Flat Roof Joist Construction Details

What is the process of building a flat roof.

Flat roof joist construction details.

Using timber wall plates. Old asbestos roofs are often replaced with flat roofs. Sizes of joists needed for flat roof construction. This demo version is fixed at 1m clear span.

Good installation begins with specification of the correct joist for the application. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. In addition to floor and roof framing details this guide includes recommendations for cantilevers and placement of web holes. The construction of the flat roof is similar to that of the timber upper floor.

Important note for cold roof construction a 50mm airspace is required for ventilation purposes over the insulation the minimum depth of joist required is usually taken as 175mm even if a lesser depth would be acceptable from a purely structural point of view ventilation details for flat roofs. Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape. So any timber joists that are used need to be strong enough to support this weight. 1 enter joist details 1 1 span and joist spacing.

This article covers all manner of flat roofing venting methods and details on how to build a flat garage roof and how to frame a flat roof and also encompasses flat roofs roof decking roof coverings including flat roof felt how to prevent leaks at abutments timber flat roof construction details and parapets and common. There are key differences between constructing a flat roof compared to a pitched roof and it s important to understand the basic criteria. The full version allows any size. I joist construction details.

The major difference between the warm flat roof and the cold flat roof has to do with the air flow between the roofing timbers known as joists that help to hold up the roof. The starting point involves laying roofing joists across the two upright items which in most cases will be the walls of the structure. In the warm flat roof construction there is insulation packed into every possible space where air can flow. Of course you don t need to live in a modern house to deal with a flat roof.

By way of metal flat roof joist hangers. I joists in floor and roof applications. Masonry cavity wall flat roof insulation above and between joists. As you may imagine there is a fair amount of weight involved here in terms of boards felt etc.

Flat roof joist calculator. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.