Establish Hip Length - Calculation

[@paul_9128]

HI BuildSum, thank you for this explanation, concise, to the point, and easy for the boys to refresh their learning during smoko, on site, some times good trades men can spend a lot of time truss framing. This video maintains the craft in the trade. Cheers Ace.

[@Buildsum]

Thanks Mate, great to hear that you are finding them useful.

[@twentyonetwos3967]

Excellent video again. Great to know all the alternatives however awkward they maybe. Most of your videos concentrate on single storey construction, whilst the majority of building I see built are two storeys. Although I expect that the methods and techniques are similar, there are some intrinsic differences and I was wondering whether you could enlighten us. I thank you for your patience. Regards, Maurice

[@shizzleinthenizzle]

at 4:30 for the ridge deduction, we were told to half the thickness of the ridge. Here you are saying half the thickness of the common NOT the ridge. Is this right ? as commons and ridge are nearly allways different width materials so it will matter ? thanks!

[@Buildsum]

Hi Mate, because we are working off the span of the Crown end rafter then it is half the common rafter distance, not half the ridge.

[@shizzleinthenizzle]

@@Buildsum awesome thanks. another quirk with hips learned.

[@robtien7]

What point of the tail is the measurement to? Is it the long point?

[@Buildsum]

Hi Regan, all the measurments are calculated to the long points of the hip.

[@aniton11aniton11]

In step 9 you added the eave width of 450mm. Shouldnt this be longer due to the hip travelling a longer distance(compared to the commons) to meet up in the corner? In plan view yes the overhang of the hip equates to 450 but when I draw this on plan the length of overhang is 637mm +/-

[@Buildsum]

Hi Aniton I add the eaves width to the 1/2 span of the roof because I have worked out a ratio so for evey metre of the 1/2 span I know how far the True length of the hip would be per metre. You are correct the hip plan length is definently longer that the Eave width and the true length of the Hip is longer again. Hope this helps

[@aniton11aniton11]

@@Buildsum would great to have a video on how the jack rafters are calculated and marked on the timber also :-)

[@Buildsum]

Hi Aniton, I cover off on that in the Pattern Rafter for a hip roof video kzbin.info/www/bejne/ipSxZIJtpNyab6s

[@wiggthepig]

Helpful. Thanks. Been going through this step by step to get my head round it. Am I correct in suggesting that point 9 in this tutorial is incorrect? The true length of the hip is surely 3.779m not 2.475m?

[@Buildsum]

Hi, Will Yes as per Point 8 the length of the Hip without any deductions or the overhang is 3.779. The 2.475 is the plan length of the hip before we make the deductions and add the overhang in point 9

[@wiggthepig]

What confused me what the final part of the video, cutting the hip. Mark the plum and edge cuts, then measure down 2.475 to mark seat cut, then measure 4.477 to include eave length. I would have thought the measurement from plumb cut to seat cut would be true length of hip (3.779m), not 2.475m as explained in the vid. That's where I got confused. Perhaps I'm still not right!

[@Buildsum]

Hi Will, no you are correct I should have said 3.779 to the back of the Birdsmouth, sorry about that I will fix the video up now.

[@aniton11aniton11]

Am I correct in saying that the plumb cut angle on the hip (top and bottom) will be different to the plumb cut on the commons

[@Buildsum]

Hi Aniton, yes, because the hip has a longer run for the same rise, then the angle is less and there for the Plumb cut will be a lesser angle.

[@aniton11aniton11]

@@Buildsum is there a way to calculate what this angle would be with a formula or is it worked out on site?

[@Buildsum]

Hi Aniton, you can calculate it however it is more commonly developed geometrically. I have a heap of videos on the different ways that this can be done. kzbin.info/www/bejne/hJe2nIeKaJqIpas kzbin.info/www/bejne/rIXWkpilp9GArsk kzbin.info/www/bejne/r3zCh5-kp52VfqM kzbin.info/www/bejne/n5-2fmmrpa-ZadU just to get you started.

[@wheres_bears1378]

For the top plate cut why do we divide by 2?

[@Buildsum]

@@wheres_bears1378 I'm not sure which one you mean, sorry

[@wheres_bears1378]

@@Buildsum the cut where there hip rafter sits, you were saying to times half the rafter with by the hip plan run then divide by two. I think I got it now though, it’s because we are splitting it over two top plates that’s why we divide by 2

[@Buildsum]

@wheres_bears1378 it's more to do with getting a dimension thats in line with the half span from a dimension at a different angle

[@wheres_bears1378]

@@Buildsum ok yes I understand now, thanks heaps for your help 😊

[@michaeltomlinson9803]

i do have a quick question , i use the red roofer book to help me with roofing calcs but at the top of every page it states the pitch and next to that it has a measurement in feet do you know what this measurement in feet means

[@Buildsum]

Hi Michael, is it in feet or inches? In America, they express the rise of a roof in inches per foot, for example, a 27 degree (26.6 to exact) would be a 6 inches in 12 inches. I am guessing that this is what that measurement would be. hope this helps

[@michaeltomlinson9803]

@@Buildsum hi yes, this is in feet for example 25 degrees and next to it 38 feet the next page 26 degrees next to that 34 feet

[@Buildsum]

Hi Michael, I'm now pretty sure that the "feet" measurement that you are referring to is actually "minutes" as in degrees, minutes and seconds. None of the angles in the Little Red Roofing Book actually equal an exact degree as they all come from the imperial ratio system as I have previously described. So it would be 25 degrees. 38 minutes of angle not exactly 25 degrees. Hope this helps

[@michaeltomlinson9803]

Great thanks mate

[@weldonpinder7295]

Why do you use meters? I was considering this to be a well explained video but the simplest way is in feet and inches

[@Buildsum]

Hi Weldon, I live in Australia where we only use metres thats why. Personally feet and inches don't make any sence to me however I have never had to use them.

[@robtien7]

What a stupid comment. There's plenty of videos on this topic in your outdated imperial system

[@weldonpinder7295]

@@robtien7 it's not stupid if I don't use or understand meters.

[@robtien7]

@@weldonpinder7295 its universally accepted that the metric system is easier to use than imperial

[@radunini6425]

What is "tan"?

[@Buildsum]

Hi Radu, the tangent (abbreviated "tan") is the ratio of the length of the side opposite the angle to the length of the side adjacent to the angle. this means that if we know the Horizontal measurement of our member and the angle or pitch of the member we can use the TAN function to work out the Rise of that member. Most scientific calculators have a Tan button that you can use to do this function. Hope this helps

[@karanchohan1539]

Aussie aye