What type of roof covering for wooden cabin.

[GlenM]

I'm new to the forum and would gratefully appreiciate any help offered.

A couple of years ago I built one of those 'log cabins' in my back garden as a way sort of home office / games room. To fit in its space we had the cabin custom built and to keep in with the neighbours the roof was kept as low as possible so the pitch is low. Roughly 10degrees. It came with felt tiles that we fitted and it seemed to be ok but over the last few weeks it started to leak near the bottom of the pitch. Long story short but I ended up taking down the false ceiling inside and sure enough it has been leaking over a section about 500mm square. As the weather has been very bad I removed all of the felt tiles and have temporarly fitted a thick plastic sheet to protect the roof.

I am now looking for a new roof covering. I think the original problem came from the felt tiles not being designed for use at such a low pitch. The roof is made from 20mm thick tung in groove pine boards which I have treated with wood preserver so while they have got wet they seem fine. I think the way foward is a standard felt roof but this cabin cost enough to build that I want to protect it with something better than cheap shed felt.

I was thinking of running bitumen into the joints in the wood. Then fitting a heavy duty felt. Would it be worth leaving the plastic sheet under the new felt? Looking into it myself I've came across multiple layer felting systems that may prove better. There are so many options on the market that I'm not sure where to start and would appreiciate any help or advise available. The total area to cover is roughtly 3.5x3m The roof is a mono pitch running on the length.

 

[ladylola]

I'd dispense with the tiles for sure.
Multipule layer felting systems would be the way to go or maybe you may wish to go for something else such as a corrugated covering http://www.woodhousestables.co.uk/onduline_roofing/onduline.html
I've done my workshop roof and walls with this and found it to be fine with no problems.

 

[cotswoldbuilders]

One peice epdm, fully adhered to boards.

 

[GlenM]

Thanks for the advise. I like the look of the corrugated cover, never thought of that before. Seem quick and easy to install. I'm sure the epdm would provide a 100% cover and maybe look better but to me it seems something tricky to install. If I go down the route of the corroguted cover would I need to put something under it to ensure the wood is protected?

 

[ladylola]

There's no real need to put anything under it at all really in the same way that there's no real need for felt under tiles, it'd just be a sort of belt and braces type of view.
When I built my workshop I used something like this under the sheeting- http://www.screwfix.com/p/breather-foil-for-timber-frame-1350mm-x-25m/37037

If you do go for the corrugated sheeting have a shop around , the link was just to illustrate the product. Also note that there are two versions of this stuff coroline and oduline both are basically the same kind of thing but they have slightly different profiles meaning they don't mix too well.

 

[HH1]

As mentioned, EPDM sheet.

Easy to install, it's just glued (with special adhesive) to the wood.
Trim pieces are used at the edges, but it is possible, depending on the style of the edge of the roof, to make something yourself that would do the job.

You mention gaps between the wood, these might show up as lines on the sheet, I would consider putting sheets of plywood onto existing roof (glued and/or screwed) to give a smooth surface the the EPDM.

I have used this on a small compressor hut as a test to see both how it looks and performs. When it comes time to re-do the garage/shed this is what I'm going for.

There are videos on utube and the like showing the fitting process.

If you decide to go down the road of felting, consider 2 layer system, underfelt then heavy duty mineral felt. Usual "shed felt" that you can spit through is just not worth it.
Torch on is said to be best but never done this so can't comment.