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Vinyl Windows

skipharper

skipharper

REGISTERED
Joined
Dec 23, 2009
Messages
242
Location
Louisa County, Va.
Did you know that wood framed homes and vinyl windows don't mix? This is a quote from a structural engineer who recently assessed the damage to a home by the earthquake in Virginia last August: The two cracked window frames was caused by the differential movements between the vinyl windows and their wood framed openings due to the differing thermal expansion rates for wood and vinyl, and were not the result of the earthquake event. Feel free to elaborate!!
 
NICE!!!!....I had a vinyl siding rep tell me once the reason their siding warped was that the new windows reflected soooo much heat that it melted the siding.....It wasn't a bad install or siding product, NOPE, couldn't be....
 
steveray said:
NICE!!!!....I had a vinyl siding rep tell me once the reason their siding warped was that the new windows reflected soooo much heat that it melted the siding.....It wasn't a bad install or siding product, NOPE, couldn't be....
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The rep was correct. Happens a lot with the new windows that are made today.
 
WOW.....I guess the windows should come with a warning about installing them in a house with vinyl siding, or we go back to single pane glass.........the case I was involved in as an inspector was a job with no permits or inspections after the fact that a homeowner got taken on, so I assumed the worst of the contractor....

Still.....hopefully the industry has addressed this and made sure their products are compatible....
 
skipharper said:
Did you know that wood framed homes and vinyl windows don't mix? This is a quote from a structural engineer who recently assessed the damage to a home by the earthquake in Virginia last August: The two cracked window frames was caused by the differential movements between the vinyl windows and their wood framed openings due to the differing thermal expansion rates for wood and vinyl, and were not the result of the earthquake event. Feel free to elaborate!!
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Let me guess, the engineer worked for the insurance company.
 
This says the neighbors siding, not yours.

The National Association of Home Builders (NAHB) Report

The Effect of Reflected Sunlight from Low-e and other Double Paned Window Glass on Vinyl Siding

OVERVIEW

Glass in double paned windows may on occasion slightly warp or deflect due to a difference in

barometric pressure between the interior of the glass panes and the outside air pressure. This can

create a concavity in the glass. Such a concavity is a normal response to pressure differences, does not

affect the performance of the window, and does not constitute a defective window condition. However,

the concavity may focus sunlight reflected from the window in a fashion similar to the effect seen when

light passes through a magnifying glass. The heat generated by the focused reflected sunlight has proven

sufficient to visibly damage and distort vinyl siding on nearby houses. Any double paned window may

cause this effect, but double paned low-e windows have a higher reflectivity quotient which can

exacerbate the reflected light/vinyl distortion phenomenon.
 
Walt Disney Concert Hall in Los Angeles

After the construction, modifications were made to the Founders Room exterior; while most of the building's exterior was designed with stainless steel given a matte finish, the Founders Room and Children's Amphitheater were designed with highly polished mirror-like panels. The reflective qualities of the surface were amplified by the concave sections of the Founders Room walls. Some residents of the neighboring condominiums suffered glare caused by sunlight that was reflected off these surfaces and concentrated in a manner similar to a parabolic mirror. The resulting heat made some rooms of nearby condominiums unbearably warm, caused the air-conditioning costs of these residents to skyrocket and created hot spots on adjacent sidewalks of as much as 140 °F (60 °C).[citation needed] After complaints from neighboring buildings and residents, the owners asked Gehry Partners to come up with a solution. Their response was a computer analysis of the building's surfaces identifying the offending panels. In 2005 these were dulled by lightly sanding the panels to eliminate unwanted glare.

At the rate that the green building code is growing, vinyl will be outlawed soon.
 
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There's a common trend among professional engineers; their opinions vary just like everyone else's.

What reference did he use to support this conclusion?

Francis
 
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The Wood Handbook published by the U.S. Dept. of Agriculture Forest Products Laboratory says the coefficient of thermal expansion for wood ranges from 3 - 4.5 (x 10^-6) longitudinally, and 5 - 10 times greater across the grain. It also says "Even in the longitudinal (grain) direction, where dimensional change caused by moisture change is very small, such changes will still predominate over corresponding dimensional changes as a result of thermal expansion unless the wood is very dry initially."

http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr190/chapter_04.pdf

Aluminum has a coefficient of thermal expansion of 2, and PVC around 50.

I have never installed vinyl windows, but I know that vinyl siding has slots and shouldn't be nailed too tightly because it needs to be free to expand & contract. I wonder if the windows in question might have been attached too firmly and cracked before the earthquake, but nobody noticed the cracks until they looked for damage after the earthquake.
 
I wonder if the windows in question might have been attached too firmly and cracked before the earthquake,
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Or cracked during the earthquake.

A lot of windows are foamed in today and will make for a very rigid area betweeen the vinyl window frame and the wood framing.
 
Hotels have had hot spots around the courtyards that are the focal point of low e glazings. Sounds like a green opportunity, build the south wall in a parabolic shape and focus on the hot water heater in the yard, or the neighboras house that blocks your view.

