Wavy Siding

[Terry Beck]

1987 house with some sort of wood composition siding material. Siding is very wavy (warped, deformed) in many areas, most dramatic on South-facing side. The attached picture is actually the East side where I had the best light for my camera. It is not restricted to only upper or lower sections of the wall, is present around and between windows. Material is dry to touch and my moisture meter picks up nothing unusual. There is no movement when I press against it.

Inspection in attic of interior side of gable end wall reveals that there is no sheathing installed between the siding and the framing. When I feel along the bottom edge of the siding, it seems too thin to consist of both siding and sheathing. No visible evidence of house wrap (which is typically required).
I have seen some houses before where there is no sheathing above the top plate, but sheathing is installed below the ceiling level. It's hard to tell on this one, but I strongly suspect there is no sheathing anywhere. I also know that several siding manufactures recommend, but do NOT require sheathing.

One friend also suggested that the siding material might have gotten damp during construction, and warped after it was put up.

Any other ideas or explanations? To me it seems to be a good example of install on the cheap, certainly NOT preferred construction, but at this point in time it is mainly a cosmetic issue (i.e. no structure failure, house is sealed against the weather, etc.). I will suggest a contractor review, but essentially it is up to the buyer to decide if they want a less than perfect house (we have a LOT of those around here anyway).

[chris mcintyre]

Looks like hardboard siding to me, there is a lot of it in my area due to the fact there was a Georgia Pacific plant here. It came in 12" panels, best described as a double 6" German siding look and is very susceptible to moisture.
If that is what you have, I could see the lack of a WRB letting enough moisture from inside the house being enough to make the siding wavy.

[Matt Fellman]

If it looks that bad on the east side I can only imagine what it looks like in the sun. Unfortuantely even the good (I can't believe I even use this term) hardboard siding only gets about 25 years and that's where you're at.

Without seeing the rest I can't say for sure but it looks like you should be calling out failed siding as opposed to just "further evaluation".

[Jerry Peck]

Inspection in attic of interior side of gable end wall reveals that there is no sheathing installed between the siding and the framing. When I feel along the bottom edge of the siding, it seems too thin to consist of both siding and sheathing. No visible evidence of house wrap (which is typically required).
I have seen some houses before where there is no sheathing above the top plate, but sheathing is installed below the ceiling level. It's hard to tell on this one, but I strongly suspect there is no sheathing anywhere. I also know that several siding manufactures recommend, but do NOT require sheathing.


In many areas, sheathing was not, and is not, required, instead they use diagonal braces on the wall (such as metal straps installed on the face of the studs or wood bracing let-into the face of the stud). Also, many areas did not used to call for a WRB either, but they now do as the code now does. One of those 'common sense be damned, the code does not require it' things - which still go on, only with different things.

As the others have said above, recommend replacing it, not "further evaluation", that may only lead to some knucklehead saying that it is okay, your client selling in a couple of years and then they have to replace it for their buyer because their inspector said to replace it ... you do know who will get the call to write the check to replace the siding - you, because you did not call it out for replacement.

[Wayne Carlisle]

My thoughts;
The studs behind the siding were not placed per manufactuers recommended installation procedures. Probably 24" instead of 16" oc.

They used the "hidden" nail method, nailing the siding at the top and hoping that the bottom of the siding did not do what it did...wave.

It may be possible to nail the bottom and do away with some of the wave, but it looks like the wave is in-between the studs too. There may not be the proper spacing in-between the joints of the siding where it butts together.

Just my opinion.

[H.G. Watson, Sr.]

There have also been quite a few class-actions, etc. regarding compositon siding over the years, as well as bkrpcy's of companies, etc. Failures have been reported even when was installed per mfg's instructions (at the time materials were produced).