Help identifying issue for a client

Hello all! Have appreciated reading all of the helpful comments usually found on the forum.

I inspected a home with masonite/hardboard siding which had significant waves with no other indications of issues. Thinking that some of you migh have seen something similar and could enlighten me on possible causes. This is a home built in 1978 with a crawl space with minimal to no cracking in the foundation and minimal movement inside.

Thanks in advance for your input!

Rick Sheldahl

May be moisture from poor sealing?

Could be ghosting of sheathing or improper spacing of the siding.

Sheathing or siding issues JMO

Thanks Martin. My initial thought was moisture but there were no supporting findings. Siding was in good shape, no elevated moisture readings. Really has me confounded.


Is that a bathroom behind the single window where the rippling is the worst?

I have also seen this condition in houses from the 70’s that used this type of siding. I have seen it on the entire house bowed where every stud was. Other than the bowing the siding looked fine. I seem to recall a class action law suit about this a number a years back.

Was there a gap between butt joints?

Maybe one of these?

1 Like

Hey Aaron,

The gap did exist but was caulked as required for hardboard.


Thanks everyone for your feedback!

David, there is a bathroom behind that window.



Just looked at the lawsuit document. Letter “d” certainly seem to apply. Will have to see if they can identify the manufacture by removing a piece of siding that has the more traditional damage.


I can not be sure but, this looks like vinyl siding. If it was nailed too tight or if there is an adjacent structure that is this reflecting light on the surface, ripples will be seen.

Could there be a leaking fixture on that wall causing moisture issues??