View Full Version here: : Skillion roof or gable for roll off roof observatory
10-11-2008, 06:45 PM
I am looking at two different colourbond sheds at the moment a skillion roof and a gable roof. what are the advantages and disadvantages of both?:help:
10-11-2008, 07:49 PM
If you want to close the roof with any scope orientation, then with a skillion roof (I had to google that, means flat ;-) will need high sides and possibly restrict viewing near the horison. A gabled roof allows lower sides, but still quite high ends. I found a gabled roof needs some tricky internal bracing high up to avoid the scope on closing, to stop sag.
It all depends on the OBs size (the bigger it is, the futher away the sides are), how low you want to image, and wether you can park the scope flat before closeing.
Listen to Fred. He's been there and done that. He'll even tell you how to automate it through his patent advanced roof movement technology.:D
Go on Hough, do a Clark Gable.....you know you want to...........:whistle:
10-11-2008, 08:02 PM
You takin the piss, punk :whistle: :)
Motorised closing is easy, wind up a rope with a geared motor, the solution to megadata :D.
:lol: Nope, but I've seen your GRAS obs in action and was impressed how your got the synchronisation of the two shutters working. You sent me a link to a movie a while back. Was a little noisy (could have been echo due to operating it in a confined space for build/testing), but when you're operating it 1,200km away - who cares about noise right!:D
You still got the designs? Maybe worth sharing...
10-11-2008, 08:18 PM
umm, nope, thats embarissing, worked a treat untill it got windy, the one condition I couldnt test. The shutters were very efficient sails.
10-11-2008, 08:20 PM
I bet you a skillion dollars he doesn't...
Need a bit more info, Dave.
If your shed has a gable like 1ponders' then there's no difference when it comes to the height of the walls, etc. Paul's shed looks ideal to me. A gable is easier to build strong over a bigger span.
If you were building your own from scratch, then a skillion is far easier to DIY, and you could get quite reasonable spans and lightweight by using stuff like Paroc. But since you're looking at buying a shed and modifying, look for the one that has a complete roof frame as well as complete wall frames like 1ponders'.:thumbsup: It will make life much easier.
"Gone with the Wind", hah Fred?
Now you can groan Al ! :lol:
10-11-2008, 08:27 PM
Yeah, pretty much :mad2:. Still used with manual open close tho.
10-11-2008, 08:51 PM
I like gables, they just look better.
Weatherproofing is usually better on a gable roof because of the increased pitch.
Then there's the option of rolling part of the wall as well to lower the height.
Then again a man with your skills could conjure up a nice dome....:cool:
10-11-2008, 09:08 PM
Fred I have 2 pier tech type 2 piers (one for the eq6 and one for the G11) that I can raise and lower at a whim, so the parked position will be fully loaded ready to go. I can either keep the scopes low to avoid the breeze or the neighbours lights or raise them to get a horizon to the east and part of the north. i can see the SCP but have no real southern or western horizon. I thought the high side of the skillion roof can go towards the back fence and the low side to the eastern horizon? the size i was looking at was 3.8 by 2.3 from col western sheds, and getting a custom made welded door made for it?
10-11-2008, 09:12 PM
too dear for a dome - be cheaper to pay ponders to buy a shed in qld and transport and erect in wallsend NSW;):P:whistle:
10-11-2008, 09:17 PM
Thats a fair size, and with the adjustable piers (assuming you dont want to automate closing) a skillion roof would be much easier to build, Anyway, imaging close to the horison is often less than worth the trouble and time, and as you say, wind protection is a bonus.
10-11-2008, 09:19 PM
I was thinking more of a roll your own geodesic like Shawn built....
10-11-2008, 09:25 PM
the shed panels are prefabbed - and delivered to site - all i have to do is pour the pier bases and the slab (one pour, three sections all seperated by high density foam) erect the frame and then get a 2 c channel beams 8m long with two bracing beams in the middle and two steel poles. Much around and get some contraption made up for the roller assembly to fit on the outside into the c channel and some extra flashing to cover up the gaps and keep the weather out. sounds simple:whistle: no plans yet, but want to buy one as steel is going up in a weeks time apparently making the sheds about 200 dearer:shrug: the link to the shed prices is here http://www.colwesternsheds.com.au/files/colwesternsheds_sheds.pdf
10-11-2008, 09:28 PM
i am definitely not that smart or have that ability?
10-11-2008, 11:17 PM
I've been thinking about something similar - I am inclined to think the best roll off or slide off is a raised tie
is very flat which is good, and looks very rigid .
10-11-2008, 11:39 PM
Sorry, I don't mean to step on anyones toes....but all the talk about
roll off roof observatories ....one question....
Isn't a main factor for building one eliminating wind on the scope?
Or at least minimising it? Do Roll off roof obs suffer windage?
I really don't know....that's why I ask...
I know the shed with the roll off roof is a cheap entry point but
are people aware there is another cheap way in?
I made a foam dome in 2000.
Triangles of foam glued together in a geodesic pattern.
I copied a bloke's idea on the net...his name is Joe Garlitz.
Dozens of others have copied it...one being Baz from here on IIS.
