Asbestos Cement Garage Roof Leaking

Discussion in 'Builders' Talk' started by drshaw007, Feb 13, 2006.

  1. drshaw007

    drshaw007 New Member

    Hi All,

    I'm a bit of a newbie so please be gentle.

    I have a corrugated asbestos cement garage roof which is leaking over a large area. From the inside it looks as if water is soaking straight through the cement and dripping in lots of places rather than from a seam/joint etc...

    The area where this appears to be happening has a large amount of moss on the top. Does anybody know if the moss is a result of the cement retaining the rainwater, or is the moss retaining water against the roof and thus causing the leak?

    I'd rather not replace the roof as I have little money or time. If it is not just the moss and the roof itself needs repair, does anybody have any suggestions to waterproof the roof? Would paint work?

    Thanks for your time.

  2. wardoss

    wardoss New Member

    I had this problem on a shed roof of mine. The moss has just built up over time. The sheet have likely just become porous and brittle due to age. However there is a solution. Watco and Jewsons do a roof repair compound, they are a very thick liquid with fibres in which you paint on. It covers the whole roof and prevents leaks.
  3. drshaw007

    drshaw007 New Member

    Thanks Wardoss,

    I thought it was was probably the roof that was the problem, but was hoping it was the moss. I'll have a look for that roof compound.

  4. wardoss

    wardoss New Member

    No problem, just found the product on the Watco website

    Not cheap, but cheaper than replacing the roof.

    I seem to recall the one Jewsons stock is acrypol, but not all branches stock it, if you let me know where you are I might be able to organise some for you.
  5. The Dormouse

    The Dormouse New Member

    Check whether you need to remove the moss before applying any protective liquid. To do this, I wire brushed my garage roof years ago before the asbestos scare came to light, spending about a week in a cloud of dust. I've been having occasional X-rays ever since.
  6. Legal Sparrow

    Legal Sparrow New Member

    Courtsey of a little google search...

    Do not clean the roof unless really necessary as asbestos fibres may be released during the process. If cleaning is necessary apply a moss killer (e.g. Jeyes' fluid), using a brush or spray, then remove the dead moss with a stiff broom a day or more after treatment. Do not sand or scrape the cement. The use of crawling boards should be employed when working on asbestos cement roofs, as there is a risk of the boards breaking under pressure and the worker falling through. HSE guidance Working with asbestos cement gives further directions.
  7. madidus

    madidus New Member

  8. drshaw007

    drshaw007 New Member

    Thank you all for your advice.

    I think I'll do as Legal Sparrow suggested and use a chemical moss killer first, worried that jetwashing might blast fibres into the air?

    Wardoss, thanks for your help. I should be able to find it thanks, (if not, I can always get it online).


  9. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    First things first.

    You should have cleared the moss straight away. You would then see if repairs are necessary.

    Allow it to dry out (eventually), keep it clear of moss, and you may well find that you have no further problems.

    But first things first. Get that sponge off the roof(moss).

    Mr. HandyAndy - really
  10. Legal Sparrow

    Legal Sparrow New Member

    I did have shed loads of moss on my roof. And it was leaking like yours (not too bad only dripping in a couple of places)

    I did jet wash the roof, I wouldn't recomend it, after I finished I could see pink coloured "scars" in the sheets. Hopefully the water kept any nasties away from me.

    Hasn't leaked since, though it does start to feel damp when it rains heavily.

    I'd definately go with moss killer and a broom if I have to clear it again.

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