newbie builder with a general question. I am building a cottage that is 24’x28′. what is a reasonable error to expect for when measuring the diagonals to check for square?
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Replies
Well, depends on how fussy you are, and what stage of construction you're talking about. Within an inch is pretty good, and a quarter inch is almost too perfect. But be sure to double-check the side measurements as well -- if opposite sides aren't equal length you can be dead on and still have a nasty trapezoid.
Note that it's important to set your tape the same either way -- the tip must hang on the outside corner of the form or frame in an identical fashion in both cases. Sometimes you may need to construct a fake corner to account for a jog in the wall or an irregularity in the form.
The technique is most sensitive (greatest measurement difference for a given amount of skew) with a near square (as in your case), less sensitive with a long, narrow structure.
Sometimes, in difficult cases (odd shape or difficult terrain), it's better to establish one corner via a 3/4/5 triangle and then set the others just based on wall length. Or measure two adjacent walls and calculate the proper length of the hypotenuse. But the opposite diagonals technique is generally the most accurate.
thanks Dan. Just got finished putting on the subfloor on the second floor and ended up with 1/2" difference in diagonal measurements which to me seemed to be pretty reasonable. Thought I had better get a second opinion since this is a cottage I hope to pass on to my children.
Heck, for them you should make it "interesting" -- make up for all the grief they've caused (or will cause) over the years.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
It might be worth mentioning that diagonal measurements don't mean much if the opposite perimeter measurements are not the same. You always have to check those first. If your side lengths are correct, the difference in the diagonal measurements is only half of what the building is out. If one diagonal is a half inch longer than the other, you are only out of square about 1/4".Beat it to fit / Paint it to match
And, in fact, with a nearly square building the amount of skew -- the amount that one side is slid sideways relative to the opposite side -- is only about 2/3 of that quarter -- less than 3/16"
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
You are att the perfect point to correct this by snapping your layout lines for the walls so it is just right. Letting one side hang out 1/8" and sucking another in 1/16" or whatever it takes. Let it go and the error will chase you allllll the way to the ridge, and cost you time and aggravation, especially if it gets worse as you go.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I agree. If my deck is out a little I adjust the plates a little to get them closer.
ditto. when a guy challenges me on stuff like that saying "it's close enough." I say how much harder is it to get it perfect. There are the other times when you have to know how to "hide" something.
I think 3/16" is indeed "close enough", since normal warp in the wood will contribute more error than that, and you can't eliminate the warp.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I say how much harder is it to get it perfect.
So you adjust things to make your part perfect because that's what makes you happy, then the siding guy has to deal with uneven transitions.
Some of the most important things a carpenter does everyday involve foreseeing how his framing will effect the tradespeople who follow him. It takes a different mindset to recognize how to make things work well for the entire house.
what? I worry about my part as a whole. lets not turn this into some silly debate.
I back up my building attitudes with the fact that everyone who followed me thru my own home that I framed myself, made a point to comment to to me how great the framing was or that they havn't seen a house framed like that in a long time - including drywallers ( more than once) cabinets installers, window covering rep. ( "all the windows are exact" she said.) Even the Building inspector commented that he was impressed with the framing. As far as the trim guy goes, I did the trim. I still found things that I personally felt could have been better. MY siding guy had no problems and we hit it off, enjoying talking about the pride we take in our work.
I live in a $400,000 neighborhood but my framing comes from years of framing in 4 million dollar neighborhoods. The crew I learned from had a rep of other trades loving to follow us. That makes me happy, and the end result. there's a whole lot more to it than "my part".
I worry about my part as a whole. lets not turn this into some silly debate.
It's not silly. You agreed with a post about correcting something which might better be left as is. Yours was the last of three posts echoing the same sentiment, so I took a quote from you to make a point which should be considered by the OP.
Glad to hear that you follow good procedures, from the ground up. That's always been my approach too.
Edited 6/7/2007 4:50 pm ET by Hudson Valley Carpenter
thanks to everyone for all the input. seems like a few people got a little hot on the topic. As it turns out the difference in diagonals turned out to be a little under 1/4". Checked the first time on my own but when I rechecked with a helper it was better. dumb end of the tape must have been twisting. At that point in the construction I was able to snap perfectly straight and square lines for the second floor layout and I didn't have any issues getting the engineered roof system in place. I am trying to attach a picture of where I am in the framing stage. Thanks again.
who the gurl
Holy mother of pearl, Batman! Is that thing ever built!
But....uh ya forgot somethin'. Unless you plan on using your extension ladder to get to the second floor. ;-)
I will take that as a nod of approval. Still have some learning to do before I tackle the stairs!! Getting the outer shell up and weather tight first.
I will take that as a nod of approval.
Absolutely! Looks like you've done an excellent job.
