83dons Posted February 27, 2023 Share Posted February 27, 2023 Hi I have an area in the garden shuttered off for concreting and I need to know the shape is near enough bang on square with 90 degrees each corner. The size is 5.8m x 4.9m so a rectangle. I have measured the 4 sides which all come out at slightly different lengths for various reasons to do with the setup of the wooden shutter and I also measured the two diagonals from corner to corner. My question is are there apps or online tools/software that I can input these measurements to get an accurate visualisation of the area (clearly this wont account for bend in the wood but will be reasonably accurate for corner to corner dimensions assuming the wood is straight)? Ideally this online tool would then indicate what the 4 angles in the rectangle are so I can see how close to square it is ie 90 degrees at each corner. Even more ideally the software would indicate how I should change the shape in order to achieve the perfect square (I presume to start with to achieve this that parallel sides would have to be exactly the same length is this correct? And that if so the diagonals would then be the same length if all 4 angles were 90 degrees). If no one knows of software solution is it possible to work out all 4 angles in the rectangle given just the length of the 4 sides and the 2 diagonals mathematically? Or would the precursor to this have to be at least that both parallel sides were of exact same length or does that not matter mathematically? My trig is sketchy and I just cant figure out how to square this shape up better! Any advice would be much appreciated on how I would approach squaring this off (bear in mind that the wooden sides do not screw into each other flush as the wood was cut exact length 5.8x4.9 for some reason not larger so they could screw into each other, this allows the corners to move easily and some have posts in so the ends of the beams are not flush which is not ideal - I wont be getting it completely redone so just need to make adjustments to make best of the situation and get it as square as possible as there isnt much margin for the summer house that is going on top). I am not able to use the 3 4 5 method as tried that but don't have the tools and area is too large for the wire/string to be accurate). I cant work out even if the opposing sides are parallel or off. See below for a graphic with the measurements in mm if it helps (i haven't included the mid point measurements as I can see the wood bows and I can just get these straightened out): Link to comment Share on other sites More sharing options...
nod Posted February 27, 2023 Share Posted February 27, 2023 The easiest method is to borrow or hire a rotary laser Set it running down one side and the dot that shines off the top will give you your 90 degrees Then move it to the next corner Link to comment Share on other sites More sharing options...
Temp Posted February 27, 2023 Share Posted February 27, 2023 Using the unPC Squaw on the Hippo (aka Pythagoras).... For bottom right corner.. Sqrt(4898^2+5787^2) = 7582 You measured 7630 so the bottom right corner is a tiny bit more than 90 degrees. For bottom left.. Sqrt(4898^2+5800^2) = 7591 You measured 7540 so bottom left is a tiny bit less than 90 degrees. So it's .pretty close just very slightly like this /_/ Repeat until you get bored. Link to comment Share on other sites More sharing options...
Canski Posted February 27, 2023 Share Posted February 27, 2023 does this help ? All square and fits on your slab 1 Link to comment Share on other sites More sharing options...
Canski Posted February 27, 2023 Share Posted February 27, 2023 Courtesy of Pythagoras. The builders best friend. Throw those foldable squares in the skip ! Link to comment Share on other sites More sharing options...
83dons Posted February 27, 2023 Author Share Posted February 27, 2023 (edited) 1 hour ago, Canski said: does this help ? All square and fits on your slab Hi I am afraid not. The square has to be at very minimum 5800 x 4900mm. Some of the lengths are under and it is definitely not square at each corner (well I guess it cant be if the parallel lengths on both sides are not equal is that correct thinking?). Is it not the case that I need to first make sure that each parallel length is pretty much the same then re measure the diagonals to see how much it is off square, then make adjustments as required to give 5800 x 4900 with as close to possible 90 degree corners? And to the earlier comment yes the bottom left square does look less than 90. My guess is that even after stretching the parallel sides to be same length I will still have a slight lean as you indicated, although I am not sure. I am just trying to get a practical approach to fixing. It is annoying they didnt cut the beams to say 100mm longer each one so they could just have screwed into each other to give a virtual square anyway. The way they have done it lends itself to inaccuracy and tilt on square but we are where we are with it and they wont recut the shutter so I need to try and get the thing nudged in the right direction to square it up. I am not sure it is worth getting the laser thing perhaps as trig should solve this I guess? Edited February 27, 2023 by 83dons Link to comment Share on other sites More sharing options...
