What size timbers do I need for a flat roof?
The joists should be sized using either the TRADA span tables or BS EN 1995. The sizing and spacing will depend upon the loads imposed on them and the required span. Wherever possible, joists should span the shortest distance. Common joists sizes are 200 x 50mm, 175 x 50mm, and 150 x 50mm.
Can I use 4×2 for flat roof?
2×4 rafters are not strong enough for low pitched roofs under any circumstance, so avoid if you are building a shed with a flat or very shallow roof.
What supports a flat roof?
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.
What thickness ply to use on a flat roof?
18mm
A flat base is required to lay the roof covering on. This can be either Smartply OSB3 or good quality, structurally sound WBP plywood. A minimum thickness of 18mm must always be used.
What is a C24 joist?
C24 timber has been graded to a higher standard than C16. It’s a premium piece of timber that can handle higher loads and wider spans. C24 grade can only be achieved by importing timber from areas where the climate forces a slower growth rate and hence a tighter grain.
How far can a 2×6 span on a flat roof?
What is this? A 2×6 rafter can span 14 feet 8 inches when spaced 16 inches apart with No. 1-grade southern pine lumber on a roof with a 3/12 slope or less with a maximum live load of 20 pounds per square foot and a dead load of 15 psf.
Which plywood is best for roofing?
Exterior Plywood is the preferred material for roofing. It also performs well when exposed to moisture over long periods of time. The price is low compared to other roofing materials and the installations are also easy.
What type of wood is used for roof trusses?
Answer: Yes, species combinations like Hem-Fir and Spruce-Pine-Fir are used regularly in truss manufacturing as well as Southern Yellow Pine and, as you mention, Doug Fir-Larch.
What kind of wood is used for flat roofs?
In the majority of cases the covering will be plywood or OSB timber which is more commonly called Stirling board. When timbers are used in flat roofing they obviously need to be waterproofed so boards are normally laid across the joists and then a felt or rubber is used to cover the boards to make them waterproof.
What is the best material to use for flat roofs?
For many projects, PVC roofing is our preferred choice as the best flat roof material on the market. PVC roofing is somewhat more expensive than other single-ply commercial roofing materials, however it offers a wide range of benefits for the price.
What is the best board for a flat roof?
Only OSB/3 or OSB/4 (BS EN 300) should be used in flat roofs. Check that the product has a certificate from the British Board of Agrément (BBA) before agreeing to its use. Thickness: minimum 18mm is recommended.
Is C24 a pine?
Manufactured from high quality Scandinavian unsorted grade redwood (pine).
What is timber flat roof construction?
Timber flat roof construction usually consists of structural joists topped with a decking of plywood or a similar sheet material. Wherever possible, joists should span the shortest distance of the roof plan .
What kind of wood is used for a flat roof?
In the majority of cases the covering will be plywood or OSB timber which is more commonly called Stirling board. When timbers are used in flat roofing they obviously need to be waterproofed so boards are normally laid across the joists and then a felt or rubber is used to cover the boards to make them waterproof.
How do you build a warm flat roof?
Having a manual for warm flat roof construction with details and a summary of rules to follow helps. The basic construction of a flat roof starts with roofing timber that is laid across two upright items, usually two walls. For additional stability, you can also use steel joists that are built into one or both of the walls.
Why choose aboutabout roofing supplies for flat roofing?
About Roofing Supplies offers the highest quality Sheet Timber For Flat Roofing which can be used for roofing or flooring applications. Our Sheet Timber is extremely durable and with edges machined for a perfect fit you are sure to be completely satisfied with this product.