I'm just blown away by the amount of engineered structure that's built into that house. It's a huge departure from what vacation homes were, even twenty years ago.
just an old stick builder...
what's the poly for? View Image View Image
poly was installed before putting on the roof trusses to give me a continuous vapour barrier. I am using a product called p2000 for insulating. the poly will tie into that.
Youv'e got me curious. is the poly hanging on the outside excess, to be cut off later? is your insulation on the outside of the house? can you tell me how everything ties together. View Image View Image
here it goes...first of all, the insulation is a foam panel with foil covering both sides (P2000). I am using the 1" thick panel and in the upstairs it will be on the underside (warm side)of the roof trusses. the poly will get tuck taped to the inside face where they meet at the floor. above the poly in the roof cavity there will be an amount of batt insulation where the roof trusses meet the floor, where it transitions from inside to the outside wall the poly is the vapour barrier and as such could only be installed before the trusses if I wanted a continuous seal. once on the outside the insulation then goes on the outside of the wall framing and the poly will be tuck taped about 1' down one the outside creating a continuous vapour barrier from attic to outside wall. Also continues under the first floor but you asked about the poly. the P2000 acts as insulation and vapour barrier so the only weak point was at the roof transition. How do you like that?? I am open to any suggestions.
well here goes second time- really sleepy and I just spent half hour to write you answer and then somehow I deleted and lost the my response to you...lol oh well.
sooo, here we go again.
I think it sounds like you have a really good thing in mind as far as R value, do you know what it is? what I want to know is will you have pony walls? which will create a cold zone - unless you plan to heat that area. if you plan to run the drywall straight to the floor as per current framing in picture, then what you have done is fine in that regard, and make sealing things at that junction easier - I like you planning ahead thought process. If however it will be a cold zone, your poly will run down the underside of trusses and down the inside of pony walls and be sealed at the bottom plate of the pony walls, making the poly where you have it now pointless.
The other thing that causes me to ponder is that you should be having insulation in your floor trusses around the perimeter of your house. normally the poly goes on the inside joist cavities sealed at that point. so with your poly running 1 foot down on the outside, have you now created a strip around your house that has potential to trap moisture?
That's not exactly what I wrote the 1st time, but I'm too tired to remember it all. View Image View Image
I get what you are saying......i must be awake enough for both of us.
there will be some pony walls but they will be in a warm zone. insulation goes right to the intersection of roof truss & floor. Then I will frame the pony walls on the inside of that giving me storage area in that cavity that is in a warm zone. I plan on some built ins for drawers to eliminate the need for dressers and closet space. makes use of otherwise un-utilized space.
As far as the insulation in the floor trusses, the need for that is negated because the insulation on the outside of the walls totally encloses the outer shell. it gives a continuous insulation/ vapour barrier layer from the top of the second floor trusses to the bottom of the first floor trusses and at the same time eliminates the thermal bridging through the studs. If you look closely at the picture you will see that I have some 1/4" P2000 between the floor joists and the girders on the first floor. I will seal the joints where the outside wall insulation meets that insulation and then will be dragging my butt underneath to put the same product on the underside of the floor trusses and seal all those joints.
R value is reported by the local distributor to be around R-26 for the 1" thick panels. The number I think really represents what R value equivalent you would have to build a batt insulation system to in order to get the same performance. The primary benefit of the product is the reflective qualities of the foil that eliminate heat transfer through radiation.
Sounds a little hard to swallow on the r value for a 1" thick eps foam sheet but I am going to give it a try. A local builder has been using it exclusively for a while here and it seems to be giving good results. If not I will be adding insulation inside before all the drywall goes on. going to wait a year and see how it performs.
ok I missed the part about the wall insulation being on the out side.
unless the storage attic space is heated it is still considered a cold zone, but I'll bet you will never have a problem with it. building envelope science is still something I never quite fully understand at times with certain scenarios.
I think your house will be warm and toasty and nice and cool.
what kind of siding will you have and house does it fasten? View Image View Image
since it is primarily a summer cottage I want low maintenance and a rustic look so I am leaning heavily toward a cedar siding. either shiplap or tongue & groove. Going to put strapping on the outside of the insulation down each stud and run the siding horizontally. Not going to put any finish on and just let it go grey. Actually having a hard time getting advice on whether that is a good idea or not. Might be the subject of a future post.
I hope the second floor is a bedroom of some sort- that looks like one FANTASTIC view out the back!!!
Master bedroom is facing the view! Perfect southern exposure too which was a bonus to go with the view.
where do you live mdcc? looks similar to my region.
southern New Brunswick, Canada. The view is of Bellisle bay. the bay ties to the Saint John River system which is some of the best recreational boating accessible from the Atlantic. Just plan for the tides!!
It's alot better to make it square before you stand the walls up and have to tweak the siding a little than have to tweak base board and crown moulding on the inside.
Another issue is trusses or rafters. THe closer to square the house is the better.
