Roof material

[Aoraki]

Hi all, I have just started building my obsy and would like your oppinion on roofing materials. My initial thought was to go with a good quality felt, then it was suggested I had a fibreglass over timber roof.

After a bit of surfing the web I came across this product , has any one used it or have any further suggestions? It looks a reasonable product for the money.

I should perhaps say my obsy is 8' x 14' and will have a RORO roof coming off the 14' side.

I will have to start a build thread soon, presently on weekend 2 and have completed the following;

Day 1

large pampas removed from site

ground cleared and levelled

hole for pier dug

Day 2

concrete plug poured complete with anchor bolts cast in

6no 2'x2'x2" slabs placed and levelled

Day 3

all 6"x2" floor joists installed

rear wall fabricated, clad and installed

Day 4

remaining 3 walls fabricated, clad and installed

openings for door and windows made

dividing wall fabricated and installed

Day 5

2" conduits run fro warm room to scope room

2" conduit run from obsy to house (well half way!)

2.5mm SWA cable run from obsy to house, again half way

I have taken pictures which I will get posted soon.

Andy

[Freff]

Hi Aoraki and welcome to the SGL.

I'm not familiar with the product you linked to but I'm sure someone will be along with the answer.

You have certainly come to the right place, there are loads of builds done or in progress on this forum.

[Gina]

Welcome from me too That rubber stuff looks very good and probably easier to apply than felt but it's a lot more expensive. May work out cheaper in the very long term though - if you expect to be using it for 50 years! I shall be using roofing felt for mine, having costed the alternatives.

[JamesF]

Yes, I reckon it's at least three times as expensive as felt. I'm not sure the fact that it lasts longer makes it worth it unless you know you're going to be in the same place using the same observatory in forty-odd years time.

James

[MikeP]

Squirrels are a nuisance where I live. If you have them, would this product stand up to their claws over a number of years?

Mike

[swag72]

I have wondered long and hard about what to use for the roofing for my obs - Currently have 4 walls and a door up, onto roof ideas now.

I am going for 2 very think pieces of tin, with about 1.5 inches of insulation foam between them. Ready made, they are 68€ for a 1m width length. I need 2 of them and they come with a very nifty system for the join. They'll be light and waterproof!

[Gina]

You certainly wouldn't have any problem with squirrels

[pete_l]

I can't say I've ever used this product, but it does seem to have some advantages.

Since you'll be rolling the roof on/off, there's bound to be some flexure in it - it can't possibly be perfectly rigid. This sort of stuff might be able to compensate for the lack of rigidity. Since ordinary roofing materials aren't designed for roofs that move, it's difficult to know how a traditional roofing material would bear up.

Having said that, it does sound expensive - and having to glue it on could be complicated. Also a quick goole for "epdm roofing" turns up some other suppliers of similar materials - so some shopping around may pay dividends.

[callump]

I used Wickes Bitumen Corrugated Sheet - Bitumen Corrugated Sheet - Bitumen Roofing - Roofing -Building Materials - Wickes

Its been up for over 10 years and is showing no signs of degradation.

Wickes shingles look pretty too.

/callump

[Gina]

Yes, I considered using that. Works out more expensive. Also, not recommended for slopes less than 5 degrees and my design uses a slope of 3 degrees. OTOH I am a bit worried by the movement/bending of the roll off roof with roofing felt. I may yet change my mind on that. I've used the bitumen roofing before, as well as corrugated plastic and galvanised iron. But I've never used felt before so a bit wary of it. I think it should be fine on the warm room roof.

[callump]

My roof is about 15 degress pitch, i think.

I did not want the added weight and cost of a wooden surface (which you need if you are using felt) - the corrugated sheet is nailed direct to the rafters. The roof structure is all self supporting, so the roof cladding material does not need to provide any structural integrity.

/callump

[Helen]

Our new roof uses the bitumen sheeting rather than a solid wooden roof with felt. Its much much lighter than the previous build!

I'd advise against the shingles - they are REALLY heavy.

Helen

[laser_jock99]

I used Wickes Bitumen Corrugated Sheet - Bitumen Corrugated Sheet - Bitumen Roofing - Roofing -Building Materials - Wickes

Its been up for over 10 years and is showing no signs of degradation.

Wickes shingles look pretty too.

/callump

I used the same stuff. The manufacturer is Onduline seems okay to me so far- more expensive than felt but looks classier when done.

Onduline Roofing Sheets - Onduline Stockists - Onduline Sheeting

Coroline is the thinner/cheaper alternative

Coroline Roofing Sheets - Coroline Sheets - Coroline Roof Sheeting

But I have been able to climb around on my Onduline roof (all 14st) without going through it! There's no flat wood sheet under just the wooden frame. If your rollers are good then weight will not be an issue.

