Bubbling Paint in Bathroom

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Networkn
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#2930378 16-Jun-2022 13:40

timmmay:

Eva888: We have the same problem on an exterior wall. Saw bubbles forming after painting with Resene and when we popped them they were filled with water. Also the bubbles weren’t all over, just in some places. No logical reason. I have no idea what caused it.

I had bubbles outside. In our case it was that we had weatherboards made of very oily wood and they weren't prepared properly. The solution was to strip the entire house and prime with an oil based primer / sealer - Dulux 1-step oil based. Spot fixes are temporary only, and if you do them you should ideally do a whole board not just the spot.

The original issue started only pretty much very near the shower, but by the time we had a chance to find a painter and other things, it was about 18 months later and pretty much the whole ceiling had blistered. The issue accelerated significant once the first bubble popped (on it's own) That further supports our view that the moisture isn't coming from the other side of the gib, as that's multiple bits of gib and distance-wise, over 2.5m.

networkn

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#2930386 16-Jun-2022 13:59

eracode:

It may not be this exact paint your first guy used but Zinnser is the brand. I haven't but friends have used their products. Their range seems to have a great reputation for uses like priming over varnish before painting.

Zinser, yes. That is the stuff the latest guy used. He was very insistent about the 'right' kind of paint for bathrooms and thought the prior guy who had multiple attempts to fix it, didn't even use proper bathroom paint.

I can't tell you how discouraging and frustrating having spent this much time and money to get this bathroom sorted, to be back with the same initial issue again, is.

1101

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#2930406 16-Jun-2022 14:22

networkn:

Zinser, yes.

Ive used Zinser in my (very wet) laundry , and outside . Its just a brand , they have many types of paint . The Zin anti mold paint works great to stop mould .
Almost zero prep my the laundry (no sanding) , it worked regardless . It was summer & dry when I painted though .
The smelly solvent based paint seems to stick better compared to water based paints .

You mentioned Jib a few times. Is the ceiling Jib ?
Perhaps it wasnt bathroom rated , what ever it is.

If its damp coming through the jib/whatever , then painting over slightly damp ceiling could be part of the issue ?
Perhaps wait untill summer when everything is really dry might be an option ?

networkn

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#2930410 16-Jun-2022 14:27

1101:

Perhaps wait untill summer when everything is really dry might be an option ?

I am assuming it's gib.

The issue persisted through a summer.

I don't believe moisture is coming from the other side of the gib considering the area that ended up being affected in the end before it was stripped back and repainted.

networkn

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#2930413 16-Jun-2022 14:35

lxsw20:

Probably a pigmented sealer. Last I checked it was the only thing you can use on aqualine gib as an underseal. It smells and it's not truly dry until the smell is pretty much gone.

A bit weird you got a big bubble after the first shower, water damage isn't that instant.

It's really weird. An hour after the shower, you can't see any evidence of the issue (for a while at least).

When I spoke to the most recent painter about the fact the issue has come back, he said he will reapply zinser, and then wait longer before applying paint.

So, another week or so without our ensuite.

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#2930418 16-Jun-2022 14:49

can you get a pic of whats above the bathroom in the ceiling, also include the bathroom fan ducting. it would be interesting to get a moisture probe up there.

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#2930421 16-Jun-2022 14:59

tweake:

can you get a pic of whats above the bathroom in the ceiling, also include the bathroom fan ducting. it would be interesting to get a moisture probe up there.

I think we have one or so from when we were originally looking to see if there was a moisture problem up there, but nothing recent. It's basically framing, pink bats and what looks like gib up there.

I assume you want to see something recent?

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itxtme

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#2930423 16-Jun-2022 15:08

lxsw20:

A bit weird you got a big bubble after the first shower, water damage isn't that instant.

100% - There is something fundamentally wrong the substrate that is being painted if a bubble appears immediately. Does the area feel spongy to the touch? Have you got a pic of the bubble you had appear after it was painted recently?

tweake

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#2930424 16-Jun-2022 15:09

networkn:

tweake:

can you get a pic of whats above the bathroom in the ceiling, also include the bathroom fan ducting. it would be interesting to get a moisture probe up there.

I think we have one or so from when we were originally looking to see if there was a moisture problem up there, but nothing recent. It's basically framing, pink bats and what looks like gib up there.

