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Window Water Resistance

Window Water Resistance

New postby Jack Wingo on Tue Oct 24, 2017 5:49 pm

Newly constructed 3 story house had water penetration due to faulty sealed windows. Builder is in denial stating it is normal for windows to leak during high winds. We had at the most 100 mph gust, which produces 26.07 psf pressure. What is the minimum requirement for window water resistance?
Thanks
Jack
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Re: Window Water Resistance

New postby Jerry Peck - Codeman on Tue Oct 24, 2017 6:24 pm

Jack Wingo wrote:Newly constructed 3 story house had water penetration due to faulty sealed windows. Builder is in denial stating it is normal for windows to leak during high winds. We had at the most 100 mph gust, which produces 26.07 psf pressure. What is the minimum requirement for window water resistance?
Thanks
Jack


Windows are only tested at a fraction of their design pressure.

Define the water penetration/leak - i.e., did the water 'get past the glass but puddled up on the horizontal window parts', or did the water 'get past the glass, puddle up on the horizontal window parts, and overflowed the edge of the horizontal window parts and drip off'?

My reference to "horizontal window parts" means mulls, meeting rail, bottom sill, etc.

Or, did the water get in 'around the window', which is not a "window issue", it is a "flashing issue".

Another thing which needs to be known is the design pressure of the windows, was the design pressure of the windows greater than that 26 psf?
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Re: Window Water Resistance

New postby Jack Wingo on Wed Oct 25, 2017 8:57 pm

Jerry
Not sure you received my reply, will post again.
I did not see house until a week or so after the storm. The client provided pictures that showed water and water damage on window sills and on wall and floor beneath windows. Afterwards, the builder added sealant between glass and window rails and mulls. So I'm guessing the windows failed rather than improper installation. I'm trying to obtain pressure rating. Are windows required to meet a minimum rating?
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Re: Window Water Resistance

New postby Jerry Peck - Codeman on Wed Oct 25, 2017 10:30 pm

Jack Wingo wrote:I'm trying to obtain pressure rating. Are windows required to meet a minimum rating?


Jack,

The answer is yes and no-not necessarily.

Yes, the 2014 FBC-Residential states: (underlining is mine)
- R703.1.1 Water resistance.
- - The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior veneer as required by Section R703.2 and a means of draining to the exterior water that enters the assembly. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section R702.7 of this code.
- - - Exceptions:
- - - - 1. A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapter 6 and flashed according to Section R703.7 or R703.8.
- - - - 2. Compliance with the requirements for a means of drainage, and the requirements of Sections R703.2 and R703.8, shall not be required for an exterior wall envelope that has been demonstrated to resist wind-driven rain through testing of the exterior wall envelope, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E 331 under the following conditions:
- - - - - 2.1. Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface and one wall sill. All tested openings and penetrations shall be representative of the intended end-use configuration.
- - - - - 2.2. Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size.
- - - - - 2.3. Exterior wall assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (299 Pa).
- - - - - 2.4. Exterior wall envelope assemblies shall be subjected to the minimum test exposure for a minimum of 2 hours.
- - The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings penetration or intersections of terminations with dissimilar materials.

That is the "yes" part.

Here is the "no-not necessarily" part: (from ASTM E-331 I have attached, this is not the current standard, it is the one I have on my computer, however, my recollection is that the critical aspects have not changed much to the current standard)

From the 2014 FBC-Residential: (underlining is mine)
- CHAPTER 46
- - REFERENCED STANDARDS
- - - ASTM, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428
- - - - E 331—00 (2009)
- - - - - Test Method for Water Penetration of Exterior Windows, Skylights, Doors and Curtain Walls by Uniform Static Air Pressure Difference
- - - - - - Referenced in code section number R703.1.1

(see attached file)
E331 Test Method of Water Penetration for Exterior Windows Skylights Doors Curtain Walls-Uniform Static Air Pressure Difference.pdf


From page 3, section 10: (underlining is mine)
- 10. Information Required
- - 10.1 The test-pressure difference or differences at which water penetration is to be determined, unless otherwise specified, shall be 137 Pa (2.86 lbf/ft2).
- - 10.2 Unless otherwise specified, failure criteria of this test method shall be defined as water penetration in accordance with 3.2.3. Failure also occurs whenever water penetrates through the perimeter frame of the test specimen. Water contained within drained flashing, gutters, and sills is not considered failure.

From page 1, section 3: (underlining is mine)
- 3. Terminology
- - 3.1 Definitions—For definitions of general terms relating to building construction used in this test method, see Terminology E 631.
- - 3.2.3 water penetration, n—penetration of water beyond a plane parallel to the glazing (the vertical plane) intersecting the innermost projection of the test specimen, not including interior trim and hardware, under the specified conditions of air pressure difference across the specimen. For products with non-planer glazing surfaces (domes, vaults, pyramids, etc.) the plane defining water penetration is the plane defined by the innermost edges of the unit frame.

An example of what the general public considers as leakage - water getting past the glazing.

An example of what the ASTM test standard considers as leakage - water overflowing the innermost projection edge of the frame. That means water can accumulate on the sill and other horizontal members of the window, such as the meeting rail, etc.

While I recognize you are only working on the information you have been given, your description does not provide enough information to assess 'what' allowed the water to penetrate from the outdoors to the inside.

Did the windows "leak" - depends on who you ask and what they define to be a "leak".

Did water penetrate through the windows sufficient to be defective - the only way to determine that answer is to do a ASTM E-331 water test on the windows ... but the contractor has already voided such a test as being able to produce a viable test result because the contrator "tampered with the evidence" by doing what you describe they did. If ... IF ... if an ASTM E-331 test is done and water actually does penetrate in sufficiently to create a "fail" condition ... the window manufacturer can claim that the contractor 'caused the failure' ... which would not matter to your case as the window would need to be replaced anyway, the only difference would be that the contractor would pay for it instead of the manufacturer ... HOWEVER ... if ... IF ... if an ASTM E-331 test is done and the window does not "fail" - what the contractor did makes that "not a pass", just an "invalid result" because the contractor tampered with the evidence and altered the window from how it was manufactured ... end result is that the window would need to be replaced anyway and then test the replacement window after it is installed ... with no one tampering with the window.

How many windows are involved? What would the cost be to replace all the affected windows? There is no guarantee that the contractor or the window manufacturer will be found at fault, meaning that the owner may have to pay more for attorney's fees and expert's fees than the cost of replacing the windows ... or the owner may get everything covered and not pay for any of it ... that is a factor the owner needs to consider. Some owners have enough money to not worry about cost, they can afford to "make a point", other owners need to consider the costs involved.

You did notice where the ASTM E-331 test is done at "137 Pa (2.86 lbf/ft2)" ... 2.86 psf ... not 26 psf ... windows are tested at much lower pressures than the design is for. If the window does not "fail" at 2.86 psf - do you think that is assurance that the window will not "fail" at 26 psf?

Which gets the entire concept back to "codes are MINIMUMS", not what 'should' be designed and installed.

Do windows leak and let water in? Is that a "code" violation? Or is that a violation of "merchantability" of the product (the house)?
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