Bulges in Exerior Siding

Noticed 5 areas on one side of the house that were bulging through the siding, all at the same level. I felt underneath one of the bulges and felt something solid underneath the wall sheathing. This was a pier and beam concrete foundation with rim joists and cross joists built on top. These bulges were at the base of the structural wall above the rim joists (it appeared the bottom of the wall studs were kicking out). There was no access to the crawlspace and visual access was limited from the crawlspace vents. In the picture you can see the shadow underneath the siding (below the arrow) where the wall was protruding. Does anyone have any ideas what this may be?bulges

What did it look like underneath the bulges?

It almost looks like the siding was not hooked/snapped together except that there are two bulges, one on top and right next to the one below it. And they usually come 2 to a piece of length of siding.

Fiber cement board siding. Just felt something solid poking through the wall sheathing at multiple locations at the same level near the bottom of the wall studs.

What did it look like underneath the bulges?

Anything kicked out on the inside?
Looks like the lap siding was nailed and the force still pushed it out.
Any of the piers kicked in underneath?

Felt underneath the siding and Could feel Something solid causing the wall sheathing to protrude. I wouldn’t have been able to see anything from inside the crawlspace anyways because the floor sheathing would have obstructed my view.

Concrete pier and beam with rim joists on top around the perimeter and joists framed out in the middle. The framed walls were installed on top of this and the bulging was at the same level with the bottom of the wall studs. Didn’t see any foundation distress from my limited view through the vents

Is it possible that it is just the plywood or OSB sheathing that bulged out, usually the bottom of the sheathing is typically at floor level. If there is no evidence of movement on the inside of the wall, it would most likely have to do with the sheathing that swelled and improper nailing.
Of course I am only speculating like others.

It could be anything. Any WAG is just that, a WAG.

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There’s really no way to diagnose this remotely based on the picture provided. I would suspect either a framing issue or sheathing problem though.

Fiber cement siding telegraphs all framing/sheathing irregularities. Wavy or out of plane wall could cause that.

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it almost looks like the wall plate is out further than the rim joist some kind of cantilever

I see discoloration of the siding adjacent to the electrical box (maybe)?
From here, I would call is water intrusion damage.

There are a lot of things a HI can do to gather additional associated issues to make an educated guess.
If you don’t want to do these, just call out detached siding…

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