Gina's Observatory

[Gina]

I did it with wooden slats for channels with the wheels on the wooden structure. I would not advise doing this as the weight of the roof going over the wood is causing the wood to split, then the rain gets in and it gets worse. The wooden slats rub against the side of the wheel but i fixed this by putting a couple of small guiding wheels on the roof to make sure the wheels stay marginally away from the slats.

I am now doing what i should have done in the first place which is putting down angle iron but keeping the guide wheels on the side to, again, ensure the wheels dont rub.

Ah, I see. I have some angle iron lengths but they're only 2m long so I'd need joins. But rubber tyres would be OK going across joins if they were carefully butted up I think. OTOH I have only 4 pieces so wouldn't have enough for both rails.

The wheels are 75mm diameter nylon?? With a load capacity, i think, of 50kg each.

So i would say put something down for the wheels to run on.

Yes, I think hard nylon wheels would not be good on wood which is one reason I got some rubber tyred wheels. I still have the eight 80mm nylon wheels I got originally. I could use those in aluminium channel.

[Gina]

Been costing some of the options for guiding the roll off. Don't currently know the shipping cost of the gate track and wheels but I estimate the total cost as between £60 and £70. Aluminium channel works out at £38.73 from Aluminium Warehouse (the cheapest I've found so far).

Today I made up the rubber tyred wheels with supporting wood sides and SS bolts and that rolls very freely along the 75mm wide timber running track. Even when I hung on it, it would still move easily. I was successful at getting the holes well aligned and all the wheels seemed to be taking the weight. Just needs something to make sure the final complete trolley/ROR keeps straight. If I can find some rollers or casters, that would be a cheaper and quite effective method. Something like cotton reels on bolts would do. Or maybe even PTFE blocks perhaps. I can't find any suitable casters on the web so far. There are some from Hong Kong on eBay but the delivery time is 12-24 business days. Some lateral thinking may be indicated

[Bizibilder]

How about ball bearings with a bolt through the middle - if the bolt is a bit undersize you can adjust things to a nicety. You can get bearings quite cheap from: Arc Euro Trade - Bearings or look for a local supplier (agri -shop may sell them?)

[Gina]

How about ball bearings with a bolt through the middle - if the bolt is a bit undersize you can adjust things to a nicety. You can get bearings quite cheap from: Arc Euro Trade - Bearings or look for a local supplier (agri -shop may sell them?)

Yes, I did think of that but thought ordinary steel bearings would rust. I know you can get sealed bearings and I guess a bit of rust on the outside doesn't matter too much. Or I suppose you could paint them. OTOH maybe go for stainless steel (if you can get them). Small sizes shouldn't be too expensive.

Just had another thought - skateboard bearings, very cheap and should be reasonably water resistant I would think. Worth a punt I reckon.

[Gina]

I've decided to order a set of skateboard bearings and use the rubber tyred wheels on wood. If the wood shows any sign of deterioration I can add some flat ali strips later.

[Merlin66]

Gina,

My roof is 6' x 8' and just runs (well!) on 6 x 75mm nylon wheels straight onto a 2" x 2" support. An edge strip of 6mm marine play gives "guidance"

Now well into it's third year and no issues......

[Gina]

Gina,

My roof is 6' x 8' and just runs (well!) on 6 x 75mm nylon wheels straight onto a 2" x 2" support. An edge strip of 6mm marine play gives "guidance"

Now well into it's third year and no issues......

Thank you for that Merlin Very interesting. My roof is 8' square and the roll-off unit includes a 2' 6" wall on one side and a foot wall on the other. Plus gable ends. I'm running on 5 100mm rubber tyred wheels on the heavier side and 4 of the same wheels on the lighter side. I think the roof unit will be quite heavy, though lighter than my original design.

I think, on second thoughts, I might see how the roof runs with very simple guides before I buy bearings. As it is (testing the wheel units) there seems to be no tendency to roll off-course. So I might just try some simple stops to prevent it coming off. It'll probably want "hooks" to prevent it lifting off in a gale anyway.