It is CHEAP...and it's great fun...and it's portable enough to demolish and
/or take with you if you move.
Best thing I ever did in this hobby was make a dome.
Just thought I'd mention...there is an alternative :)
10-11-2008, 11:41 PM
How big will your slab be h0ughy ? and will you lay it yourself ? with reinforcing within ?
10-11-2008, 11:47 PM
I think domed observatories look great .... but , if you have more than one scope on separate GEMs and piers , you need a separate dome for each, and making the dome is very labor intensive and tricky for mug handymen like most of us are (including me).
Plus a dome in a backyard will make the building a villian magnet while a nondescript building with a normal looking roof looks like any old garden shed or small garage and probably not worth the bother for most thieves.
10-11-2008, 11:59 PM
All valid points Ian,
The dome I built was pretty easy to build, certainly not a lot more
involved than putting up a shed...It's not that fancy , trust me :)
In 8 years I have never had a villain problem...from the outside
doesn't look like a conventional dome...and it's not white.
It doesn't stand out at all in my garden setting.
I was just suggesting there is an alternative to a cheap housing.
11-11-2008, 07:15 AM
I had to look up the dictionary in order to know what a skillion roof is :D
I also had the idea of as single slope on the roof but then I turned it into a double slope and got the same height but the advantage was the slope in degrees per side was double as before :)
Here a side view of the Obs with the roof on top
11-11-2008, 08:02 AM
Can't see much detail in the brochure, Dave, but one photo in there suggests the sheds are panels only - no frame. Maybe it's just a shot from inside one of their little sheds:shrug:, but I think you'll need a reasonable frame in the walls and roof to support them without the roof being attached to the walls. As I said 1ponders shed looks ideal from that point of view.
If you get a panel shed without a frame built into it I suspect you'll have to do some framing...
11-11-2008, 04:47 PM
The 3.8m x 2.3m gable roof shed in Zn looks OK , room for the old kitchen table or the old timber office desk (both in the garage) to put the lappy on , the old Brown Build 7 foot tall two door stationary locker (has a deadlock on it from the garage) and for the old CG5 with a camera and guidescope on it and Altux with the 10" newt on it , on either their tripods or permanent concrete or steel piers) with room enough to move about without bumping into stuff.
Permanent polar alignment !!!!
Would free up the spare bedroom (scopes and mounts out of it) and generate some free space again in the garage .... sounds like a good investment.
Heading to Cardiff to look these things over - they have a "display" of assembled sheds.
Can't be all that expensive to mod it to make the roof roll offable (a couple of timber beams supported by some square steel fence posts + a couple of big plastic coasters on each side) and footings for the roof rails and a few odds and sods to make it all secure . Hopefully the roof is assembled as module and just lifted on and secured - the roofs look pretty light from the picture in the price list. (That's what I hope.)
Called the gang in Cardiff today (who said it costs $180 to erect these sheds and it is fiddlely and time consuming !!! .... that's probably money well spent ....) and asked for a quote on the slab (got a slightly sloping backyard) .
They told me to get a proper work shed the same size , I'd have to add $1000 to the price. I am not sure I want to spend near $2000 on a shed that will have to modded to make the roof roll on and off at this stage + the slab.
These panel sheds look good as futureproofing too , if the piers are bolted to the slab, and the shed is a modular construction (walls and roof can be taken down intact as modules) and it is bolted to the slab and can be relatively easily taken down if needed as a flatpack , then if we ever move we can take it with us.
13-11-2008, 11:04 PM
ok have changed my mind. i will be ordering a oldfields treco 3x4 with a single hinged welded door with a security lock. will cost for the shed 1270.00, then another couple of hundred for the timber framing and ply lining with some r3 batts between the walls and the ply, do the same to the roof. rolling assembly similar to basenuts with a ponders flavour v grove.
i am still tossing up the flooring, but will need to pour two mass concrete pier bases, with a little bit of reo and bolt mounting points for the piertech like piers i have. eiither concrete or timber hardwood for the rest
13-11-2008, 11:30 PM
Know what ya mean , decisions decisions !!!:shrug:
One option I am thinking about is using factory formed convex Zincalum roofing in my shed's roof .... this is better than a sprung convex roof I , I need to check that with the supplier (as it will naturally be convex curved , makes the construction of a rigid and strong roof much simpler I expect).
ie see attachments .
Anyone had any experience with this type of roofing ?
18-11-2008, 07:01 PM
Skillion roof is very convenient if you have it split in the middle as I do. The two sides of the roof simply overlay at the centre to seal the roof. Also when the roof is open they are very low as compared to a gable roof. I bought a gable roof shed to start with and then built my own skillion with white colourbond steel sheets from Stratco. You can see a few pics on my google website in my signature Dave.
My obs is currently in six sections waiting to move to my new location in 10 days.
18-11-2008, 07:19 PM
Toung and groove elevated flooring is all you need (isolated from the pier), all concrete floor is over the top. V groove rail will need accurate roof alignment, or it will jamb or ride up the groove and cause havoc. I used side alignment wheels, self aligning, no precision required.
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