Canski Posted February 27, 2023 Share Posted February 27, 2023 (edited) 23 minutes ago, 83dons said: Hi I am afraid not. The square has to be at very minimum 5800 x 4900mm. Some of the lengths are under and it is definitely not square at each corner (well I guess it cant be if the parallel lengths on both sides are not equal is that correct thinking?). You are not far out. If you want your minimum dimensions of 5.8 x 4.9 m then the diagonal is 7593 mm How wide is the timber frame ? 100 mm or larger ? you could hang the frame off the slab slightly to accommodate but I wouldn't go too mad. 23 minutes ago, 83dons said: Is it not the case that I need to first make sure that each parallel length is pretty much the same then re measure the diagonals to see how much it is off square, then make adjustments as required to give 5800 x 4900 with as close to possible 90 degree corners? Yes opposite sides need to be equal and the diagonals equal to achieve 90 degree corners. 23 minutes ago, 83dons said: And to the earlier comment yes the bottom left square does look less than 90. My guess is that even after stretching the parallel sides to be same length I will still have a slight lean as you indicated, although I am not sure. I am just trying to get a practical approach to fixing. It is annoying they didnt cut the beams to say 100mm longer each one so they could just have screwed into each other to give a virtual square anyway. The way they have done it lends itself to inaccuracy and tilt on square but we are where we are with it and they wont recut the shutter so I need to try and get the thing nudged in the right direction to square it up. I am not sure it is worth getting the laser thing perhaps as trig should solve this I guess? Edited February 27, 2023 by Canski Link to comment Share on other sites More sharing options...
83dons Posted February 27, 2023 Author Share Posted February 27, 2023 4 minutes ago, Canski said: You are not far out. If you want your minimum dimensions of 5.8 x 4.9 m then the diagonal is 7593 mm How wide is the timber frame ? 100 mm or larger ? you could hang the frame off the slab slightly to accommodate but I wouldn't go too mad. Yes opposite sides need to be equal and the diagonals equal to achieve 90 degree corners. The frame is just standard 44mm wide timber and I don't think each side is completely vertical. Do you mean tilt the top of the frame outwards slightly to extend the width of concrete at the top but not the bottom? I think one side already has this I would prefer they are all vertical I still need to check that also. Thanks for confirming the parallel sides need to be the same length I think that is the place to start first then remeasure the diagonals? Link to comment Share on other sites More sharing options...
Mr Punter Posted February 27, 2023 Share Posted February 27, 2023 1 Link to comment Share on other sites More sharing options...
IanR Posted February 27, 2023 Share Posted February 27, 2023 The bottom right corner (Between A & D) needs to drop 67 mm. If you are not extending the sides to the correct length, ie. side D to 5800, then perhaps only move the bottom right corner down 60mm, to half the error. Not aware of a specific App, but use a free piece of CAD software to draw it out. Link to comment Share on other sites More sharing options...
saveasteading Posted February 27, 2023 Share Posted February 27, 2023 The easiest way is to make one triangle using Pythagoras. If you have 2 tapes it is even easier as the third corner is where the 2 distances coincide. The corner is automatically square. Once that triangle is made, you have 2 fixed corners and a fixed diagonal distance. Then measure the other triangle to complete the rectangle. In your case length 5800, width 4898 and diagonal 7539. Link to comment Share on other sites More sharing options...