[Bizibilder]

For gale proofing I made some steel "bolts and holes" that the roof closes onto. One bolt locks everything at the end of a session and there is no way it will blow away! (Have a look at my blog in my sig - goto 2010 June for some pics). Dead simple to make (you don't really need a lathe!).

[Aoraki]

Bizibilder.... that's the solution I was looking for, cheers mate! I will be using a sprung latch though instead of the tower bolt you have used. Like this one.

[Gina]

For gale proofing I made some steel "bolts and holes" that the roof closes onto. One bolt locks everything at the end of a session and there is no way it will blow away! (Have a look at my blog in my sig - goto 2010 June for some pics). Dead simple to make (you don't really need a lathe!).

Yes, I remember that. Good system I'm hoping to do something similar with a sprung bolt or other fastener to lock it in place.

[yesyes]

Make sure not to put one of these in each corner... You'd need 4 people to open the roof.. ;-)

[pritc]

I do not know if you remember my tie down solution for my build, Gina?

3/8in Turnbuckle and hook plates all from 'Screwfix

Wayne

[Gina]

I do not know if you remember my tie down solution for my build, Gina?

3/8in Turnbuckle and hook plates all from 'Screwfix

Wayne

Yes, I remember that Wayne Isn't it a bit fiddly for everyday use?

[pritc]

Yes, I remember that Wayne Isn't it a bit fiddly for everyday use?

Not really, 3 or 4 turns and each one is undone.....

I can undo all four in under a minute...

Plus it allows for expansion and movement of the obs/ROR.

If high winds are predicted in my area.

I go round and give them another quick turn,just to tension the roof a bit more.

Wayne

[Merlin66]

I use similar turnbukles, but only one per side...10 sec job to unwind and release.

Benefit is you can change the pull down tension.....

[Gina]

Since I'm running on rubber tyred wheels I don't really want to screw down hard onto the wheels. In fact I would prefer to lift the weight off the wheels and having the trolley slide pins (or bolts) into holes could serve both purposes - in conjunction with something to prevent it coming out (until I want it to). If I can arrange that the weight is taken off the wheels when the trolley is parked, it will stop flats forming on the rubber tyres.

[Astroscot2]

Hello Gina, I’ve been following your progress with some interest. I built my own Observatory a few years back, its interesting seeing your progress and reading about you thinking through all the stages. What I discovered while building was that the simplest solution was normally the most effective. I would not worry too much about aluminum guide rails, wooden 6mm rails will work absolutely fine as others have mentioned as long as you have enough castors each side the roof won’t jump the rails. Also as for flats on the wheels, depends on how many wheels the weight is distributed on, I have 6 cheepo screwfix fixed wheels each side and never had any issue. th wheels roll perfectly fine...

Looking back I wished I have spent more time and worry on the exterior than anything else, my real only issue over the past 3 years is a little dampness along one corner, now fixed with 4 coats of ducks back over the summer. Don’t scrimp on the waterproofing keep the rest simple.

[malc-c]

Like Wayne I too use turnbuckles, one on each side. They haven't caused any issue with the 50mm rubber wheels - no flats, the roof has remained secure in constant 36mph winds and opening and closing the roof is quick and simple. However, they can be noisy especially in the dead of night when closing up at 3am... I'm considering replacing them with standard padlocks and clasps like that found on wooden sheds.

One thing I have seen proposed are those spring loaded bolt type catches, which are fine to stop the roof moving, but offer little security as it would be very easy to simply lift up the roof to gain entry and have it away with the contents.

[pritc]

However, they can be noisy especially in the dead of night when closing up at 3am... I'm considering replacing them with standard padlocks and clasps like that found on wooden sheds.

Add a smear of lithium grease to the threads.

For me,no more noisy than sliding the roof back at 3am.

The neighbours are used to my early morning antics.

I leave for work at 4.10am every weekday morning...

Wayne

[Bizibilder]

I got rid of the turnbuckle system as it was far too noisy - especially with a metal shed!! (No one had complained but I was concerned about the noise I was making!)

