I used colorbond fencing materials to build my obs' its cheaper and can be modified as per height of walls and size by adding panels as req'd. Panels inc posts cost approx $120 per 2.4 x 1'8 meter---multiply x4 = $240 for 2.4x 2.4 obs' plus roof of your design. This is much stronger and will support more weight of roof than any garden shed I have seen. And as a bonus lining the inside with pine lining boards is easy as they fit the gaps between the posts and th sheeting material.
GoodayI.C.D, Here are some pics of my obs. I have heaps more from basic layout to finished and fitted out If you want to see more or ask questions ask.
I'd be worried about the strength of fencing sheets unless they are well rivetted together and rivetted to the posts and rails.
Too easy for villians to kick them out and get in if they think there is more than some gardening gear in there. I wouldn't insulate the walls either apart from from blue coated aluminous foil stuff to weather proof the walls..
Thanx for looking Ian
All sheet overlaps are riveted and the lining boards add strength and intrusion protection and of course fitted with burglar alarm.
By any chance have you tried to get through a colorbond fence? it is near impossible to remove a sheet without removing upper or lower rails first
Why wouldnt you insulate the walls if you dont mind me asking.
My son went though a colourbond fence playing with his mates in the yard once.
Wouldn't insulate it if it's going to be an observatory as you want the slab and scope to stay close to ambient temp, if it's warmer, will generate thermals and you'll see them as bad seeing through the eyepiece.
If you're going a pre-fab shed and modifying it, maybe you could get one with a gabled rood and consider the "roll-down" design too. I'm just about to lay a slab for one of these:
The sheets in a fence are just sitting between the two rails though - you only need to bend them enough to shorten by about 30mm and they pop out - riveting them in would make a nice solid wall.... looks good timelord!
Thanx for the comments guys here are some more pics and details. Walls are insulated with insulation foil and of course the lining boards, roof is insulated with foil and insulation batts.
Vertical load bearing is heaps better than the average garden shed--espescially once youve removed the roof. Pre painted --your choice of color I have rivetted the sheets to the upper and lower rails in strategic positions to improve intrusion integrity.
The roof rolls on 6 wheels in 6" purlins.
Only part of the roof slides open--due to the odd shape of the observatory and after much design consideration came up with a design of sealing a sliding roof to a stationary roof as it closes, works brilliantly and is as tight as a fishes a***e.
Any drawing or photo you have to help will be great the roof has been one area I need to seal as I have a idiot who has a dirt bike and likes to ride when the wind blows and the dust comes over my place (##***###)so I would like to have it dust proof .What is the floor made from timber or concrete
What a lot of fantastic, beautiful, brilliant, ingenious, neat examples of what can be done with a little bit of good old imagination and positive energy!
I take my hats off to you folks for the things you build!
Gooday I.C.D, As the purlins sit directly on the top rails of the colorbond rails, these two sides need no further sealing as they fit snugly.(maybe a thin bead of silicone sealer if req'd)
The front closing edge in my case fits and butts up against and under my deckings veranda guttering but you could easily employ a fascia panel if yours will be free standing. The rear closure employs a drop down panel from the roof which slides open with the roof and also seals to the top rail of the colorbond fence top rail.
A simple rubber strip completes the weather proofing here. Rubber sheeting cover the gap left by the pitch of the roof to the purlins which also slide with the the roof.
The flooring is made of timber (tongue and groove pine floor boards. The floor is completely isolated from the pier's concrete foundation. I still have some dust issues with the open ends of the purlins and will resolve these shortly when I come up with an idea!
I'll post some more photos relevant to these items tommorow If I can, hope this helps.
Al.
Here are some more photos as requested showing the roof drop down panel partially open, the rubber cover for the gap left by the roof pitch and the roof fully open and a close up of the latter.
The last one shows the roof over my decks veranda and the gutter that the obs roof slides under when fully closed.
Hope these help with your roof design.
Al.
I had fairly detailed drawings and plans, made myself - mainly to simplify building. I made sure that the spacing of wall studs meant minimal cuts to wall sheeting etc - and try and keep to standard widths for the same reason.
Saying that though, there are things that pop up that you won't have thought of, so slight deviations will likely be needed......
The best shed is the one you can modify without too much expense and that is big enough for your setup. Mine is 3x2.4m ... enough room for scope area and computer area. My biggest scope is 1.2m long so at 2.4m I can still get around the scope relatively easily although carefully in the dark when the roof is open. Click the link in my signature and have a look. Or check out my thread in this forum.
Gooday Ian, unfortunately no drawings, my design process consisted of sitting on a chair at the proposed sight with a beer and contemplating various design possibillities, having another beer, setting out string lines including line of sight from wall heights to viewable horizons, having another beer and so on .It took several of these sessions (and beers). I had several design problems with the fall of my land and the odd shape of my block. The final dimensions of the obs were 2.4 X 3.6 at the front and 3 meters at the rear.Council regs allow a garden shed without permit of 10 sq meters and I was just under it from memory.
The rolling roof is 2.4 X 2.4 the rest of the roof is stationary and as I said before the sliding roof seals water tight over the stationary part when closed. The floor is at the same height as my deck so there is no step up or down at the entrance.As mentioned previously floor is timber and standard decking style bearers and joists were employed, the lower rails of the fencing material were screwed to the top of the perimiter bearers. I guess the easiest method for you would be to look at a colorbond fence and envisage 4 panels arranged in a box shape with the uprights screwed to 4 posts 1 at each corner pretty simple , remember wall height is easily adjustable to your requirments by cutting the sheets to your desired height I used standard 1.8 meter lengths. 1 panel equals 2.4 meters long add more as req'd to suit you own design. Purlins for the roof sit directly on top of the upper fence rails an secured to the corner posts, purlins were standard 150mm X 5 meters and of course you require two extra posts to support them at the end to which the roof slides to open. Wheels were purchase through e bay for $3 each, also available at Bunnings for a bit more.
The cost of the basic enclosure was about $1000 inc posts and concrete not inc any timber(flooring and lining boards) Very competetive with a prefab shed of this size and a whole lot stronger plus its painted inside and out and color coordinated with your existing fence and adjustable to your needs size wise. Just add roof and your right to go.
Al.
Al,
I like the way you think a beer then do a bit ,and like you I have ground level problem I will send you a pic of my site Thanks for all the info, between the text and photo I should be able to put something together .
Well, I just used a 7ft x 5ft garden shed. Plonked it on the lawn and put 3 dobs of concrete for the tripod legs to sit on once polar aligned. Never had to align it again. The "sliding" part of the roof was simplicity itself - I just balanced the roof on top of the walls, and weighed it down with 8 bricks When I wanted to observe, just removed the 8 bricks and pulled the roof off towards me
The inevitable happened one day though....... A huge storm came through one afternoon, and the roof just flew off down the garden. BUT guess what??? The previous day, I had removed the scope into my garage for some reason I still can't fugure outAll the damage was bent roof, and soaked star charts I reassembled it with heavier bricks and included a rope over the roof tied down to large tent pegs
All the damage was bent roof, and 
soaked star charts
