Step 1: Planning
My idea was to raised half the roof by constructing two new trusses and installing them on top of the exisiting roof joists halfway along the length and at the western end of the shed and to add another window to the southern wall. The elevated pitch on the trusses would give me a north facing clerestory window and an eastern window. The northern clerestory is primarily for summer, when I can open the south facing windows and the northern clerestory windows and the cool afternoon southerlies will blow and hot air will exit via the clerestory... well that's the plan at least, we'll have to wait for summer to test it. The eastern window brings in the morning light... that's a mental health thing for me, I love being awoken by the sunrise. Here's some of the sketches:
Step 2: Building
Well, I thought it would take two of us 1 day to build the trusses and 1 day to install... ummm. In reality it took us nearly a week to install; between bad weather, dumpster diving for materials, running out of roofing screws, patching holes in the corrugated iron, fixing leaks...
Firstly we built the trusses at my old workshop. This was pretty easy and we managed to build them out of dumpstered timber and mostly recycled screws. Then we had to move the trusses to the new place about 1km away. That's when we built... the trussbarrow!
At the new place, we removed half the old roof, installed the new trusses, built the three clerestory windows (also out of dumpstered wood and perspex) and covered the eastern window with offcuts of laserlite. We started out insulating the corrugated surfaces with store bought product that is a closed-cell foam precut in the same curve as the corrugations, but this stuff is expensive! In the end we made our own with old blue foam camping mats – it's the same stuff but waaaay cheaper and you can mark it by pressing an offcut of corrugated iron onto the foam and then cutting it with scissors.
I also put in two new rafters for the roof – I couldn't find any structural timber in the skips and I was in a hurry, so I bought 2 new lengths of pine... apart from the roofing screws this was definitely the most expensive part of the project. With the rafters installed, it was time to reinstall the corrugated iron for the roof, the old stuff fit on with just a little less overhang on the gutter side than the previous install.
Step 3: Evaluation
Well, there's some good news and some bad news. Let's start with the good:
The morning light hits the ceiling and spreads a beautiful golden glow over all that corrugated iron, like some heavenly spaceship! If you ask me, it's a very happy sight to wake up to. The shed feels a little like a camping hut and it's every bit as nice as waking up in the tent (as cold as that too!). The Eastern 'skylight' is definitely a winner. Also, all the extra bother pulling up the roof in other places and 'trimming' excess wall was worth the extra effort, as all the leaks over the electrics are gone.
And the bad news:
When I built the trusses I decided not to worry about factoring the existing roof pitch into their design (allowing me to build the trusses with a 90degree angle), and therefore knowingly installed the clerestory with a slight lean inwards. The problem with that is... rain! Yep, water travels down the window, hits the sill and runs down the slanting sill and inside the shed! Doh! Seriously though, you live and learn huh? I'll post the fix when I construct it, I have a few ways in mind but of course on sunny days I seem to forget the job and then remember again when it's raining cats and dogs.
The notion of funneling hot summer air out through the clerestory remains to be seen, I guess I'll post about that come summer.
