Fiber cement siding and room ceiling

BAGW:

On the siding there's water vapor trapped behind the paint. The bulges are from the water vapor pushing outward. When the sun warms the surface the rise in temperature dives the moisture back into the cladding material. The sagging of the drywall could be a variety of things. 1/2" gyp board fastened to joists/trusses that are 24" on center will sag. This would be made worse by high moisture levels in the house. What's the relative humidity level?

Regards,

DB

Thank you. Looks like both are common issues and more of aesthetic..

1) how do I fix the water vapor getting trapped in the paint? Do I need to get the cladding repainted? Or just leave it the way it is

2) the relative humidity of the house is set to 20%.. do I need to go higher.. the temp here is close to zero.. this gyp board sagging is in one room only at one location.. how does relative humidity impact the sagging of the gyp board? How do I fix this? Can this sagging happen over the age of the house? What are the other issues that may cause the sagging?

It almost looks like the clouded region is touching the flashing. If so, you could start by trying to get a small gap so the siding does not absorb the rainwater that inevitably pools at the intersection between the two. Next time this happens press on the bulges and I bet the paint will flex back and forth. Was your home painted on site, or was that a standard hardie panel color? If in the field, the area could have been too wet when it was painted. I have some regions of my hardie board that has some small paint adhesion problems. Re-painting will be the repair.

Drywall is imperfect and lighting like in the picture will show problems in almost any ceiling. That was one reason the old stipple finish was used for ceilings. How much is the sag?

The house is 2004 built and I am not the original owner.. cannot say when the paint was done..

Sag might be 1/8” or less.. I can’t see it now.. have to wait for night so that I can use the lighting in the pic to see the sag.

BAGW:

1) For the long term health of the structure you need to find out the source of that water. Is it wind blown rain hitting the wall and getting behind the cladding? Is there a high humidity source on the opposite side of that wall like a laundry or shower? Is there some insulation missing at that location? Is there a vapor barrier present in the wall, and where is it located in the wall assembly? An RH of 20% is pretty low so I don't think its simply house moisture. It appears that the bubbles only occur in the bottom course of siding and that course is sitting on a flashing strip. My guess is that water is getting behind the siding running down the wall and then being trapped at the flashing instead of exiting to the outside. If you could remove that course of siding and perhaps raise it 1/4" and install shims to kick that bottom course out just a bit then the water could easily exit. The first step is to find the source of the water.

If you want to get a better understanding of moisture movement in walls you might want to look at the Building Science Corp website. There are numerous articles posted there dealing with problems similar to yours.

2) As I mentioned 20% RH is pretty low so the sag is probably just a function of the strength of 1/2" gyp board. Options are to remove and replace with 5/8" board or simply laminate the 5/8" board over the existing ceiling. As Brad mentioned, a change in the lighting might be the easiest and cheapest solution. My guess is that it won't get any worse.

Regards

DB

I don't think the ceiling drywall sag is necessarily the concern of BAGW now that I look closer. There are 4 arrows on that picture pointing to localized bubbles. Those to me also look like some form of moisture damage. Maybe there's a joint in the ceiling vapour barrier there that is leaking. You may be able to see what the issue is by going into the attic and getting a look at the topside of the drywall in those locations.

There is no attic on top.. there’s a bed room. I doubt if it’s a water damage

They could be nail/screw pops I guess, but normally they don't look that large. Those appear to be roughly 6" diameter?

I too think those are nail pops. Stand on a chair and press with your fingers. Pops will flex.

If you press on the drooping/bulging paint, be prepared for a sudden deluge of water.

Jim

I pressed on the drops.. it dint even flex.. sag might be just from the age of the house as the glue might have come off

Yeah are pretty big for nail pops.. looks like sagging between the nail attachment as someone mentioned in the above thread

Thanks all

On the ceiling - non structural issue. Proper plasterboard fixings weren’t used and now they’re popping. Happened all over my own house. Pick the loose bits off and fill with Polyfilla (or whatever the equivalent is there). Or just leave it. I did for years!

The boarding definitely has moisture trapped behind the paint. I’d love to stick a pin in it when its bulging!

Many contractors still prefer to use nails to fasten drywall to ceilings. In 2004 the options for screw guns was far less than it is now. I have been told many times about the time difference. I am not a fan of nails.