I replaced the roof on our shed four years ago. This year I inspected it and I noticed mould on the inside - I checked the top and there are lots of holes along with a lot of bird poo.

 

Now I realise bird poo can be pretty nasty but I was hoping for more than four years. I have other sheds that appear fine.

 

I used B&Q's bog standard felt.

 

What should I do this time? Get a better felt or go for one of the plastic based coverings?

 

Or simply paint over the holes - and maybe the whole roof - with one of the sealants (Everbuild "Black Jack")?

Edited July 31, 20188 yr by gravelld

16 minutes ago, gravelld said:

What should I do this time?

I'd over-felt it with a better grade of felt. (There's a big difference in quality & price between the cheapest grade of felt and a polyester reinforced top-sheet felt)

Edited July 31, 20188 yr by Ian

I will never ever use felt for a shed roof again, Awful stuff with a hopelessly short life.

 

I use the corrugated bitumen roofing sheets sold by B&Q and many others. One shed has had that for 10 years now and as good as new.

Reccos for a "better grade of felt"?

As @ProDave says I would recommend corrugated  Onduline, I did a summer house with it on the west coast over 20 years ago and it’s still going strong ! Cheep and easy to work and you can buy it of the shelf. Another vote for not using felt. 

As above I have used Onduline and it’s very good, however, a word of warning, if not supported properly it can get soft in the sun and sag.

19 minutes ago, gravelld said:

Reccos for a "better grade of felt"?

https://www.diy.com/departments/roof-pro-black-super-shed-felt-l-10m-w-1000mm/1932699_BQ.prd

https://www.wickes.co.uk/Iko-Black-Ultra-Durable-Super-Shed-Felt-8-x-1m/p/117668

https://www.travisperkins.co.uk/Iko-Trade-Top-Sheet-Green-1-x-10m/p/652113

Edited July 31, 20188 yr by Ian

Thanks everyone, shall look into the corrugated option too.

I used the corrugated bitumen sheets from Wickes years ago and they were utter crap. Never, ever again. BiL used them on his woodwork shop too, same result. Not much of a slope tbh on either roof. They just sunk between the roof beams leaving like soggy washing up bowl sized depressions that then split. Can't remember the centres on my roof but I put extra angle irons in to have the distance the sheets were spanning. Think it ended up 18" maybe 2'. I always wondered if a ply deck first would have helped.

42 minutes ago, Onoff said:

. I always wondered if a ply deck first would have helped.

 

As per my comment above, yes sagging can occur, it did not happen on a barn roof I did years ago but it was 45’ pitch, yes if flat fully supported would be good. If it’s a shed roof the timber will exist ?.

Yes used it on 45 degree pitched roof fully supported by sarking boards.  

The 15 Year Shed felt works well for me.......the standard felt which comes with most sheds tears easily and only lasts around 5 years.