# If it's level and plumb, it must be square, right?

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• posted on November 12, 2009, 9:50 pm

Why do we check for square?
Let's say I'm installing a window. I put the window in the rough opening, shim it up and grab my level.
It's plumb on both sides, and the top and bottom are level.
How could it *not* be square?
For it to be out of square, at least 1 of the 4 readings I took with my level would be off.
If the window were racked, then the sides wouldn't be plumb.
If one side was longer than the other, then the top wouldn't be level.
If the bottom was longer than the top, then one of the sides wouldn't be plumb.
I can't think of a scenario where both sides are plumb and the top and bottom are level but the window isn't square.
What's the point in checking for square?
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• posted on November 12, 2009, 9:56 pm

Sanity and helps ensures don't have bad level or misread it or, or, or, ...
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• posted on November 12, 2009, 10:06 pm

It's the quickest way to check squareness. Your level could have a bad vial. Your eyeballs might not be square to the level in one position. There's no interpretation required. Lots of reasons.
R
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• posted on November 12, 2009, 10:12 pm

I had a hack put in windows and sliders, after I paid him it rained and they leaked and he wouldnt come back. I called the window co, Anderson, and they said a rep could come out. The first thing he did was check square on the slider and told me it was out of spec. He said they allow up to 1/8" out of plumb,level, or square and that I had no warranty and should have my windows reset that failed. I see your point on level, but the rep first checked square with a tape measure as that is a measurement that can be used to fail or pass a warranty. He said I would be suprised how many fail. After seeing my hack work I know many are installed wrong and have no warranty from day 1.
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• posted on November 12, 2009, 10:48 pm
On Thu, 12 Nov 2009 14:12:10 -0800 (PST), ransley

Some Andersen patio door frames are assembled on the floor at the job site. A " tape measure" check is made then for square. Trick is picking the frame up and not twist or not torque it, putting it into the RO.
Open a sash slightly - note the reveal between the frame and sash - top and bottom. How wide is that gap? If way off fix the window.
Hacks get paid by piece work.
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• posted on November 12, 2009, 10:59 pm

I first got worried when I saw his level was only about a foot long, then I got more worried when he worked like he was on crack as the windows flew into place, after it rained I knew I really screwed up since I had just paid him and I had alot of leaks.
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• posted on November 12, 2009, 11:32 pm
On Thu, 12 Nov 2009 14:59:27 -0800 (PST), ransley

I've mentioned here before that if a window/door installer without numerous levels arrives - send him packing.
I would put my own window in before I turned a hack loose with a "foot long" level :-//
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• posted on November 12, 2009, 11:46 pm
On Thu, 12 Nov 2009 14:59:27 -0800, ransley wrote:

At least they'll leak both ways, so once your house fills up you don't need to open the windows to let the water out again. Or something.
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• posted on November 12, 2009, 10:16 pm
On Thu, 12 Nov 2009 13:50:52 -0800 (PST), DerbyDad03

If the frame is bowed in at the center? IOW, seeing "daylight" between the level and jambs/frame.

For correct operation of the window (warranty). No binding, "sticky" operation of sliders, etc.
It's hard to square an 8' door with a 6' level.
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• posted on November 12, 2009, 10:30 pm

I always measure the diagonals to make sure its square. For a prefab window they should be dead nuts on. Let's see, measure measure bump bump measure measure bump measure measure. Its that easy.
Jimmie
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<%-name%>
• posted on November 12, 2009, 10:18 pm
On Thu, 12 Nov 2009 13:50:52 -0800 (PST), DerbyDad03

Consider that two opposing sides have been shimmed too much and they are not straight. Consider that the bow toward the rough opening.
If you check with a level they would be level (or plumb) but the level would only contact in two places rather than the entire surface. This situation fulfills your parameters but the window would not be a square (or rectangle) because two of the sides would be curved.
Did I win?
Gordon Shumway
What color do Smurfs become when they hold their breath?
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• posted on November 13, 2009, 2:29 pm

re: "Consider that two opposing sides have been shimmed too much and they are not straight. Consider that the bow toward the rough opening."
How could shimming the 2 opposing sides cause them to bow outward toward the rough opening? I'm not arguing, I'm asking.
re "This situation fulfills your parameters but the window would not be a square (or rectangle) because two of the sides would be curved."
If you ran into this situation, don't you think that you would notice the gap between the frame and the level? I'm not arguing, I'm asking.
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• posted on November 13, 2009, 3:12 pm

If you shim too much at the corners, you could cause that. Or perhaps the window frame was bowed to begin with.

Yes, although you have to know to check that.
The main point is that a tape measure is alot more accurate than a bubble level. If the two diagonals are off by 1/8", I don't think that could be detected with a bubble level (depending on the size of the window).
Wayne
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• posted on November 13, 2009, 4:20 pm

Which is one of the reasons I like electronic levels. They're easy to recalibrate, have readings to 1/10 of a degree, have various reading units for different applications, you don't have to worry about your line of sight, there is a hold button so you can take a reading and then move the level to where you can see the reading, etc.
R
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• posted on November 13, 2009, 5:08 pm

Per Wayne's comment a 36" x 36" window where one of the diagonal is off by 1/8" the corner angle would be off by .3 deg (as I guess would the top or side as well).
Can .3 deg be resolved with a bubble level? I know my Smart level displays to .1 deg but how accurately I dont know.
A framing square would catch this small error.
cheers Bob
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• posted on November 13, 2009, 5:24 pm

OK, so if the window is checked square by a tape measure, why would I need to check it for level and plumb? ;-)
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• posted on November 13, 2009, 11:30 pm

A set of cross corner measurements will tell you if the factory window is square prior to install or after install but it wont give you the relationship of the window to the "house"
After installation the window could have been knocked out of square so a corner to corner re-check would be advisable
OR
it could have been installed "clocked" slightly off but still be square to itself. So a plumb or level mesaurement would catch that.
I think its a case of multiple views, measures, techniques to get to the same result...... a true, square properly installed window. Bouncing from one technique or tool to another is gives multiple checks.......when my buddy & I do door or window installs we do mulitple checks until we're satisfied and get to "good enough / shoot in it".
Performing multiple checks gives a chance to find a possible error.
I suppose one could determine the minimum number & type of checks to do but at least for me its......measure twice (3 times?) cut once.
cheers Bob
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• posted on November 15, 2009, 2:23 am
wrote:

OK, so if the window is checked square by a tape measure, why would I need to check it for level and plumb? ;-)
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• posted on November 15, 2009, 3:10 am
SteveB wrote:

people that look out the window will get seasick?
-- aem sends....
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• posted on November 12, 2009, 10:22 pm