Their strength means they can span greater distances than other systems and often eliminate the need for beams and purlins.
Posi joist flat roof.
The following easi joist.
Flat roof joist calculator.
Boarding to be fastened on top of flat roof joists with a depth to width ratio greater than 4 the allowable clear spans have been calculated in accordance with bs 5268 2 2002 structural use of timber part 2.
The full version allows any size.
To build a roof joist for a flat roof you need some carpentry skills and a few basic tools.
The strength of the posi joist floor provides greater room widths for increased living space within the attic delivering maximum value to the client.
This demo version is fixed at 1m clear span.
Posi joist can adequately span for floors and for flat and pitched roofs often allowing for increased joist centres when compared to alternative systems.
How to install joists for a flat roof the roofing surface is installed over the joists while insulation is placed between them and the ceiling beneath is suspended from them.
Posi joist also known as metal web joists combine the light weight of timber with the strength of a steel web.
1 enter joist details 1 1 span and joist spacing.
Top hung joists can be supported from trimmers with no need for a hanger.
These chords are plated together with a precision engineered and manufactured structural component called metal web these when combined form the easi joists.
This is the distance between joist centres.
This extension to a veterinary practice in north cheam in surrey required a flat roof approximately 130 metres square.
Flat apartment floor.
In roof applications posi joists are incredibly versatile and can be used for flat low and steep pitched roofs.
Maximum clear span of flat roof joists in metres for sc3 timber spacing between joists size of roof joist 400mm 450mm 600mm 47 x 97 1 84 1 81 1 74 47 x 120 2 43 2 39 2 27 47 x 145 3 08 3 02 2 87 47 x 170 3 75 3 67 3 42 47 x 195 4 41 4 31 3 92 47 x 220 5 04 4 85 4 41 75 x 170 4 50 4 38 3 99.
Posi attic trusses combines the solid feel of a posi joist with the benefits of a conventional attic truss.
The posi joist gives building designers the freedom to have a variety of internal room layouts without the constraints of solid and other engineered timber.
Code of practice for permissible stress design materials and workmanship and bs 5268 7 2 1989 structural use of timber section 7 2.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
