each is shown in figure 2 1.

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. Chapter 7 ceiling and roof framing 40 ceiling joists 40 flush ceiling framing 42 post and beam framing 42 roof slopes 44 flat roofs 45 pitched roofs 45 valleys 48 dormers 48 overhangs 48 ridge beam roof details 49 lightweight wood roof trusses 49 chapter 8 wall sheathing 53 types of sheathing 53 corner bracing 54. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle.

The rise or height of the roof at its peak is the altitude of the triangle. Details for conventional wood frame construction 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. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof. Types of roofs the most commonly used types of pitched roof construction are the gable the hip the intersecting and the shed or lean to.

From there the flat roof system you choose will determine the materials you apply.