Edited 6/7/2007 5:13 pm ET by Stilletto
Are there people who do not square the foundation and install the sills square? Do people not pull parallel measurements for the rafters walls?Why would anyone NOT square the foundation and put the sills down square?Check you box and make sure everything is square. After the decking is down, make sure everything is square and parallel. What in the world is so hard about this?One inch is close enough?????????? WHAT????!!!!!!What's going on here? Joe Carola
I square from the foundation up. 99% of the time thats the way it finishes.
Once in a great while something happens and an "adjustment" needs to be made.
By adjustment the worst I have dealt with on one of my frames was 3/8's over 52' corner to corner.
On new work I was taught to follow the foundation and put the sills,joists and decking down.After the decking was down, then we squared up everything, by sticking the shoes past the box. Before the sheathing we would shim out the box.I thought that was nuts as a punk kid. When I started my own business, I never did that and I squared the foundation and snapped out square and parallel lines and keep everything square from the start. It makes no sense not to square the sills. If for some reason you make a mistake, you should catch it when you snap out every single wall and nail them down square. If your walls are still reading out of square and your second floor is out of square then you f####d up. First floor walls and second floor deck should not be out of square. It's that simple.Joe Carola
Squaring at the sills is the only way to start. I didn't learn that way though. I was taught to follow the foundaton as you were.
The place I have seen the out of square deal happen is where someone nails on an LVL without squaring the end. We get some very wild ends on our LVL's at times. It gets nailed on and it throws a corner out of whack. Pretty easy fix if caught before the glue sets on the subfloor.
And sometimes I screw up the sun starts to cook the brain and I start getting my numbers crossed. Either way not the end of the world.
Been waiting for you to show up framer. Although you and I sheet walls differently. I knows you gonna make it square.
had a kid mess something up one time and he says to me "well we aim for 100% but you not gonna get it all the time"....true...but you were sloppy on something easy - do it right.
?......are you adressing me?
make it square I say...did I say something else?
>>?......are you adressing me? <<
Yes your majesty. I was addressing you. In broken internet english I was agreeing with you. I went back and reread my post and it was vague in that aspect.
Sorry for the confusion, I am going back to my corner now.
lol.....
all is forgiven :P
Good deal.
around here its been measure to 1/8 build to 1/4. if its out by 1/2 then it would be measure to 1/2 build to 3/4.A man is a success if he gets up in the morning and gets to bed at night, and in between he does what he wants to do...
an inch!? Are you kidding? I must be too perfect. Quarter inch is max before I start wondering where I went wrong and looking how to fix it.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Are you laying it out or is it finished? The allowable out of square figure changes according to one's ability to rationalize. ;-)
Most of us work to +/- 1/8" as our ideal on most measurements for height and square but I'll accept a bit more on a diagonal such as you've described. Plus or minus 1/2" is acceptable...after a bit of bitching and cussing.
Edited 6/5/2007 1:31 pm ET by Hudson Valley Carpenter
I am at framing stage and just finished the subfloor on the second floor. 1/2" out on the diagonal measurement seemed good to me but I thought it worth getting a second opinion. Thanks.
At this point what can you do about it? Not much. This is when the craftsmen in you must figure how to hide it if it can be noticed without using a tape.
Grandpa told me long time ago the difference between hacks & craftsmen is how well they hide their mistakes.
1/2 inch is alot, you need to kick one corner to get it to 1/8.A man is a success if he gets up in the morning and gets to bed at night, and in between he does what he wants to do...
Yeah, I say tie a corner ot the bumper of his truck and tug it square. ; ^ ) Mike
Trust in God, but row away from the rocks.
I am at framing stage and just finished the subfloor on the second floor. 1/2" out on the diagonal measurement seemed good to me but I thought it worth getting a second opinion. Thanks.
Sure. Now's the time to work on getting the exterior walls straight, bottom and top. That's something that can be seen when the house is completed so it's worth the effort to get it real close.
Edited 6/6/2007 11:01 pm ET by Hudson Valley Carpenter
You'll find ( or at least I find) that the amount of tolerance one has to accept a flaw, depends on two things
A: the degree of the flaw
B: the degree of effort it takes to correct ( or in some cases hide) it.
Half inch to me is a lot. and I will be more than happy to spend 10 minutes adjusting things to fix it - or longer. some things will hide easier than others and it is experience that helps one know what will hide easy and what will show itself.
generally speaking if I can spend a bit longer to get it right on, I will. I'll surpass the 1/8" tolerance if all it takes is two more taps to square up a wall to dead on. But sometimes you have to learn to live with a flaw that isn't worth the time in the end, or you will never sleep at night.
Half inch to me is a lot.
It could be if it weren't the difference in diagonal measurements. A half inch is actually plus of minus one quarter. Having the second floor deck out that much won't cause any problems for anyone down the line.
Why would you want to check for square?