Shed roof falling apart - which option should I follow

Discussion in 'Builders' Talk' started by pateksan, Sep 15, 2020 at 11:07 AM.

  1. pateksan

    pateksan New Member

    I've been delaying felting my shed for a long time and the roof is falling apart. We're hoping to move within a year, so I am looking for ways to avoid replacing the shed before we do. I came up with a few options, I will list them in the order from "cheapest and easiest" to "costliest and hardest". The east corner is the worst - see photos below.

    1. Do nothing for another year - but I doubt the shed will survive the winter

    2. Cover with damp-proof membrane black 1200ga 3 x 4m - not sure how to secure it to the roof/sides? Just nails? Or just screws? Can I use some eyelets or washers to avoid wind ripping it at the nails/screws? The beam on the underside is in decent condition, but sagging, how do I stop a puddle forming in the middle of the roof?

    3. Cover with damp-proof membrane black 1200ga 3 x 4m but knock up a basic flat frame to nail it to

    4. Cover with felt from the roll on existing boards - some are rotten throughout so I can't really nail the felt, will lots of adhesive along all edges be enough?

    5. Cover with felt from the roll, but make a new roof but knock a basic flat frame with 3mm MDF sheets to nail the felt to - seems excessive for the task of securing it for a year.
    IMG_20200915_092214435.jpg Copy of IMG_20200915_091925491_HDR.jpg Copy of IMG_20200915_091932224_HDR.jpg Copy of IMG_20200915_092002352_HDR.jpg Copy of IMG_20200915_091430613_HDR.jpg
     
  2. Hans_25

    Hans_25 Screwfix Select

    That's in a really sorry state. Either leave it to perish, or replace roof with 18mm OSB and re-felt - if there is enough supporting timber left.
     
    koolpc likes this.
  3. pateksan

    pateksan New Member

    Cheers Hans. Would I get away with 9mm, or is it not worthwhile? 9mm is £19 per sheet and half the weight, 18mm is £30 per sheet. And the problem is that the roof is 2.62m by 1.95m so I can't see a neat way to cover it without three sheets. It seems I need two sheets cut from 2400x1200 to 1950x1200, and then third one cut from into 2400x(220 and 980), then cut the 220 part to 1950 length? Then cut two strips, say 50mm wide, from the 980mm part to join the three parts at front and back? And obviously allow 50mm overhang front and back for the jointing strips, so actually 2050x1200? I wish I could just shrink the shed to 2.4m...

    Any thoughts on just using a large plastic sheet like the damp=proof membrane? So much cheaper and quicker...
     
  4. Hans_25

    Hans_25 Screwfix Select

    9mm might work, depends on what the underlying structure its likely to flex and bend. You can get T&G 18mm OSB in 2' x 8' sheets which is ideal for this.

    DPM could also work, but is at risk of puncturing especially given the state of the timbers. Why are you even considering replacing/repairing the roof, what's your objective? May be overboard with cheapest 9mm OSB type stuff you can find them sheet of DPM. Horses for courses.
     
  5. pateksan

    pateksan New Member

    Any suggestions on how to secure the DPM to the OSB/sides of shed? I'm guessing a piece of duct tape before screwing/nailing down, then another piece of duct tape on top? Is a screw or nail better?
    If I do nothing I seriously doubt it will survive the winter. If the roof collapses then I will have to either replace the shed, or do the repair I'm considering now, but do it in horrible weather etc. The sides and corner posts seem nowhere near as bad as the roof atm but will probably deteriorate quickly now that they are exposed to water.

    Thanks once again Hans, any further opinions or ideas are welcome.
     
  6. Hans_25

    Hans_25 Screwfix Select

    If the roof collapses then its because the supporting timbers are rotten, so they need replacing. I think first you need to establish whether the issue is more superficial, or structural. In other words, what is the problem you're trying to solve.
     
  7. pateksan

    pateksan New Member

    I will get some pics inside later, but I think the mode of failure would just be individual boards falling apart, the substructure doesn't seem that bad.
     
  8. gadget man

    gadget man Screwfix Select

    Try a box of matches and a drop of petrol.
     
    Jord86 likes this.

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