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Anyone got a nesting observatory roof design?


Helen
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We've got a problem with the Obs ;) which may mean a rebuild. If we do rebuild we're looking at doing a couple of things differently -mainly the roof.

We're considering having a partly fixed roof (over the warm room) with the Obs section roof rolling over the fixed part. This has two advantages: its less weight to roll (important when you're only little like me ;)), and it will mean I can have an extra couple of foot of obs space without needing longer runners ;).

The concern though is getting roof completely rigid and stable.

I think a few people on here have similar set-ups, How did you do it please? And have you got any tips?

Many thanks :eek:

Helen

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Hi Helen

My current obs is full roll off but my 1st obs in the 80s :eek: yes I am that old, had a 1/2 roll off roof which pulled back over the fixed section of the roof.

It was a cunning plan ;) actually because I used a removeable apex runner. The roll off section ran on this and the 2 wall tops. Then when it was fully withdrawn you just lifted out the centre runner and you had an unobstructed sky. The front walls were hinged at 1/2 height so these could be lowerd and the 1/2 side walls did the same.

Unfortunately I dont have any photos but I could do a sketch and scan it if your interested.

Philj

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I orignally had a roll off roof but as it took up too much garden space I was able to cut the roof in half at the apex, placing two planks sideways overhanging both ends of the shed I was able to move the roof out sideways. Doing this helped in a number of ways, less weight to move, no uprights required and best of all only open enough as was necessary. Weatherproofing was not a problem, castelating and greasing a number of lengths of wood at the apex ensured no ingress of moisture in the centre.

Jim

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It was a concept I was considering for my obs, but trying to get an apex roof to roll over another apex roof and still be strong enough so it doesn't collapse because all the traditional bracing has been removed is difficult. If you make the roll off section with the traditional triangular roof supports, then the warm room will need a flat roof. This then gives you the problem of rain run off - so you make it pent, which then reduces head height. If you increase the headroom in the warm room it means increasing the wall height, so then you look at removable panels... but this can then reduce the structure strength.... Like Gina, my head is spinning trying to come up with a decent design that works

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My old obs had 1 triangular brace at the front of the roll off apex roof.

This maintained the structural integrity of the roof at the front, the rear was supported by the warm room fixed roof.

Then when the roof was pulled back it would only go as far as the brace but that was positioned at the gable and the dimensions of the roof were such that when this was fully back a full half obs was exposed.

Philj

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Use internal bracing at the front end, as Philj describes. How about using external bracing at the back-end? Doesn't look as pretty, but would be very rigid and do the job nicely. Quick description for clarity - an upright rising from each of the 2 side runners at the corners of the "back end", then a cross-beam that joins the risers at the height of the apex. Attach the apex to the centre of the cross-beam. In this way the roof "hangs" from cross beam. Think of a suspension bridge, as opposed to a traditional arch bridge. I'm sure I've seen some designs like this on the web, so my idea is not original!

Kevin

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I had a similar problem so I (copied from various other obs.) simply allowed the whole roof to slide but the warm room is covered at all times. OK the warm room is nit air tight but should be good enough. Worked so far but I have yet to put it through a winter.

http://stargazerslounge.com/diy-observatories/139653-new-observatory-finished-almost.html

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A pictures worth a thousand words they say, not this one :eek: Just dug this out its in BW, lucky its not sepia its that old:) It shows the obs from the front with the sliding roof cross brace in place and the roof slid back.The front half walls are down but the side 1/2 walls are up for protection

It was built in my mates mums back garden, thats his 8.25" newt and my Tasco 10TE on homebrew mount.

Philj

post-14930-13387760567_thumb.jpg

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Ive just had a brian wave (rare I know !) - what if you had a 3rd rail - on the apex of the warm room. Then as the obs roof rolls over the warm room roof, rollers on the underside of the obs roof engage on a runner on the exterior of the warm room roof which intern supports the obs roof as it rolls over - hard to describe, will try and draft up a sketch

post-23388-133877605754_thumb.jpg

Edited by malc-c
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I think Martin has the best solution, if you dont mind a flat roof. I have also considered this when designing my theoretical obsy. It would be good to roll off the roof over the roof of the warm room. Other ideas I had, though, have left this design in its infancy and not developed.

Also, as Malc suggests, you could use a traditional roof design utilising a collar or raised tie (ROOF TRUSSES | ETS Trusses). Im actually at work now so have access to my favorite books for reference - they are Mitchell's Books called Structure and Fabric Part 1, Part 2 and Introduction to Building. The first books I ever brought when I started my training as an Architect....very useful....

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I went for the flat roof design because my obs is aligned east/west, so with the roof open I would have less obstruction on the west side. The lowest side of the sliding roof is only 2" above the fixed roof, + 2" of timber frame + 3/4" ply. The other end is all that + 6" for the fall.

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My obsy is pretty much the same as Martin_h's Helen, you are welcome to come visit if you like.

Things to bear in mind are run off, and a structure that will prevent twisting and flexing of the frame.

Tim

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Well as far as mine is concerned I have a good one, it has been built on restrictions and considerations, the material, space, security and what sky is available. I have also taken into consideration the impact on the garden, blending in where possible.

Jim

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Helen

Please find attached the plans that I came up with for my observatory (I've finally finished them). Like you I'm short of space so I came up with a nested roof solution, I also wanted an unresricted view to the east, south and west elevations so I decided to incorporate the upper part of the east & west walls in the roof and have a fold down flap to the south.

You may have to build this design as a DIY project as I have approached a few shed manufaturers and Alexander observatories and the said they couldn't do it. I will probably be starting my version of this later this summer. your quite welcome to use these plans or use them as a starting point for your own design.

Regards

Darren

Observatory.pdf

Edited by dazza1639
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Helen

Please find attached the plans that I came up with for my observatory (I've finally finished them).

Regards

Darren

Very professional plans there Darren and an innovative design - look forward to seeing how you get on when you start construction.

Kevin

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Helen

Please find attached the plans that I came up with for my observatory (I've finally finished them). Like you I'm short of space so I came up with a nested roof solution, I also wanted an unresricted view to the east, south and west elevations so I decided to incorporate the upper part of the east & west walls in the roof and have a fold down flap to the south.

I also have a gable flap that folds inwards on the east side of mine. To close to the boundry to open out....would have to go nxt door to close it ...LOL

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Very Impressive...Your base is about the same as mine, my original thinking was to build a dwarf wall and then hang joists for the floor, hence the 12-18" footings, but I noticed you laid a large slab. What was the approx number of barrow loads or cost for the base?

Also, does the timber yard you got the shiplap from deliver throughout the UK ? - finding it hard to locate a local company that does reasonably prices T&G in lengths of 4.8m

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It would be nice to have an observatory with walls at waist/chest height but as i am sourrounded by sodium lights I have kept the walls to a height where I am not disturbed by them. The other problem would be security, as I am enclosed less people will see what I am doing or what I have. :)

Jim

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