PLUMB LEVEL SQUARE

PLUMB, LEVEL, SQUARE

OR

“WHY YOU KEEP FAILING YOUR WINDOW TEST”

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It’s probably one of the first things any tradesperson learns after how to read a tape measure. The importance of “straight and true” was pounded into my head and I passed that down the line to my kids. It’s the basis of layout, accurate measurement and critical when setting windows and doors. When we investigate failures the first thing, we do is check plumb and level and look for the telltale signs of a sash not being squared to the frame. In fact the first time I showed my boys how to “shim” a glass door leaf off the glass, they were certain I was crazy and would break the glass. “who sticks a small prybar between the glass and frame to force setting blocks in between?”.? ?I have on occasion gone into our shop and told “installers” - it isn’t leaking because the gaskets or hardware are wrong, its leaking because the center-seal isn’t making proper contact due to the sash not being squared up. They usually think I am an idiot and keep going for a few days before they try what the idiot recommends.

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So, its easy to understand why people think testing huge specimen in a test buck on a wall is reasonable, after all it’s in a steel or heavy wood frame and best if all its CHEAP!!!!

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Maybe

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Maybe not

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Remember what I said about plumb, square and level? How important it is for windows and doors to operate correctly?

Well, it’s not just about a sash or door leaf opening and closing smoothly its also about air and water performance.

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Modern systems are engineered to be fabricated and installed at very tight tolerances. 20 years ago, a typical North American window system relied solely on gravity to drain water and we weren’t that concerned about small amounts of air leakage. Fast Forward to the present and it’s a different ballgame. You will be hard pressed today to find systems that don’t use European style hardware or a European designed system. That German high-performance window was designed for maximum efficiency and performance and was intended to be built by people in lab coats using state of the art CNC equipment. Then it comes time to test it and you send it to a lab who installs a unit that’s about 5’ x 8’ in a substantial wood “buck” and they put it on a test wall for different tests. Most times when a manufacturer is doing this, they have pre-tested the window so it usually passes the first time and everyone is happy.

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What about job specific tests and full-size mockups?

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They are not usually pre-tested and are almost always a custom design or combination of different parts that new. So you will likely be finding issues and will have to make modifications, sometimes many, before you pass. Now look at the photo above, keeping the plumb, level and square in mind. Do you think that frame and window will be picked up moved a few times and stay plumb and square? If you think you will just tweak it once it’s on the wall, guess again and every time its tested and failed, you pay and pay and pay. We believe that this is happening all the time, and it’s not the product that failing it’s the way it may be the way it is being tested that’s causing the failure! I saw this again and again during my years at the lab, it seemed to get much worse over the past 10-12 years because of all the new designs and increased demand for larger, project specific tests. People looked for the cheapest alternative to a full-scale mockup and offered a window tested to the job size and spec’s but in a test buck, not the job specific wall.

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When I started my own lab 9 years ago, I made solving this problem a priority. How could we do the job specific testing without building a huge and expensive steel structure – testing on a wall as described above was not an option. Cost is a concern and we looked for a solution which would tick off a few boxes:

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1.???? Eliminate problems caused by moving the buck (going out of square or getting damaged).

2.???? Allow for the window to be installed with all installation accessories.

3.???? Simulate job substrate conditions – whenever possible duplicate the wall or structure being used on the job.

4.???? Decrease chamber fabrication time.

5.???? Supply a “walk-in” chamber so witness’ can see the tests up close, technicians can make modifications all without moving the specimen.

6.???? Allow for a true structural evaluation with the job specific conditions and WITHOUT the test wall preventing deflection under load.

It needed to do all this and be priced competitively.

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Our solution was re-usable chambers and chamber walls. We achieve this with a permanent back wall, usually made from reinforced CMU and simple to construct side walls. The chamber front wall is built by the project carpenter or mason (though we can build them to job spec’s) and each trade performs the work they will do for the job, on the mockup; water proofer, windows, roofing – they all do the part the have on the job. ?This allows the project team to take advantage of one of the main benefits of a true job specific mockup at a fraction of the cost – coordination of the trades. We tell people that this is just as important as the performance tests. No matter how good the bim model, how thorough the descope, you don’t know for sure until you start putting it up in. ?

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Here are a couple we did recently

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For about the same cost as the problematic “buck on the test wall” we can do these simple chambers, they can accommodate very high test pressures and we can do the full array of tests on the window – you get the advantage of installing plumb, square and level and never needing to worry about that again.