A little more progress yesterday evening…
I’d measured up for the north-east gable once, but when I came to check the measurements over they clearly couldn’t be right. The pitch of the roof wasn’t anywhere near the same as the southern end and that worked out fine. So I measured everything once again, this time clamping bits of scrap timber into place to give me marks to work from. My second set of measurements came out to within a couple of millimetres of those for the south-west gable, which pleased me greatly given how such a large roof frame was welded together sitting on saw-horses on my drive.
Happy with the measurements I cut the final sections of OSB to close off the gable and they’re now sitting inside the observatory waiting to be fitted this weekend. They’d best be right, as all I have left of the 20sqm of OSB that I bought or had sitting around to use on the roof is in small pieces that probably wouldn’t even cover 1sqm.
I’ve decided to try to avoid climbing onto the warm room roof to do most of the fitting. I reckon if I open the roof about 1/3rd of the way then I can hold the OSB in position and fix most of it from a ladder propped against the end wall of the warm room. If I struggle to reach the ridge then I’ll push it closed and just do the last few screws from the warm room roof. Saturday isn’t looking too clever at the moment weather-wise (again) unless I can get up and out there at the crack of dawn, which really isn’t me. On the plus side, the rain all appears to be coming in on southerly winds, so if I can’t get the membrane on until Sunday the OSB should still stay dry.