# Painted Aluminum Siding Bubbling



## Gymschu (Dec 12, 2010)

Hard to say what's causing your issues. You basically did everything right although an OIL-based primer was not necessary. The only thing that might have happened is that the pressure washing pushed some water into and under the siding. That moisture could be causing an issue although it's a long shot guess. Or, since it happened after some rain, water could be getting in behind the siding some how.

What paint was used? Hopefully you used a quality latex paint from Sherwin-Williams or Benjamin Moore.


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## AllanHillier (May 21, 2015)

Thanks for the quick reply. I live in Nova Scotia Canada, I used Beauti-Tone paint from Home Hardware, the rest of the house is fine just ten rows on one side that are affected. I primed it because there were a few spots that were worn down to the aluminum and I read somewhere that latex paint contains ammonia and it will react with the aluminum and cause gases under the paint. I really thought this was my issue so that is why the primer. It doesn't need to be wet for the bubbling to happen it is just worse when damp or humid. I should see if I can upload some pics. New to this site so not that familiar with it yet.

Allan


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## Gymschu (Dec 12, 2010)

Definitely post some pics. Sometimes others can see issues that you may be overlooking.


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## AllanHillier (May 21, 2015)

I added 4 pictures in my album, not sure of any other way to post pictures. I'll get some more pics after a rainfall as well and post them.


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## Gymschu (Dec 12, 2010)

The pics definitely look like moisture is getting under the paint film. Aluminum has weep holes on the underside of the panels that allows any moisture behind the aluminum to escape. My best guess is that moisture is getting behind the siding from a faulty drip edge, gutter, etc. and finding its way through the weep holes causing the paint to bubble like that. Now you have to do some investigation to see how that moisture is getting behind the siding.
Again, I'm taking a shot in the dark. I've had this sort of thing happen on aluminum siding that I painted several years ago and discovered a faulty gutter situation that was allowing water to overflow BACKWARDS toward the house and making its way behind the siding causing blisters.


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## AllanHillier (May 21, 2015)

I suppose this is plausible. It doesn't explain why there is bubbling with no rain, I popped a bubble thinking I would see moisture but it was completely dry. I will inspect to see if there is any water intrusion anywhere I can see. The bubbling is only at the bottom of the house, the upper part has no issues. My house is a 2 story house.


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## carpdad (Oct 11, 2010)

These are just guesses.
1. Just bad spot from the factory paint, so sand the spot off to bare metal?.
2. ???-aluminum reaction to another metal behind the spot??? One bad nail? Ground wires? Cables?
3. Water gets trapped in the J part of the siding and does not allow the paint to bond. Don't throw water at it. Wash, wait a month and when ready to paint, just wipe the area with alcohol. Don't scrub with alcohol - it will remove water based paint.


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## ToolSeeker (Sep 19, 2012)

Here's my guess when it was painted there was a small amount of moisture in this area and it was painted over and the paint didn't bond so basically it is just laying loose on the surface. Another thing that could have affected the adhesion was the TSP if for some reason this area didn't get rinsed as well as the other areas it could have caused this problem (one of the bad reasons for using TSP, must be rinsed several times).

Aluminum siding unlike wood will not absorb moisture so if any got between the paint and the siding it will be there for a long time. After time with the sun and all these spots have gotten bigger.


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## Colbyt (Jan 27, 2014)

Toolseeker's guess is a good one.

My follow-up question; is it peeling where primed or not primed? 

I was told by my paint dealer to spot prime bare metal and then prime the entire job before painting. Going on 10 years and still looking good.


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## Oden (May 23, 2015)

Gymschu said:


> The pics definitely look like moisture is getting under the paint film. Aluminum has weep holes on the underside of the panels that allows any moisture behind the aluminum to escape. My best guess is that moisture is getting behind the siding from a faulty drip edge, gutter, etc. and finding its way through the weep holes causing the paint to bubble like that. Now you have to do some investigation to see how that moisture is getting behind the siding.
> Again, I'm taking a shot in the dark. I've had this sort of thing happen on aluminum siding that I painted several years ago and discovered a faulty gutter situation that was allowing water to overflow BACKWARDS toward the house and making its way behind the siding causing blisters.


For sure it is something along these lines. Could be as simple as a clogged downspout/gutter. If you love there it's a easy enuff check. Next time it rains. Pull out the umbrella go out and see what's going on. You could mimic the rain with a hose in nice weather, to a extent. But nothing beats the real thing.


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