I assume you want to see something recent?

recent is better but anything is a good start. its a lot easier to visualize if i can see what your dealing with.

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#2930426 16-Jun-2022 15:13

tweake:

recent is better but anything is a good start. its a lot easier to visualize if i can see what your dealing with.

I'll try and post something later tonight after my wife gets home, I think it's her camera she took the photos with.

We can throw a kid into the area if required, but access it via a wardrobe which is full of boxes.

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#2930428 16-Jun-2022 15:17

itxtme:

100% - There is something fundamentally wrong the substrate that is being painted if a bubble appears immediately. Does the area feel spongy to the touch? Have you got a pic of the bubble you had appear after it was painted recently?

I'll see what I can do to get a photo of the issue. I have a photo, but it's poor quality, lighting and position of the bubble made it quite hard to get a decent picture of the problem.

tweake

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#2930429 16-Jun-2022 15:19

networkn:

We have a very powerful extractor fan, pretty much the most powerful one we could find, it supposedly extracts about 4 times as much steam etc as what our old one did.

i don't like to jump to conclusions but there is a good chance this is actually the cause of the problem (assuming its moisture making the pain come off). if there is a bad join, split in the ducting and especially with a powerful fan (and typically undersized ducting) that your getting moisture from the shower blown on the back side of the gib. not enough to cause condensation in the roof space, but enough that the gib soaks it up and the roof cavity heat pushes it through the gib. with normal paint moisture can go through and dry, but bathroom paint will stop it.

easy test would be a moisture meter and see how damp the gib is.

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#2930815 17-Jun-2022 09:34

tweake:

i don't like to jump to conclusions but there is a good chance this is actually the cause of the problem (assuming its moisture making the pain come off). if there is a bad join, split in the ducting and especially with a powerful fan (and typically undersized ducting) that your getting moisture from the shower blown on the back side of the gib. not enough to cause condensation in the roof space, but enough that the gib soaks it up and the roof cavity heat pushes it through the gib. with normal paint moisture can go through and dry, but bathroom paint will stop it.

easy test would be a moisture meter and see how damp the gib is.

Where do I get a moisture tester from and how much would it cost?

It's worth noting we replaced the extractor fan after having the problem the first time.

mdf

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#2930819 17-Jun-2022 09:53

Frustrating!

It's an odd one. It sounds like the latest painter did everything right so it's surprising it has bubbled so quickly - even non-bathroom paint should survive a little bit of steam exposure. And then even more suprising that a bubble appears during/after showering but then disappears again (or have I misunderstood that?).

I'd be inclined to do a little more investigation before repainting if you can manage it. If there is another issue going on you will just end up back in the same position:

- Does the bubble appear and disappear after showering, or is it just more obvious with steam on the ceiling (flaws are much more obvious when damp)?

- Climb up a ladder and shine a torch along (i.e. parallel to) the ceiling. Any obvious flaws, sagging or joins in the gib/ceiling?

- If you shower without the fan on, any issues?

- If you have the fan on without the shower, any issues?

Other thoughts:

- Do your shower pipes or hot water cylinder run through the ceiling? Are they lagged?

- How close is the top of the shower to your ceiling?

Pure speculation, but I'm wondering if it is something like heat or vibration causing the initial issue - perhaps the gib isn't screwed tight to the ceiling, or there is a gap in the jointing tape - and IIRC, you've got that issue elsewhere in your house? Then once you've got an initial penetration in the paint, that spreads and causes your other issues. Just seems very unusual that it would bubble immediately after a first shower.

You can get a moisture meter from hardware stores, trademe, ebay etc. This Toolshed one looks okay (I haven't used it) and is on sale: https://www.thetoolshed.co.nz/product/20484-toolshed-digital-moisture-meter

If it is just steam, the best solution (IMHO) might be a shower dome or equivalent. Beauty is in the eye of the beholder, but they don't look great. But they are spectacular at limiting steam, and Mrs MDF really likes how much warmer they make the shower.

tweake

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#2930828 17-Jun-2022 10:03

networkn:

Where do I get a moisture tester from and how much would it cost?

It's worth noting we replaced the extractor fan after having the problem the first time.

was the gib ever replaced during all this?

if its not a moisture related issue, then i wonder if a solvent of some kind was used on the gib, soaked in and its slowly off gassing causing the pain to bubble. the only way to fix that would be to replace the gib.

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