Strapping in New Rafters

 Now that the steelwork had been installed, I was finally free to begin the extra roof-work that would be needed to support the outer room plasterboard roof. This involved adding a whole new layer of rafter collars below the recently added Flitch Beam, to which I would then attach the plasterboard. 

Here is a reminder of the plan - the upper rafter collars are marked in black, and the lower collars that I am talking about here are marked in red. The yellow line then represents the connection between the two: a 2by4 timber noggin reinforced with a steel restraint strap.

To achieve this, I used the original pieces of 2by6 that I had taken down earlier in the project to facilitate the removal of the old purlin. I attached these using M12 high tensile steel bolts, nylon threaded washers (to stop them coming loose), and 50mm steel square plates. Here is a picture of me installing one such rafter collar:

I found the best way to do this by myself was to use a loop of string around one end of the rafter that I hung from the roof. I could then hook one end in to the loop while on the ground, before climbing up the ladder with the other end of the wood and using a clamp to hold it in place. Once this end was clamped, I would then climb down, move to the other end and clamp this up too. Then I would drill the hole (using a self drilling flat wood drill bit), and knock the bolt in place with a hammer before tightening the nut with an M12 attachment on my impact driver, while holding the other end with my torque wrench. 

This is what it looked like after several of the rafter collars had been installed:

Next, I cut and installed some vertical 2by4 noggins between the upper and lower rafter collars to add rigidity, as you can see below:

Finally, I reinforced this connection with steel restraint straps. For this I used light duty "L" straps, but I cut them to length with an angle grinder, and bent the top section over to create a hook shape so that I could have more surface to screw them into the top rafter collars. 

Here's me screwing the straps in - you can see how I'm screwing in the top of the "L" strap that I have bent over, so it's on the back of where the strap is:

And here's the finished product:

Next up - Additional Roofwork