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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.
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?
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
The siding in your photos seems to me to suffer multiple problems:
it is rippled across the width of the "board" segments (a heat and formulation problem most likely), and
ends have come loose and curled
the clip-on bottom edge of the siding segments failed to remain clipped in position.
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?
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
The age of the building (2005 in this case, or about 8 years old). Eric Galow notes that following Hurricane Katrina (also 2005) not only were many common building products in short supply, but the price of building products using petroleum products increased significantly. We also SPECULATE that around the same time there may have been batches of hastily-produced and defective building products including siding and roofing materials.
The estimated age of the siding (2005 in this case) - and can we assume that this is the original siding? Probably.
Where the siding was purchased and thus tracing back through that supplier, who made it.
Siding thickness and chemical properties: siding age, manufacture, brand name, model, any markings on reverse side, and actual siding thickness can explain product failures. We have noticed particular generations or batches of vinyl siding prone to cracking, breakage, color fading, and surface chalking as the vinyl siding weathered;
The geographic location & climate where the building is located
The temperature and weather conditions when the siding was installed, and the temperature and weather conditions when the buckling vinyl siding is most-evident.
Other useful diagnostics for this siding buckling, rippling, and loose ends all found in one place would include:
Is the siding equally damaged on all sides of the building or is the problem worse only on one particular side - the North side per your original note? You indicate that damage is just on one side, the North face - confirmed by your photos and emphasized by the presence of some algae on the siding surfaces. Since North is not the sunny side for buildings in North America, what other site conditions are different for this building side?
Examples might be different product installed, reflected heat from another nearby building wall or glazing, chemical exposure, prevailing wind, even simply different installation practices by an individual worker or team from those installing siding on other building walls.
Is the siding nailed too tightly (it should be hung, not nailed tightly, and we should be able to slide segments horizontally 1/2" or more)
(See Thermal Movement in Vinyl-Sided Walls and
What is the thickness and condition of the building sheathing to which siding is nailed? Did nails simply pull out? This would not explain siding buckling, or rippling but can contribute to loose flapping siding or siding ends at butt joints.
Was the siding placed properly when it was nailed in the first place? If the siding was pushed upwards too tightly, clamping very tight on the connecting lip of each siding segment below it might have encouraged stretching then warping and loosening due to subsequent heating;
Housewrap: Regarding "nor was there any bubbling of the paper" - was conventional housewrap installed behind the siding or some other building paper or nothing? Housewrap won't explain rippled buckled siding but relates to moisture control and building leaks.
Was this siding ever removed and re-installed on the structure? (look for old nail holes, nailing flange damage, etc)
Siding performance compared with other siding installations in the same area, of similar age, same contractor: Are there other buildings constructed in the same area, at the same time, or by the same contractor whose siding shows similar damage? This can point to a more extensive use of defective product, or in some cases the same siding installation crew making the same installation errors on multiple buildings.
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.
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 INSPECTION & REPAIR and in discussion in this article (below
photo document the site, the relationship of the building wall and opposing windows, and
to measure the distance between the surfaces and to
project the pattern of reflected heat from opposing windows on an adjacent building to see if the siding buckling or rippling maps those areas
If you've got an IR or other thermal scanner you could also make some interesting measurements in and out of the reflected heat areas on the receiving building wall.
In the case of window-reflected heat I've already documented, the distances were short, there was some protection from wind and air movement, and ultimately we could practically "see" the pattern of damaged vinyl siding matching exactly the parallelogram of a distorted window shape effected by the angles involved.
Buckled Vinyl Siding due to Thermal Expansion & Improper Nailing
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
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.
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:
Special thanks to Bob Fankhauser <firstname.lastname@example.org>, 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.
PVC, cellular, 4.5 x 10-5 in/in/F" for rigid PVC & "3.2 x 10-5 in/in/F - source: "Versatex Trimboard", http://versatex.com/PDF/D-1_Physical_Properties.pdf (2016/02/24)
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.
Beck, David H., Robert D. Shaw, and David J. Stucky. "Temperature-expansion indicator for siding panels." U.S. Patent 6,939,036, issued September 6, 2005.
Hendrickson, Gerald L., Kurt E. Heikkila, Timothy P. Murphy, and Maurice N. Goeser. "Fiber-polymeric composite siding unit and method of manufacture." U.S. Patent 6,122,877, issued September 26, 2000.
Kellis, Warren D., Daniel King, and Lyle Rice. "Plastic siding mounting system." U.S. Patent 4,669,238, issued June 2, 1987.
Kendall, James R., "Vinyl siding bracket." U.S. Patent 3,458,962, issued August 5, 1969.
Excerpt: Rigid vinyl and similar thermoplastic materials or even aluminum have a high coefficient of thermal expansion, relative to conventional building materials, such as wood, steel and the like. For example, in warm climates during the summer months, sidings can easily reach an extreme temperature of 120 F., and it is not at all uncommon for siding to be installed during a winter at temperatures of 20 F. or even below. Where such extreme temperatures are involved, a temperature differential of at least 100 can very definitely occur, and in the case of a foot vinyl siding, a thermal expansion and contraction of at least one-half inch would occur.
Mowery, Jack T., and Benjamin L. McGarry. "Splicing member for siding panels." U.S. Patent 6,393,792, issued May 28, 2002.
Excerpts: Another problem encountered in the installation of siding panels is their rate of expansion and contraction. Vinyl siding panels have a relatively high thermal coefficient of expansion, on the order of 4.5×10 −5. Therefore, for a typical 12′ long panel, there can be a variance in its length of up to ¾″.
Patterson, John, and Gene Szamborski. "Expanding PVC as a building material." Journal of Vinyl and Additive Technology 1, no. 3 (1995): 148-154.
Rabinovitch, Elvira B., and James W. Summers. "The effect of physical aging on properties of rigid polyvinyl chloride." Journal of Vinyl Technology 14, no. 3 (1992): 126-130.
Rabinovitch, Elvira B., and James W. Summers. "Weather resistant plastic composites capped with polyethylene terephthalate glycol (PETG) for outdoor exposures." U.S. Patent 6,855,402, issued February 15, 2005.
Stucky, David J., Robert D. Shaw, and Stephen W. Steffes. "Siding panel tab and slot joint." U.S. Patent 7,207,145, issued April 24, 2007.
Summers, James W. "Formulations for vinyl house siding: History, present, future." Journal of Vinyl Technology 5, no. 2 (1983): 43-46.
This article notes that plasticisers added to improve vinyl siding impact resistance also increase its coefficient of expansion.
Vinyl Siding Deformation Reflected Sunlight & Heat from Nearby Surfaces,
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Bob Fankhauser <email@example.com>, 503 206 9824 Cell, 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.
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: firstname.lastname@example.org or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions. [ About Hurricane Katrina and building products, personal communication, 8/27/2013]
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