Buckled torn vinyl siding due to building movement (C) Daniel Friedman Causes of Vinyl Siding Buckled, Rippled, Bent, Loose

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Causes of vinyl siding damage: buckled, rippled, bent, deformed, loose, or un-clipped: why does some vinyl siding take on an ugly look with ripples, bends, bulges, or even loose ends?

Beginning here in an article series on vinyl siding buckling we discuss all of the know causes of this defect. Watch out: rippled or loose vinyl siding may be more than just a cosmetic worry, and may indicate structural defects, building movement, leaks, or even heat or fire hazards.

Our page top photo shows wrinkled vinyl siding - often caused by heat exposure but in this case the extent, location, pattern and size of the damage made us suspect that there was another cause, as we explain below.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Causes & Cures for Damaged Vinyl Siding: Bent, Buckled, Rippled or Sagging Vinyl Siding

Rippled buckled vinyl siding (C) InspectApedia JBSurface distortion of vinyl siding has been recognized as a problem since the early 1960's when it was described as "oil canning" (Summers 1983). Beginning here we catalog all of the causes of and steps to cure or prevent buckled, warped, oil-canned vinyl siding as well as other forms of vinyl siding damage.

[Click to enlarge any image]

Article Series Contents

How To Sort Out the Causes of Rippled, Bent, Buckled Vinyl Siding: Product Defects, Sunlight, Heat, Installation Errors, other Causes

Reader Question: what is the probable cause of the buckled, rippled, loose vinyl siding in these photos?

Rippled damaged vinyl siding (C) InspectAPedia JB

First of all I would like to commend you on an excellent web site. I have considered it a valuable resource in my field of investigative engineering.

[Photos courtesy J.B. Click any image to see an enlarged, detailed version]

I was recently on your website viewing your information about vinyl siding damage and defects. I had an investigation just yesterday where I saw warped or rippled siding at a north side wall. This is a non-weathered side in Tacoma, Washington.

There is about 5’ of space between the wall and the property line fence and no utilities, etc. at that wall. There is a main floor living room and an upper floor master bedroom and that is all.

I have included some pictures for you that you may want to share on your web site and possibly comment on. There was no visible physical damage and no evidence of any water intrusion. At the worst areas the vinyl siding was pulled away from the wall and there was no staining or streaking over the building paper nor was there any bubbling of the paper or damage to the OSB sheathing found.

Trapped moisture between the siding and building paper due to late fall-early spring damp weather and low temperatures is the only thing that seems reasonable at this time, except for the possibility of material defect, but I am not aware of any such defects matching the conditions seen. The residence was built in 2005. Thanks, - J.B. P.E., Auburn WA

Reply: probably defective vinyl siding product; list of other siding buckling rippling bending diagnostic questions

Without a confident diagnosis of the cause of these vinyl siding anomalies I'm reluctant to rule out anything yet, but moisture as a root cause of rippling/buckling would surprise me; I think that plastics buckle and bend more in response to heat and physical stress, or sunlight and photo oxidation than to moisture exposure.

If I had to make a guess before we know more, I'd guess a defective product, thin and poorly formulated;

We might see product defects showing up inconsistently on different building walls for several reasons: exposure differences, installation differences, even different boxes or batches of product at the jobsite.

Since it would be odd for a quantity of defective siding to precisely match the square feet of a single building side or wall, I'd expect to find either some un-damaged siding (different product) on the mostly-damaged building wall, or some damaged siding (defective product) in some areas on other walls.

According to our siding contractor Eric Galow and somewhat supported by my own field inspections, some vinyl siding may be both buckled horizontally and rippled across the vertical width of segments because of what seems to be an inferior product formulation.

Twenty or more years ago there were (and there might be today) some lots of thin, poorly-formulated vinyl siding that warped and bent when exposed to intense sunlight or other heat sources, deforming worse than some of the more special cases we have already documented in our article series at VINYL SIDING INSPECTION & REPAIR

Vinyl siding defective product ? (C) InspectApedia JB

The siding in your photos seems to me to suffer multiple problems:

Although you have not yet seen water damage, leaks can be a bit subtle and even hidden unless the siding is removed entirely.

So it may remain possible that this condition is more than a cosmetic defect; loose siding risks leaks into the wall structure, inviting rot, insect damage, possibly even mold contamination; and the risk of wind blow-off of siding areas is of course much increased.

Siding Damage Diagnostic Questions?

Loose buckled vinyl siding diagnosis (C) InspectAPedia JB

As a technical aside, and certainly not having to do with the root cause of this badly rippled, loose, buckling vinyl siding, in the photo at left (click to enlarge) I see what looks like "more clean" vertical sections of wall siding in the upper right quadrant of the picture. There may be an insulation void or other interesting building condition going on there.

It would be diagnostic in confirming that the root cause of this siding damage is defective product if we could rule out other factors; Can you tell me

Other useful diagnostics for this siding buckling, rippling, and loose ends all found in one place would include:

Figure 1-23: Vinyl siding nailing guidelines (C) Wiley and Sons, S Bliss

Reader Follow-Up:

Thanks! My opinion is that it may likely be indirect heat reflecting from an upper floor window of their neighbor’s house which faces the damaged siding.  The siding damage is between the upper floor and stops about 5’ above ground so it is at a specific location.  The somewhat widespread uniform warping would seem to indicate it is not a material defect.

