Garage Roof Advice

Got a large (bigger than double sized) garage with a badly leaking felt roof. The boards are largely shot (I think the previous owner used a fibre type board in places). The fascias are also knackered and need replacing with PVC-U. From what I can tell the joists and firrings are all OK although they get quite wet in bad weather. After procrastinating for a year or two am determined to get the roof sorted this year.

The garage is tied into the house and the roof area is a weird shape (A birds eye view would show it tapering in what could be described as a trapezoid shape). Thinking of taking on the work myself but don't want to charge forwards and get into a muddle. I hope that someone with experience can provide me with some guidance:

Most of the work will be completed by me, have the option to call in some help but will largely complete on my own. I wonder if this is practical or is this likely going to be too much for one pair of hands?

Looking at EPDM as a solution but the weird shape does concern me. Not sure how the external corners can be made to work on such an irregular shape. Has anyone dealt with corners that are off 90 degrees when fitting EPDM, if so how did you get around this? Perhaps this issue means that EPDM is a non-starter?

Thinking of replacing the fascias and guttering first before re-sheeting the roof (just to break the job into manageable chunks). On the forum, I can see others talk about prising up the felt and pushing the fascias into place. Is this a sensible option or am I storing up trouble for myself when it comes to re sheeting and adding the EPDM?

Dunno
But when I knew my extension roofer was due - to replace a flat felt roof, I set too and changed the boards for UPVC
I levered the old felt up, being careful to not break too much of the horizontal part, and removed the wooden boards, fitting plastic. Then folded the old roof back. It wasn't hard and didn't leak in the short time that the roofer took to come. If you wait until better weather then a cheap bulge tarp and some bricks/sandbags/ water containers can be used to hold the tarp in place

It is easy to replace a roof with the modern equivalent of corrugated steel sheeting. It is a part box section, in two metal thicknesses and various colours and galvanised under the finish coat. It survives for many decades, but (like most of these types of covering) only supports being laid in one direction. I more or less managed my 24 x 12' garage on my own, just someone to pass up the panels as I laid and fixed. The panels are fixed via the panel surface in contact with the timbers (the bottoms) with special self sealing waterproof fixings, so no leaks. Rather than shorten the panels, you just increase the overlap to take care of the surplus. I removed the old and replaced with new an easy days work.

Tigercubrider said:

Dunno
But when I knew my extension roofer was due - to replace a flat felt roof, I set too and changed the boards for UPVC
I levered the old felt up, being careful to not break too much of the horizontal part, and removed the wooden boards, fitting plastic. Then folded the old roof back. It wasn't hard and didn't leak in the short time that the roofer took to come. If you wait until better weather then a cheap bulge tarp and some bricks/sandbags/ water containers can be used to hold the tarp in place

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Sounds like a plan, thanks for your comments.

Harry Bloomfield said:

It is easy to replace a roof with the modern equivalent of corrugated steel sheeting. It is a part box section, in two metal thicknesses and various colours and galvani,sed under the finish coat.

Click to expand...

Thanks, Harry the roof tapers (see attached) so the edge would need to be cut at an angle, am concerned about beasties gaining entry via this area. I guess I could use expandable foam or similar to stop this, but I want a neat job.

The pitch is low 1:40 so am concerned about condensation which I know can be a problem with metal, how do you find this?

Also, can you walk on your roof? I need to access mine for maintenance purposes.

BathDIY said:

Thanks, Harry the roof tapers (see attached) so the edge would need to be cut at an angle, am concerned about beasties gaining entry via this area. I guess I could use expandable foam or similar to stop this, but I want a neat job.

The pitch is low 1:40 so am concerned about condensation which I know can be a problem with metal, how do you find this?

Also, can you walk on your roof? I need to access mine for maintenance purposes.

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I actually used it for both my garage and a decent sized workshop behind it - two separate roof areas, the thinner version on the grage. I can walk on both, but the garage roof can be dented if too much foot pressure is applied in one place. Easy to avoid, or spread weight with a board. I would not suggest putting a ladder on it, without making up a special board for the job.

I used to suffer condensation on the garage roof, when it was asbestos, but only when when there was a frost. I insulated it which prevented it completely and I retained the insulation when I replaced it with metal. I have lots of tools in there, including a lathe and no sign of rust anywhere. Fabrics etc. will attract moisture in an unheated shed or garage.

For insulation, I bought several 8 x 4 x 1.5" panels of flame-retardant expanded polystyrene insulation. just cutting it down to the width between the roof joists and wedging it in place. Which I got from a specialist supplier, it cost about 20% extra for the flame-retardant version.

To seal the open ends, if the panels are cut at a right-angle, you can buy a ready made, ready profiled item. It is like a dense sponge, which you trap between the underside of the panel and the wall or surface it rests upon, but that would just not work cutting the panels at an angle.

Harry Bloomfield said:

I actually used it for both my garage and a decent sized workshop behind it - two separate roof areas, the thinner version on the grage

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Can I ask who you sourced the roof from?

My roof is tied into the house, what about noise do you see problems with a rattle when it rains?

My conservatory has a triple wall plastic roof and is a lean too
It backs onto the dining room/through lounge and my bedroom

It makes a noise in heavy rain but I find it cathartic
Presumably steel is quieter

BathDIY said:

Can I ask who you sourced the roof from?

My roof is tied into the house, what about noise do you see problems with a rattle when it rains?

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It was a small local builders merchant - I was passing on route to a job with spare time, so dropped in to see what they had for roofing material. Having researched and costed it, I rang and ordered.

Obviously I don't live in the garage/workshop - yes rain is noisy, but I'm one of those who loves the noise of the rain. It is only noisy when it is really heavy.

Thanks for your help everyone.

Hmm not keen on rain noise myself, I think this am more inclined to go to EPDM.

Have done a little research online, some articles talk about the risk of shrinkage? Presumably, this is more likely on a larger roof like my 9m X 6m garage roof?

Has anyone fitted EPDM on a larger roof? Have you seen any issues, how did you avoid issues of this type?

hello,garry malvin

The first and foremost step of repairing a garage roof leak is to identify the actual reason that is causing the problem. and then second step is you have to find the best replacement that is available in the market (obviously going by your budget and need). Then re-assemble it to the roof. And your work is DONE!