I started by building a ridge for the tops of the rafters to sit on. This is a slightly unconventional technique - normally a ridge beam is held up by 'cripples' which support the rafters while they are built; the cripples are then removed, and the rafters support the ridge beam without any assistance.
I decided to do things slightly differently - having a permanent and supported ridge beam seemed like a better structural solution to my (untrained) eye, it would allow the incorporation of oak braces in the roof which would provide some lateral stability, and the braces would look pretty from inside as well!
This was the first section of ridge beam and braces in place. The ridge itself is structurally graded softwood - this provided Roy, our Structural Engineer, with a known quantity for his calculations. Oak is less homogeneous than graded softwood, and therefore easier to calculate (even though it's probably weaker!) The uprights and braces are oak, as they will be visible from inside.
The rest of the ridge raced up, and then it was time for the rafters. The longer lengths had three birdsmouths - at the ridge, the main wallplate and the catslide wallplate. I read a lot of theory about calculating rafter cuts, but I wasn't confident in my abilities to get the cuts accurate.
Sadly I didn't photograph my solution, as I'm quite pleased with it's simplicity and effectiveness! In short, I cut a spare rafter into a template, leaving 2/3 of the original depth for a foot either side of the birdsmouth. I then cut a scrap piece of plywood with a 90 degree notch. I placed the template rafter in position at 600mm centres, and then screwed the plywood onto the rafter template, ensuring it was tight to the wallplate. The template rafter was then removed, and I could trace the position of the bridsmouth onto the real rafter before making the cut.
The result was really good - surprisingly so. All the birdsmouth cuts are tight and accurate - a really pleasing outcome which was very satisfying.
Batten was next - this raced up with help from my father Martyn. All were screwed in place - I have a complete aversion to nails...
The cedar shingles arrived soon afterwards - the best part of a tonne I'd imagine, as the tractor couldn't lift the pallets until they were about 1/3 unloaded. We used the second-best grade of shingles - Number 2 Red Label shingles. We had about 5,500 delivered.
Each needed two fixings per shingle, in stainless steel to prevent corrosion (cedar has a high tannin content, which is corrosive to ferrous metals). I decided to use 28mm stainless staples, fired from a pneumatic staple gun, which saved a huge amount of time over nailing. I could reach the first eight or ten rows from my Youngman boards and ladders, before it was time to hire some more kit.
The job itself was fairly hateful, due mostly to the weather. We had gusty wind for most of the week that I was doing the roof, and loads of the shingles blew off the platform I rigged on the cherry picker. It rained a fair amount as well, making the roof slippery to work on and caused the cherry picker to start sinking into the soft grass.
A regular motto of mine is 'Time Spent Making a Jig is Rarely Wasted'. This is the shingle fixing jig I made - the top hooks onto a row of batten, allowing shingles to be hung on the lower edge - all in a straight line and at the correct height. There are also two string lines across the jig which show where the staples will penetrate the shingle and hit the batten below.
I finished the shingles after a 14 hour shift, trying to meet the hire deadline. We had the inevitable 'topping out' ceremony with a bottle of beer to celebrate the end of a physically demanding part of the build.
The shingles do look fabulous - they really change colour as they weather - they are quite a light grey now, but shift to a really deep orange and red when they are wet. You can also see the two Velux windows and chimney flashing in this picture.