If I get permission to check the manufacturer I will let you know.   Thanks for your input and I agree that we all learn from each other’s collective experience, etc. - J.B.


Very interesting; I must have missed that option in our correspondence. There is no doubt that reflected heat from sunlight can cause rippled damaged vinyl siding - as I show at the page top photo


at VINYL SIDING DEFORMATION) (which you may have already seen) It would be useful to

Nice going.

Buckled Vinyl Siding due to Thermal Expansion & Improper Nailing

Vinyl Siding buckling & loose (C) Daniel Friedman

Vinyl siding will buckle due to thermal expansion if it is not properly installed. Properly installed vinyl siding here means proper placement of siding nails, not over-nailing too tightly, and allowing proper end clearance at single-piece siding runs to allow for thermal expansion. Vinyl siding that buckles due to improper nailing (photo shown above) is is not normally extremely wrinkled, and will be more wavy across longer horizontal runs of surface

And of course, more severe buckling vinyl siding will be found on a building sides more exposed to sunlight.

Experienced vinyl siding installers who want to avoid siding blow-off (see VINYL SIDING INSPECTION & REPAIR) refer to "hanging vinyl siding" on the building wall rather than "nailing vinyl siding to the building wall" precisely to remind workers not to nail siding so tightly that it buckles when heated.

On a wall section long enough to have spliced sections of vinyl wall siding in a given siding course, if we see vinyl wall siding that is buckled, we also check to see if the siding moves freely left and right on the wall.

It's easy to either use the butt of your hand to try to slide a siding panel left or right - it should move about 1/2" or so. If the siding feels tight we may check further by grasping the end or edge of a siding section to see if we can pull or push it.

When locking the vinyl siding panels into position, do not force them up or pull them down to adjust the alignment.

Too tight panels can tear and too-loose panels can unlock and come loose. One exception is at the band joint between the first and second floor where panels may come unlocked due to shrinkage of the framing. To compensate for this, some contractors pull the panels a little tight over the band joist area.

Range of Temperature Exposure of Vinyl Siding

At THERMAL EXPANSION of MATERIALS where we discuss the coefficient of linear expansion of many materials we note that vinyl siding can expand significantly along its longer length in response to temperature variations. Consider the vinyl siding installation shown in-process just below.

Vinyl siding installation at very low temperatures in Two Harbors MN (C) Daniel Friedman 2016

A crew of four workers was installing vinyl siding on this home in Two Harbors Minnesota in late February, 2016. The workers noted that when they started hanging siding early in the morning the outdoor temperatures were close to 0 °F and there was a biting wind to boot.

Considering that on a hot summer day the temperature on the surface of sun-exposed sides of this home may easily reach 100 °F the siding is exposed to temperature swings of 100 °F or more! Unless the siding is properly hung on the building, buckling of this material in hot weather would be no surprise.

Detailed specifications for hanging vinyl siding to avoid buckling and blow-offs are found in our article VINYL SIDING INSTALLATION - see:

Coefficient of Linear Expansion of Vinyl Siding

Buckled siding, possibly PVC or other plastic (C) anonymous reader

Above: badly-buckled siding on a building, photo provided by an reader. We're not sure what this siding material is: possibly plastic or pvc. I suspect this siding was installed without proper spacing allowance for thermal expansion.

Special thanks to Bob Fankhauser <>, a retired engineer / professional handyman and Habitat for Humanity volunteer who offered comments, suggestions, additions for vinyl CLTE (Coefficient of Linear Thermal Expansion), CPVC, PVC, cellular PVC, and vinyl (25 Feb 20-16) as well as helpful discussion concerning the wide variation in coefficients of expansion of materials given by various sources.

See the examples quoted at note 1 below.

1. PVC has a glass transition temperature (Tg) of about 165 F, and a coefficient of thermal expansion (CLTE) of about 3.5x10,-5,". - source: Stucky, David J., Randall M. Elinski, and Lori M. Hesslau. "System, method and apparatus for dark-colored siding panel product." U.S. Patent 9,145,690, issued September 29, 2015.

Vinyl Siding buckling & loose (C) Daniel Friedman

2. Vinyl siding has a high Coefficient of Linear Thermal Expansion (CLTE) as discussed in some of the citations given just below. For this reason siding manufacturers include long nailing holes and instructions to hang (loosely) rather than "nail" (tightly) vinyl siding to the building and to provide both overlap between siding sections and end or butt-joint clearances.

Vinyl Siding Deformation Reflected Sunlight & Heat from Nearby Surfaces,

This topic has gotten fat - we moved it's tubby self over to it's own room


Buckled Rippled Vinyl Siding Caused by Combined Factors: Heat + Nailing ?

Continuing the case of vinyl siding deformed by sunlight or reflected sunlight, siding that's rippled and damaged perhaps by a combination of factors is discussed


Buckled or Sagged or Rippled Vinyl Siding due to Point-Source Heat Damage - Barbecue Grill or or Heat Source

Please see the new home for grillers who cook their siding: VINYL SIDING GRILL COOKER DAMAGE

Fire-Damaged Vinyl Siding Photos

This hot topic got a page of its own, now atVINYL SIDING FIRE DAMAGED

Vinyl Siding Buckled, Torn Due to Building Movement

This topic has been moved to VINYL SIDING MOVEMENT DAMAGE where serious structural damage is suggested.


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