Hello,
I'm building a quirky shed myself. It's not finished yet but here are some photos. I chose not to go with wood for the walls for maximum stability but I have used a fair amount wood for the joists, window frames, porch corbels etc. Most of it is reclaimed, stuff I found in skips etc apart from the roof trusses which are new and pressure treated. I didn't want to take any chances with the wood failing and making a roof is much easier when the timbers are straight and not bowed.
I would say, where structure is important as in the roof, use pre-treated timber and use 'wood with character' to clad it. Obviously a professional carpenter might have different opinions but I'm only a software engineer by trade so chose to play it safe.
The attic floor and and joists are made from old scaffolding boards which are very tough but don't need to be 100% true and neat.
I looked at wooden roof shingles myself but I determined they were not easy to get hold of and quite expensive. If you have access to a lot of wood, cleaving your own could be an option. I've read on the web about some people having luck with wooden shingles made with old pallets. I was going to try that but then thought for my own shed it was too much hassle. Instead I went for cembrit jutland slate effect tiles which look ok, are quite cheap (about 90p) and very light so it doesn't tax my roof too much.
Other general advice:
-if you need planning permission, before you do anything go around to all of your neighbours with plans in person and tell them about your intentions. If they have any reservations, you can address them from the start and when that scary official looking letter comes from the council your neighbours won't be panicked. A friend in the family who is a town planer told me that and it certainly helped me. I didn't have a single objection.
-I also found building a detailed model in 3d very helpful in planning for materials. I used sketchup but there are others.
-Tell everyone all about your project you meet. You'll be surprised at the useful bits of information about building you can gather from people with experience.
-Scour ebay, gumtree and freecycle regularly for materials well in advance whilst in the planning stages. You can get some great bargains if you plan in advance and some quirky things will come up which will enhance your design. In gumtree and ebay you can set automatic searches which email you when things come in. Through that I got my decorative ridge tiles for £20 and the bricks for my chimney for £30. I also got 15 bags of sand for £15. The double glazed windows were fly tipped near me. I stripped the plastic frames off and made new ones with reclaimed oak.
-it's always worth blagging an account with trade only builders merchants for better deals. (Usually a made up letter head is enough to get a trade card.)
I hope that helps, if you've got more specific questions, fire away!
Gibbo84
