Replacing garage flat roof

Discussion in 'Builders' Talk' started by DIYDave., Sep 13, 2018.

  1. DIYDave.

    DIYDave. Well-Known Member

    Hi all,
    Been trying to get around to this job for ages and really want to get it done before end of the year, just cant decide on best versus easiest (to diy) product to use

    Current roof is timber joists, 18mm planks (like floorboards), mineral felt, various patches and liquid repair attempts. Timber is all solid, felt is totally shot

    So, strip off felt, assume its torch on so no idea how cleanly its gonna come off
    Possibly treat timbers with wood preservative
    Clad over planks with OSB3, plenty of screws

    Not even considering using felt, have been looking into EPDM rubber but read that fibreglass seems to be best option. Just not sure if I want to tackle using this on first attempt on my garage. Several upstands to tackle, curved at the front, gutters with drip edges, etc. Dunno, slightly nervous to just go for it as it seems mixing quantities and weather conditions need to be pretty perfect

    So, also been reading up about a liquid system, several out there but this one stocked locally to me;

    Just seems too simple. OSB, roll mesh tape with product to joins, upstands, details, etc, Add catalyst to Desmopol, apply with solvent stable roller, 2 coats, job done

    That's it... seems too good to be true
    Anyone on the forum any experience with this product - would be interested to hear your views

    Thank you
  2. rogerk101

    rogerk101 Well-Known Member

    I would go the fibre glass route.
    I did it on my flat roof, which also had a couple of upstands, including a sky-lantern, and it's perfect.
    This is a good time of the year to do it as it's neither too hot nor too cold, so just go for it.
  3. DIYDave.

    DIYDave. Well-Known Member

    Thanks Roger for the encouragement. I’m a confident diy’er I would say and tackle most jobs (after some research where needed)

    Did you buy all materials as a complete fibreglass kit and did you purchase locally or on-line

    Again without knowing anything about the product it’s a minefield on choosing the right/best materials and as ever, wildly varying prices

    Don’t want to end up buying rubbish quality materials as I guess there must be good and not so good out there

    Thanks again
  4. KIAB

    KIAB Well-Known Member

    GRP (fibre glass) can't fault it, had it here 8 years,previous place 25 years,far superior to EPDM.

    I would remove the planks & lay 18mm OSB3 for the deck, or look at a warm roof design 11mm OSB3 100mm minimum rigid insulation, then 18mm OSB3 & GRP covering.
    rogerk101 likes this.
  5. rogerk101

    rogerk101 Well-Known Member

    I bought a complete kit.
    I just told them what surface area I needed to cover, and they sent the fibreglass matt, the resin, the catalyst, the gel coat, the gloves, the containers, the stirrers, and pretty much everything I needed.
    They were pretty accurate, as I had very little left over. The little that I did have left over, I just used to bulk up the areas that I thought could be problematic, like the upstands of the sky lantern and the area around a soil stack breather.
    There are vast numbers of good instructional video clips on YouTube, so you'll be a guru before you even start.
  6. rogerk101

    rogerk101 Well-Known Member

    Hindsight is 20:20 vision ... so with hindsight, I should have made mine a warm roof instead of the cold roof that it is currently.
    KIAB likes this.

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