Moving Roof Purlins

How to install purlins.

Moving roof purlins. Install the second row of purlins just like the first cutting the end piece to fit. Move two feet down the roof and snap a horizontal chalk line. What s the point of moving the purlin anyway just clean it up and expose it or board it. This one has held the roof straight for 60 years so no need to change i think.

Internal roof elements to consider during loft conversions consist of a number of sub structures such as ridge boards rafters purlins joists wall plates and steel beams. Install the second row of purlins just like the first cutting the end piece to fit. My question is how do i prop up the rafters so i can take down the existing purlin to insert the new rafters before building a timber structural wall further down to support the rafters the roof. Hi i am thinking of having my loft converted i need to move the purlins down to do this i need to install new 6x2 rafters next to the 4x2 rafters.

I will be putting in 9x3 floor joists. The term plate means a major horizontal supporting timber. A purlin plate in wood construction is also called an arcade plate in european english under purlin and principal purlin. By supporting the rafters they allow longer spans than the rafters alone.

The exisiting purlin is 10 2 i will replace like for like. The rule of thumb is to locate these cross braces one third of the distance below the ridge. Purlin plates are beams which support the mid span of rafters and are supported by posts. In the roof space as the name suggests the ridge board is the length of timber which runs horizontally along the apex of the roof.

When positioned roof purlins should be spaced no further than 1 2 metres apart when using sheeting with a thickness of 0 7mm and 1 metre when using 0 5mm sheeting. These help prevent separation at the ridge as a tension brace and also help prevent rafter sag from roof loading as a compression brace. In order for the sheets to be easily fixed to the purlins as a rough guide they should be at least 50mm wide. Purlin plates in wooden construction.

Snap the third chalk line two more feet down and continue down the roof until it is covered with purlins. Any expert views much appreciated. Move two feet down the roof and snap a horizontal chalk line.