What size roof timbers do I need?
Roof pitch between 30 and 45 degrees with rafter spacing strength class C16
| Size of rafters in mm | 400mm | 600mm |
|---|---|---|
| 100 x 47 | 1.91 | 1.78 |
| 125 x 47 | 2.52 | 2.33 |
| 150 x 47 | 3.14 | 2.88 |
What size wood do you use for rafters?
You can use either 2×6 or 2×4 rafters for roofs with a 3/12 pitch or greater, but it depends on the overall size of your shed. For roofs that won’t experience heavy snow loads, a gable roof can span up to 22′ with 2×4 rafters.
What size rafters do I need?
As per general rules and guideline, for 10 -12 foot span, generally you need 2″×6″ size of rafter, for 15 -16 foot span, you need 2″×8″ rafter, for 18 – 20 foot span, you need 2″×10″ rafter & for 24 foot span, you need 2″×6″ size of rafter placed at 16″ apart from centre.
What size timber do I need to span 3m?
For example, a clear span of 3 metres will actually require a timber member in the order of 3.3 metres long. This will have 100-150mm of timber at each end, resting on some form of support: and this may be a wall made of brick or block, or maybe a timber stud frame – or it could be a joist hanger.
Can I use 2×4 for roof rafters?
A 2×4 can span a maximum of 6′ 7” when spaced 16” apart and used as a floor or deck joist. When used as a ceiling joist or a roof rafter, a 2×4 can span up to 7′ 3” spaced at 16”, and 6′ 4” when spaced 24” apart.
What size should pergola rafters be?
4″ x 2″
Geoff, a builder friend, once said that for a smaller sized pergola, with 4″ x 2″ rafters, the pergola beam span should be no bigger than the width of a standard fence panel, or 6ft. Good advice! Try to keep as near to that as possible.
What is gable width?
When designing a gable-end eave without a return, the dimensions to look at are the width of the trim (set between 6 in. and 8 in. thick) and the overhang from the side wall (set between 12 in. to 18 in., depending on the style of the building). avoid gable ends that are over 8 in.
How much weight can a 2×4 rafter hold?
A 2×4 can support up to 1,000 pounds vertically. This dimensional lumber is the most common material used to frame interior and exterior walls on a home. When used as wall studs, 2x4s are typically grouped to create a wall, spaced 16 inches apart.
How much space do I need for a pergola?
So for this particular pergola we’d need to position posts at 5′ in from the outside posts, giving the two 5′ spaces and a 10′ space in the middle. Increase the timber to 2″ x 8″ and you’d probably get away with having a 4′ end space, leaving a 12′ centre measurement. Do be aware however, that this wood will be extremely heavy!
What is the best material for a pergola?
Pergolas can be made from a variety of materials, but wood is the most common. Softwood is the cheapest, and provided you buy pressure-treated timber and look after it, it will last well. For the uprights you will need at least 75mm x 75mm (3” x 3”) timber, and 100mm x 100mm (4” x 4”) is better if it is to be a sizeable structure.
Can you shorten the span of a pergola?
This option not only provides interest to the structure, but also keeps the centre space clear (which is the main concern usually). Here we have a very long pergola beam span of 20m. To shorten the span, install two additional posts to bring the centre distance to around a maximum of 10′ (less if possible).
How long is a pergola beam span?
An 18′ pergola beam span is long. If you’re erring on the side of caution – or even if you’re not – it’s too long. This hexagonal pergola is large, so needs to be very secure.