83dons Posted February 27, 2023 Author Share Posted February 27, 2023 To confirm, I will have to ensure the lengths are actually 5.8 x 4.9m or as close as possible or they will be too small, then remeasure the diagonals is the best approach (and then if still not square then the whole frame will need moved slightly will it)? If I dont get the parallel lengths the same I am guessing it can never be square? Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 27, 2023 Share Posted February 27, 2023 I’m afraid the easiest way to do this is to start again. You messed up, so stop and start again start with your 5800 wall, build this exactly to the length you want 5800 then cut a wall to the next length and fit it at exactly 90 degrees. You need to look up the 3-4-5 rule this will give you an accurate 90 degree corner. No amount of messing with what you have will get it right. If one wall is short in length you will never get it square. Take it all out and start from the 5800 wall. Go on YouTube to look up 3-4-5 setting out. Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 27, 2023 Share Posted February 27, 2023 Your post reminds me of those 'O' Level maths problems where the challenge was mostly - whats the question? The maths involved is simple. 3 hours ago, 83dons said: Hi I have an area in the garden shuttered off for concreting and I need to know the shape is near enough bang on square with 90 degrees each corner... What - for you - does near enough bang on mean? Buy a roll of string and four pegs. Mark out the largest exact (?) string square within the shape you have already got. There is your error margin right before your very eyes. What's near enough? You decide. Link to comment Share on other sites More sharing options...
83dons Posted February 27, 2023 Author Share Posted February 27, 2023 53 minutes ago, Russell griffiths said: I’m afraid the easiest way to do this is to start again. You messed up, so stop and start again start with your 5800 wall, build this exactly to the length you want 5800 then cut a wall to the next length and fit it at exactly 90 degrees. You need to look up the 3-4-5 rule this will give you an accurate 90 degree corner. No amount of messing with what you have will get it right. If one wall is short in length you will never get it square. Take it all out and start from the 5800 wall. Go on YouTube to look up 3-4-5 setting out. You are misunderstanding I only have the shutter down the concrete isnt poured yet. It can certainly be fixed. Link to comment Share on other sites More sharing options...
83dons Posted February 27, 2023 Author Share Posted February 27, 2023 31 minutes ago, ToughButterCup said: Your post reminds me of those 'O' Level maths problems where the challenge was mostly - whats the question? The maths involved is simple. What - for you - does near enough bang on mean? Buy a roll of string and four pegs. Mark out the largest exact (?) string square within the shape you have already got. There is your error margin right before your very eyes. What's near enough? You decide. I tried that already its not possible due to the large size of the area. I am attempting to use Geogebra software to do the same thing but in a more exact method. I would think from what I have seen so far the frame needs changed for sure to give more comfortable margins. Link to comment Share on other sites More sharing options...
saveasteading Posted February 27, 2023 Share Posted February 27, 2023 6 minutes ago, 83dons said: attempting to use Geogebra software It is ok to struggle with geometry. Rather than rely on software, which still needs understanding of the principles involved, can't you ask a friend to help you with this stage? Link to comment Share on other sites More sharing options...
Mr Punter Posted February 27, 2023 Share Posted February 27, 2023 If you cut the timber to the lengths you want, rather than have a few mil difference in opposite sides, you can just screw it together and square it by making the diagonals the same length. 2 Link to comment Share on other sites More sharing options...
Temp Posted February 27, 2023 Share Posted February 27, 2023 (edited) 1 hour ago, 83dons said: I will have to ensure the lengths are actually 5.8 x 4.9m In which case the diagonal for that should be 7.593 m Edited February 27, 2023 by Temp Link to comment Share on other sites More sharing options...
SteamyTea Posted February 27, 2023 Share Posted February 27, 2023 Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 27, 2023 Share Posted February 27, 2023 46 minutes ago, 83dons said: You are misunderstanding I only have the shutter down the concrete isnt poured yet. It can certainly be fixed. Nope. How are you going to grow a piece of timber from 5787 to 5800. You need it 13mm longer, so unless you are going to put a 13mm slither in then you won’t ever get it square, you will fight with that for hours. Start with one piece and get that right, then add the next bit at 90 degrees. Trying to get 3 incorrect bits of wood right will be a pain. Get one right and then the second. 1 Link to comment Share on other sites More sharing options...
Canski Posted February 27, 2023 Share Posted February 27, 2023 do you have a 20 m tape measure, 3 pairs of hands and a nail ? Link to comment Share on other sites More sharing options...
SteamyTea Posted February 27, 2023 Share Posted February 27, 2023 50 minutes ago, Russell griffiths said: Trying to get 3 incorrect bits of wood right will be a pain. Piece of piss. Link to comment Share on other sites More sharing options...
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