Water coming through shed walls.

Discussion in 'Landscaping and Outdoors' started by Gav8452, Jan 24, 2022.

  1. Gav8452

    Gav8452 New Member

    No I don't have that, I had just seen this on some older sheds and assumed the wider the board the more chance rain would flow down the roof into gutters as opposed to running off the gable end. The felt would remain fitted as is. I think they would just nail (or could probably glue nowadays) onto the gable end boards.
  2. MRY

    MRY Screwfix Select

    Oh, so you have what's pictured in the bottom left posted Gav8452, Today at 3:59 PM.

    THat should be fine. The felt should be sandwiched between the barge board and the roof. It shouldn't leak there, the water should just run down between the felt & the board and drip off. There should not be a lot of wet going through, because it's a small area.

    Edit: Hang on a minute. What's happening here:


    It looks as though the roof surface is uneven, and there's a trough in the felt. Hm?
  3. Gav8452

    Gav8452 New Member

    It possibly does as the four sections that make up the roof are 10ft long and are only supported at either gable end, and I took the initiative to screw the four sections together in an effort to support and strengthen each other. There are no other supports. I dont think it bows much. You can imagine how difficult it was to hammer the felt nails into place with lots of movement and flexability in the middle of the roof.

    This picture shows where and how the roof is supported on the gable ends...no other support.

    Last edited: Jan 24, 2022
  4. MRY

    MRY Screwfix Select

    A possible trough indicated by the big arrow. A billow in the felt caused by distortion at the little arrow. Something to look at?

    Attached Files:

  5. Truckcab79

    Truckcab79 Screwfix Select

    If you’re not getting signs of water ingress in the roof panels then I wouldn’t worry too much about the uneven felt. So long as it’s intact and well overlapped it’ll be waterproof. Just whack a few more clout nails in so it stays that way.

    The trick to banging them in on the bouncy middle bit is to hit them once and hit them hard (within reason!)….or use galvanised staples. I don’t do it personally but seen it done many times and yet to see one come apart. Lots of shed installers do it because it takes minutes to get a whole roof on that way.
  6. DaveF

    DaveF Active Member

    I think the water is running down the shed and as it hits a joint it runs in to the joint and capillary action is drawing it slightly up in to the joint and an unprotected area of the wood where it is just saturating the wood. The answer to me would be to seal the lap joints on the outside using a clear, over-paintable waterproof sealant. It would also help if you had something to get the rain from the roof away from the sides.
  7. Gav8452

    Gav8452 New Member

    Well spotted, I'll check that. I think it looks that way because the board on the gable end wasn't playing due to the two layers of felt underneath and hence the billow.

    The roof sections are fitted and supported by strips of wood. Diagram below looking at the gable end from the inside. Red outline is the roof sections and black are the supports. IMG_20220125_162914.jpg
  8. Gav8452

    Gav8452 New Member

    So we are getting water through the roof at the other end. Always a small amount of water on floor after rain. I've put it down to the roof nails not being seated properly (that bouncy roof thing) or possibly a small hole which I can't see or find. Reckon the felt is the cheapest going so I've got a tarp over it at the moment to help dry out before replacing...never really been that concerned about it as that's an easy fix.
    Last edited: Jan 25, 2022
  9. Gav8452

    Gav8452 New Member

    Hi Dave, thanks for your post. This is what we think is causing the issue. Combine that with holes, cracks or splits within the joins and it would explain the issue. We've had people round to look at it and they suggested painting it again, paying particular attention to the joins. I think I'm now onto coat 7 and believe it's making a difference. Bit concerned though that it's not a permanent solution and the thought of having to paint a shed half a dozen times a yeat defeats the purpose.
  10. MRY

    MRY Screwfix Select

    It should not leak like that through small holes. My log shed, where I keep dry logs, has got much worse problems, but it does not leak like that!

    I do like your gambrel/Dutch Barn roof. The reason for mentioning the little deflection in the felt is that if water runs down the roof, it may be channeled somewher it shouldn't be.

    Can uou experiment, by going and having a look to see where the first leaks appear when it starts raining?

    I don't think more coats of paint should make a huge difference, unless you're adding so much it's acting as caulk.

    Edit: If you find you need to reinforce the meeting point of the framing battens in the roof, and easy way is to use cheapo hinges, they adjust (of course) perfectly to the angles, and the other fixings stop the roof actually using them as hinges!
  11. Gav8452

    Gav8452 New Member

    That was literally my plan!

    I got thinking though and tried a little experiment. So I got the garden hose out and sprayed water on the side that is worst affected, ensuring I was avoiding the roof and spraying down towards the ground, not forcing water up through the joins. Took a couple of minutes before the first sign of water started to appear on the inside around the central area where I am having the issues.


  12. DaveF

    DaveF Active Member

    Yes, I mean the paint is just going to crack and you have the problem back again each year. I would strongly consider a sealant. There are some waterproof clear sealants that you can paint over. I forget their name.
  13. MRY

    MRY Screwfix Select

    So it's damp but not (yet) dripping. Perhaps there are gaps around the knots, where they have shrunk?

    As an aside, if you want to knock nails into bendy wobbly things, get someone to hold a heavy thing like a club hammer or piece of timber against the other side of the thing while you put the nail in. No bounce then.

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