[Gina]

I haven't really given much thought as yet to fastening the roll off down but I'm getting plenty of ideas here Thank you folks

[Gina]

Looking at the roof materials etc. and taking note of the advice given in this forum. I agree that really good waterproofing is important. With potentially a couple of thousand pounds worth of equipment, an extra hundred or two spent on first class waterproofing seems good value for money. I've already decided to spend over £400 on shiplap cladding and now paying attention to the roofing. I've decided it would be silly spending £££ on good walls and then skimp on roofing. This is going to be an expensive build! Still, I/we save a lot of money by doing our own building and repairs to both farm buildings and the house (which we are, thankfully, capable of doing) so I can just about afford a good obsy/warm room.

OK, having rabbited on about costs, now to what I'm thinking of...

The EDPM rubber roofing, while expensive would provide definite waterproofing for the rest of my life. That's for the warm room. For the obsy, corrugated bitumen roofing from Wickes (with a 15 year guarantee). I shall need 6 sheets if I use full sheets and no horizontal joins. I already have 2 that were left over from another job.

Warm room roof :-

1. EDPM membrane sheet of adequate size - Shed Roof Kit, EPDM Rubber Roofing and EPDM Rubber Roofing Membrane from Rubber 4 Roofs

2. Kerb Edge Trim, this provides a waterproof edging that stops water running off the sides and back plus fascia trim - Shed Roof Kit, EPDM Rubber Roofing and EPDM Rubber Roofing Membrane from Rubber 4 Roofs

3. Corner pieces, provide neat waterproof corners - Black DIY External Corner Edge Trim / Rubber Roofing Trims

4. Gutter trim. A neat finish for the bottom edge where the rainwater goes into a gutter - Black DIY Gutter Trim / Rubber Roofing Trims

5. Corner gutter trim, as for the other corners but for the bottom edge to join neatly onto the gutter trim (same price as other corners) - Black DIY External Corner Gutter Trim / Rubber Roofing Trims

OK maybe this is going to the extreme but solves the problem of providing sealed edges and corners. Using the kerb trim at the top edge should relieve the problem of sealing the roll off roof to the warm room roof.

I'll post costings shortly...

[Gina]

Warm room roof costings :-

1. EDPM Roof Kit. . . . . . . . £67.52 inc VAT. . 1 off. . . £67.52

2. Kerb Edge Trim. . . . . . . £18.35 inc VAT. . 3 off. . . £55.05

3. Corner pieces. . . . . . . . £9.18 inc VAT. . . 2 off. . . £18.36

4. Gutter trim. . . . . . . . . . £18.35 inc VAT. . 1 off. . . £18.35

5. Corner gutter trim. . . . . £9.18 inc VAT. . . 2 off. . . £18.36

Goods total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . £177.64

Delivery (inc VAT). . . . . . . . . . . . . . . . . . . . . . . . . . £17.76

Grand Total (inc VAT). . . . . . . . . . . . . . . . . . . . . . . £159.40

They added ex VAT then added VAT, giving a total of £195.39

[Gina]

The extras (trims) come to £110. Quite a lot extra over the EDPM membrane plus adhesive. Probably don't need the gutter edge trim - I could just turn the membrane under and fix with clout nails. This is one of their recommended methods - http://rubber4roofs-px.rtrk.co.uk/CMS/uploads/896/documents/EPDM%20Shedcover%20-%20Garden%20Shed%20-%20Portrait.pdf. I think the kerb edge trim and top corners are probably well worthwhile to be sure of a waterproof job and save a lot of effort - particularly the corners. I was wondering how to do the corners so as to be neat and waterproof, before I went through the Rubber4Roofs web site.

I'm now going to adjust my SketchUp model to see how this all works out (at least in theory) before going ahead with the purchase.

EDIT... 3 Kerb Edge Trims plus 2 corners plus the sheeting kit and delivery comes to £155.01, that's £40 less and I think it'll look neater without gutter trim and associated corners.

[fwm891]

Hi Gina, Regarding the gale-proofing ideas. When I built mine I made it so the RoR when closed has 2 long bolts that go through the matting warm room wall and 2 at the end wall - I simply use wing nuts on these bolts to secure the RoR to the obsy structure...