Onduline Roof

[Gina]

I'm thinking seriously of changing my design for the roll off roof. Using an apex design with corrugated bitumen. But I'll keep the "flat roof" pent style for the warm room. The ROR can have a 10 degree slope thereby avoiding having to use the heavy OSB. Have to say, I was never really happy with the design of the ROR with OSB and felt.

[Aoraki]

Thanks for all your thoughts. I not sure about using felt though, life span seems limited and what with flexing in a ROR I'm concerned about cracking, there's a fair bit of flexability with rubber. I have found other supplies of EPDM and they all appear to be in the same ball park of £140 - 160 inc vat. For peace of mind I think I'm going the EPDm route, I will keep you updated!

[Gina]

I think that's a good decision - the roof will be protecting a lot of expensive equipment and peace of mind is worth a lot

I have decided to change to a pitched (apex) roof with corrugated bitumen sheets for the obsy ROR to save weight and provide better rigidity. Weight is a very important factor - I have to get the stuff lifted up to 6ft in the air! And the lighter the roll-off is the easier it will be to move. I already have 2 unused bitumen sheets so that'll save a bit on the cost.

I'm also beginning to think of using that rubber roofing on the flat roof of the warm room. I'm not very happy having joins in felt on a roof with only 3 degrees of slope - a single sheet of waterproofing would guarantee a waterproof roof. I think the "5x7 shed" size should be sufficient with a sheet size of 2.60m x 2.25m (8' 6" x 7' 4"). That would give 267mm extra on the width for fixing (over 5" each side) and about 600mm extra on the length. That costs just under £70 as compared with somewhere near £40 for a roll of good roofing felt plus adhesive and clout nails. So... I'm thinking an extra thirty quid would make for a much better job. OK so I've already bought a roll of felt but we need a roll for repairing the goat shed roof so it won't just be hanging about

I decided a while back not to skimp on this build - my experience in life generally is that going for the cheapest option turns out to be false economy and that spending a bit extra works out cheaper and better in the end.

[Aoraki]

Gina, my thoughts about joints on low angle roofs mirror yours. I'm sure you're better off with one piece, the fewer places to leak the better!

Ps your build thread is in inspiration to us all! I really need to start my build thread before the sheds finished.....

[Gina]

Gina, my thoughts about joints on low angle roofs mirror yours. I'm sure you're better off with one piece, the fewer places to leak the better!

Makes sense to me

Ps your build thread is in inspiration to us all!

Thank you

I really need to start my build thread before the sheds finished.....

That would be good - it's always nice to read other people's builds and designs

[Gina]

Right... I have a question for those using the corrugated bitumen sheets. How are you sealing the corrugations at the eaves to stop wind blown rain (or snow) getting in?

[Gina]

Well, I can now report on how good a solution it was to use the the rubber roofing having just put it on my warm room roof

It was relatively easy to fit and the rubber is nice and pliable with no chance of cracking or breaking. I'm very pleased with my decision to use it and for Aoraki's original post about it. The result looks nice and tidy

Applying the adhesive to my OSB base and wooden sides was easy. I used a long handled small paint roller - the sort used to get behind radiators. This allowed me to reach the whole area of the roof without climbing onto it. Also being narrower than the standard paint roller, it could be put straight into the pot of adhesive.

I used an old paint brush (well worn down) to get into awkward bits such as the edges and corners. It wanted a good thick coat of adhesive to stick well - not spread out thinly like paint. Corners and other places where the rubber wasn't lying flat down stuck fine if left for a while for the adhesive to dry a little.

[laser_jock99]

Right... I have a question for those using the corrugated bitumen sheets. How are you sealing the corrugations at the eaves to stop wind blown rain (or snow) getting in?

I ended up pushing bits of grey foam in the gaps. More worried about snow ingress up here than rain. Has a nasty habit of even traveling upwards to find a way in.

[callump]

Right... I have a question for those using the corrugated bitumen sheets. How are you sealing the corrugations at the eaves to stop wind blown rain (or snow) getting in?

I don't have anything - but then a fairly large overhang, and a reasonable pitch. I have not had a problem with wind or snow blowing in, and its fairly sheltered east/west (the way the corrugations run).

Callum

[Helen]

You can get specially shaped 'foam' eaves fillers

Helen

[Gina]

I've used eaves fillers with the 3" corrugated plastic and galvanised iron but the bitumen is NOT 3" pitch, it's 95mm - about 3.75" and the eaves foam filler wont fit So far I have been unable to find 95mm pitch eaves filler.

Yes, snow is the problem rather than rain. We have ventilators in the roof of our big shed and the snow blows in there but the rain very rarely. Yes, snow will go uphill!

[misterp]

Hi All,

I used a sheet of rubber from www.rubba-seal.co.uk.

Brilliant, doesn't tear, one big sheet (my roof is about 2.4mx4.5m)easy to fit.

I would recommend it 100%

Ian