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Membrane fail on unit block roof - $40,000 question

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  1. #1
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    Default Membrane fail on unit block roof - $40,000 question

    Our unit block was built in 1974 with a flat concrete roof covered with a torch on bituminous (guess?) membrane. The integrity of this had been questioned so we called quotes to have remediated. Went with a reputable commercial building services company who considered it was not necessary to remove the existing torch on and that it could simply be covered with a few coats of Ardex Hydrepoxy WPM300. This was stated to remain reasonably flexible so it would ‘give’ a little as the existing substrate moved.
    Accepted cost was $40,000, with a 10 year guarantee by the company on installation in addition to 20yr manufacturers warrantee.

    After 10 months there are a number of cracks and areas where the new membrane is lifting and peeling off - it has set rigid and inflexible whereas I thought it was to remain reasonably flexible.
    The company inspected and considers their supplied product is not at fault and the problem is due to the substrate adhesion failing and ‘forcing up’ the membrane which has lead to it cracking and splitting. The evidence this is what happened was allegedly the slightly discoloured underside of the flaking pieces indicating some bitumen adhesion.
    I call BS on that as the ‘adhesion’ is only microns deep, possibly just where the primer has soaked into - hardly strong enough to force the Ardex up and crack. See pics
    After some ‘healthy discussion’ company has agreed to do 6 month patch jobs for up to 2 years, so they seem to be trying to walk back from their previous 10 yr undertaking.
    I have not pushed the point soas not to prejudice getting at least the first 2 years remediation sorted, but wiuld appreciate some informed assessment of whether the original solution was ‘fit for purpose’ and whether I an being unrealistic in the performance expected for $40k.

    aac36ed2-5b13-428d-b7de-fe4c7cacb1e5.jpg
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  2. #2
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    I'd be of the opinion that the old membrane would have to be removed & the whole roof redone correctly, their recommendation that the old membrane remain hasn't been successful & you are going to suffer a loss because of their poor investigation or advice, one would think they would have insurance to cover that sort of thing, don't expect them to admit liability for it, because they would not under the terms of their insurance policy .

  3. #3
    Community Moderator phild01's Avatar
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    I remember a university that had a concrete 70's bituminous concrete roof redone in the 90's and it wasn't anything like the cover up done here, they rolled some type of membrane over the entire area.

  4. #4
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    2 different products with different expansion rates under heat. In addition to that bitumen softens under heat which would allow for the epoxy to lift away.
    Frankly I can never see it working as installed. I suspect they are playing the waiting game hoping you will move.

    Only been involved in one roof done like your style that had a thick layer of rubber/PVC compound rolled out onto roof and welded at seams.
    Edit: Actually there was a second. Disconnected/raised the aircons and a low 15deg roof of tin was installed on the building.

    Probably bring it up with whatever body corp is active. Pay for a separate inspection, and look at trying to get as much of a refund as you can.

  5. #5
    Member wspivak's Avatar
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    Absolute @@@@@@@@.

    I'd contact Ardex and ask technical people if the WPM300 is suitable for the above application (hint - it's not). Get it in writing from Ardex and then you've got the "reputable" building services company by the short and curlies.

    Also - take a look at the product data sheet (https://ardexaustralia.com/product/ardex-wpm-300/) - nowhere does it state that it remains flexible or that it can take long term UV exposure.
    The WaterStop Shop
    waterproofing supply professionals
    Oakleigh, VIC

  6. #6
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    Thanks guys,
    I have emailed Ardex with the initial proposal by the company specifying Ardex WPM 300 and a video of the current failure, and asked whether this was a ‘fit for purpose’ solution. Will see how that goes.

    Cheers
    Ron

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