The SE has specified the timber sizes and fixings but not the grade of steel (mild or high tensile?), or the finish (bzp, galvanised or stainless?). It is to strengthen the main roof on a victorian terrace where the replacement concrete tiles have increased the load over the original slate tiles.
Is there a minimum standard to use?
Blup
The timbers are a pair of opposing 6x3 struts sitting on a central wall, and are connected at purlin level by a pair of collars (8x2). So about 175mm of timber to bolt through and together.
Is there a minimum standard to use?
Blup