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  1. #1
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    Default what sort of ceiling paint

    I have a little problem with my ceiling- the exterior was treated some time ago, but the paint ins ide still keeps coming off- no visible damp,but the cotton woolly bits push the paint off, any ideas about what sort of paint to use, Im contemplating water based pool paint as nothing else seems to work (desperate measures)

  2. #2
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    We have the same problem with our painted, concrete roof.
    The exterior paint gets a bubble, then the bubble fills with rain water and the water slowly leaches into the concrete. When the concrete is moist enough the paint eventually absorbes it and it flakes of, creating a dust like powder.
    Overtime the bubbles on the roof get bigger and there is more moisture absorbed.
    It doesn't take a lot of moisture either.
    There are two ways I know of dealing with it.
    First, is to re-paint the roof with elastomeric paint. This involves scrapping the old bubbles off. Manufactures recommend doing two coats, typically with-in hours of each other.
    The other alternative is to rubberize your roof. This is more costly but in the long run will last longer, if installed properly.

  3. #3
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    the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months

  4. #4
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    You might try drilling small holes in the ceiling to allow the concrete to vent. It was done on my south coast home years ago and worked well.

  5. #5
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    MASONRY AND CONCRETE - If efflorescence or cement dust is present on masonry and concrete, it should be removed by etching with a 10% solution of muriatic (Hydrochloric acid) solution; wear protective goggles and rubber gloves. Flush off surface, after etching, with clean water and allow to dry.
    On surfaces where muriatic acid cannot be used to neutralize the efflorescence, sand, scrape, and wire brush and coat with Masonry Conditioner before painting.
    Prime with latex primer and allow to dry four hours before topcoating. Rough concrete and haydite blocks should be filled with Latex Block Filler. Allow to dry overnight before priming.

    So in a nutshell clean, seal, prime, paint. None which will be any good if your roof leaks.

  6. #6
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    Quote Originally Posted by jrhartley View Post
    the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months
    Could it be that there was too much salt in the sand that was used for the original plastering? I am told that this might cause the continuing problem.

  7. #7
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    Quote Originally Posted by jrhartley View Post
    the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months
    It sounds like you still have a leak somewhere. Check around the edges on the roof. If you have a tank on the roof it could be a like in the piping supplying it.

    I had the same problem but after we sealed the roof and fixed some plumbing it all but went away. It still happens when it rains a lot and I think it is probably a downspout coming from the roof is not sealed good.

  8. #8
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    Whirleybird has a good point here, salt in the sand/ cement mixture. If there is salt present it will create efflorecence on a larger scale.
    I would not recommend "drilling holes" to "vent the ceiling, this in itself does not make any sense to me and I can't image how this would resolve any problems with water retention.
    To fix the problem you MUST repair where it originates from, this is the outside/ exterior of your roof.
    jr, I know you said it has been painted with "specialised rubber paint", this is elastomeric paint. I would have to assume that the paint is not doing its job properly, or that it was never properly painted correctly. You can't paint under direct sunlight (it cures too fast), you can't just simply roll it on quick (this doesn't allow for a thick consistant coat), you can't walk on it too much right after its been painted (this is usually when problems occur to putting the second coat on, and again manufactures recommendation is ...I think...3-4 hours after the first coat).
    Take a look yourself up on the roof, if you can and look very closely to the existing "rubberized" paint. Look for tiny bubbles in the paint or "hairline" cracks in the paint.
    Your will be wasting your time and materials redoing the interior, without correcting the problem at its source.

  9. #9
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    Quote Originally Posted by bob saunders View Post
    MASONRY AND CONCRETE - If efflorescence or cement dust is present on masonry and concrete, it should be removed by etching with a 10% solution of muriatic (Hydrochloric acid) solution; wear protective goggles and rubber gloves. Flush off surface, after etching, with clean water and allow to dry.
    On surfaces where muriatic acid cannot be used to neutralize the efflorescence, sand, scrape, and wire brush and coat with Masonry Conditioner before painting.
    Prime with latex primer and allow to dry four hours before topcoating. Rough concrete and haydite blocks should be filled with Latex Block Filler. Allow to dry overnight before priming.

    So in a nutshell clean, seal, prime, paint. None which will be any good if your roof leaks.
    That is exactly the only way I know how to deal with your difficulty. We had much the same trouble. No roof leak anymore!!! But clean, seal, prime, paint.... we primed several times with much drying time between and it seems to have solved it for us. Good luck!!

  10. #10
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    Quote Originally Posted by reese_in_va View Post
    I would not recommend "drilling holes" to "vent the ceiling, this in itself does not make any sense to me and I can't image how this would resolve any problems with water retention.
    To fix the problem you MUST repair where it originates from, this is the outside/ exterior of your roof.
    As I said, drill holes in the ceiling. I didn't say drill holes in the roof. One is inside, one is outside. Obviously the water entrance must be addressed first. But once the water is inside the walls, ceiling or any other structure, it has to be given a way out. That's one of the reasons paint blisters and bubbles, because of water exiting. If ambient humidity in the ceiling is equal to the outside humidity, there is little problem. The problem is when the humidity/moisture is higher in the concrete than the surrounding area. All forces tend toward equalization. Drilling holes in the ceiling worked for me.

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