Typically caulked fins as well.
 
The windows in question were installed per the manufacturers install instructions and inspected by our department. In talking with someone from the vinyl window organization the reason new windows are installed into the rough opening with 1/8-1/4 inch gap is for thermal expansion. The engineer does represent the insurance company and I know this because they are in my home!! The great part about this message board is the knowledge everyone brings to it. The vinyl siding information is true as someone provided a link to it. Something to be cautious about is when someone gets replacement windows and the installer leaves the existing frame and tight fits the new window--now the thermal expansion may create a problem.
 
The impact of thermal expansion is going to be minor relative to the impact of expansion due to changes in the moisture content of the wood.

I'd ask the engineer for calculations demonstrating thermal expansion was the cause.

Then I'd cash the check.
 
skipharper said:
The windows in question were installed per the manufacturers install instructions and inspected by our department. In talking with someone from the vinyl window organization the reason new windows are installed into the rough opening with 1/8-1/4 inch gap is for thermal expansion. The engineer does represent the insurance company and I know this because they are in my home!! The great part about this message board is the knowledge everyone brings to it. The vinyl siding information is true as someone provided a link to it. Something to be cautious about is when someone gets replacement windows and the installer leaves the existing frame and tight fits the new window--now the thermal expansion may create a problem.
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The engineer is full of somptin! Vinyl windows are very thermally active no doubt but if centered in the rough opening and provided with an expansion joint at the exterior they will do fine for many years.

About seven years ago I was busy replacing vinyl windows in the Tucson area. It was a warranty effort on behalf of the manufacturer. I insisted that the stucco subcontractor hold the stucco 3/8" away from the window frame so that I could install an expansion/sealant joint around the frame. One particularly obnoxious home owner complained that my installs looked different than the remainder of the windows on his home because of the expansion joint. He went so far as to complain to the Registrar of Contractors. When the inspector from the Registrar's office came out he initially sided with the home owner. I managed to get a few minutes with him alone and suggested that the many thousands of homes in Arizona that had stucco tight to the vinyl windows were an indication that the ROC wasn't really protecting the citizenry as they are charged to do. The inspector came around to my side and suggested that the home owner ask the builder to make the remaining windows resemble mine.

Bill
 
KZQuixote said:
The engineer is full of somptin! Vinyl windows are very thermally active no doubt but if centered in the rough opening and provided with an expansion joint at the exterior they will do fine for many years.About seven years ago I was busy replacing vinyl windows in the Tucson area. It was a warranty effort on behalf of the manufacturer. I insisted that the stucco subcontractor hold the stucco 3/8" away from the window frame so that I could install an expansion/sealant joint around the frame. One particularly obnoxious home owner complained that my installs looked different than the remainder of the windows on his home because of the expansion joint. He went so far as to complain to the Registrar of Contractors. When the inspector from the Registrar's office came out he initially sided with the home owner. I managed to get a few minutes with him alone and suggested that the many thousands of homes in Arizona that had stucco tight to the vinyl windows were an indication that the ROC wasn't really protecting the citizenry as they are charged to do. The inspector came around to my side and suggested that the home owner ask the builder to make the remaining windows resemble mine.

Bill
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That's one strange story. The stucco contractor, Shirley, remembers you. And guess what, they are still installing windows wrong in the thousands.
 
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ICE said:
That's one strange story. The stucco contractor, Shirley, remembers you. And guess what, they are still installing windows wrong in the thousands.
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The stucco contractor was my sub and is a friend of mine. And while builders in Arizona are still installing thousands of windows without expansion joints mine are free to move and will last years longer.

Bill
 
Kind of off topic but I had mentioned low e windows and heat reflection earlier in the thread. I've seen them buckle vinyl siding in the reflection area of a window. I was opening the windows over a porch roof yesterday and noticed the shingles had blistered. Went out on the roof to check and the main body of the roof was fine. I then lookesd closer and the damage was restricted to an area in front of 2 pairs of windows. The homeowner happened to have a little IR heat sensor and we checked the main body of the roof, 145-155*, nothing higher than 155*. The zone right in front of the windows was 175-185*. Ambient was about 75* We could open the windows and the temp of the shingles in front of the windows would start dropping.
 
DRP said:
Kind of off topic but I had mentioned low e windows and heat reflection earlier in the thread. I've seen them buckle vinyl siding in the reflection area of a window. I was opening the windows over a porch roof yesterday and noticed the shingles had blistered. Went out on the roof to check and the main body of the roof was fine. I then lookesd closer and the damage was restricted to an area in front of 2 pairs of windows. The homeowner happened to have a little IR heat sensor and we checked the main body of the roof, 145-155*, nothing higher than 155*. The zone right in front of the windows was 175-185*. Ambient was about 75* We could open the windows and the temp of the shingles in front of the windows would start dropping.
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Hey DRP,

There's no doubt that as windows are asked to reduce their solar heat gain coefficient, the heat has to go somewhere else. This has everything to do with glazing and nothing to do with window frame materials.

Bill
 
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