Roof Construction ~ Extension Build #7

[Music] the overall plates are 850 and the pitch is 45 degrees so that number is 1.414 so there's two ways of doing it so the top way is 4850 minus the ridge gives us 4 760. divide that by two because we only want half of it two three eighty so now we've got from this line down here to outside the plate yeah it's a two three eighty times it by one point four one four it's three three six five that is our length for rafter right so the one four four you get from your chart four fours from the chart that's just um the code sign of the multiplier multiplier but the other way of doing two is two ways that way it's the overall lesser thickness divided by two yeah or half of the span two four two five then take off half the ridge yeah so then because half the span is the center of ridge yeah so 450 divided by two two four two five that's half ridge it's only 45 we've got 90 mil reach 238 times it by one point four one four three three six five got it okay yeah i think if you can't do that then you shouldn't be doing the job no become a bricklayer which size you want on the top top oh you wouldn't yeah i love groaning like an old man didn't i you do yes you're getting oscar one day dan this is a a very nifty little workbench you've got is this one another of your inventions just don't move around too past much and that's not gonna look like damn much trouble now spread it and it's just that's fantastic i do fall for a starter what he's worried about he's not working imperial imperial square market well that's that one next one [Applause] we've got a couple of videos last morning don't work [Music] so our lovely engineer friend has decided that we need a double 9x2 ridge it's a beast number twos are heavy at the best of times they're wet soaking wet um the ridge is nine and six meters long probably a little bit more so to push both of them up in one go bolt it together it's not gonna happen so we're gonna have to find out a nice little nifty way i'm sure daniel's got some some tricks up his sleeve for this one so i'm going to land it over to him i think all right okay so um you haven't got a sister there's it they're not going to be joined you've got it in one length have you the ridge uh no they've got to be we couldn't get it in one week it's actually over six meters sorry it's about six um it's almost eight meters i think actually oh my goodness yeah because we've got an overhang on the front so going past the gable the building in total is just over 10 meters long we're not coming all the way through because we've got an intersection here yeah from the from the main house but yeah it's nine or eight meters long um so we're gonna have to do it in four pieces essentially so when you cut those rafters did you allow for the double region yeah well daniel did he did did he yeah i hope so no he did he definitely did we'll try a few up before we uh lift anything up but i suppose the good thing there you've got to cut a bit off because you're not trying to add a bit on yeah yeah definitely so we'll offer up a couple of rafters together with two blocks of uh two inch stuff see how it's looking and when we're after with it we're gonna what i think what we'll do is we'll bolt the timbers to one side lift one side up then the other side so what are you going to bolt them with i don't understand what does that mean um well we're going to screw them so how are you going to screw them then okay so first thing we screw the rotor to the the plate we've got some uh forge fast screws that we're gonna bolt them onto the plate first lift that side up do the same with the rafters on to the other part of the ridge lift it up together they'll drop in nicely together in theory yeah they will it definitely will yeah and then we've got some uh forge fast screws that we can fit in from both sides all the way through and because it's not in one continuous length and we're having to sort of stagger it yeah but these forged fast driving nice and fast and reasonable price or another true story james is too young yeah right there's a true story statement in the afternoon oh steve he's still on now sometimes listen to that when the brick is and you and we both slide it over that way yeah yeah all right what is that a poor man's scarf joint then [Music] that's a good hammer that ian's yeah it's like me and my spirit levels i'll do it i'll do it till next week oh i've actually got a hammer here i should use it should i well i think let's just go straight if you would prefer you used it then use this battery [Music] it's gone they are absolutely perfect every single one probably what's not helping is that prop is pulling it over this way put this one in take the prop out and then bash it around a bit and get the top set out oh nice straight one that's too much doing it trying to skin a bit more off yeah take it up to you 100 ml off it you're not bad rog 115. take 120 off perfect that's it spot on i see all the boys on the festool talk group they they put an espresso machine in a sustainer with a little thing full of pods and all that i mean come on now dan's brought a square with him he has indeed another square another one we funny enough very kindly sent us model one yeah model two now this is a bit of kit this is really something else i just explained to viewers daniel invented this square it's a roofing square and uh you made a bit of a modification to it a little bit of feedback and uh everything now we've got all the hip plum cuts around on the outside arc where it says hip here yeah we got around originally i just had the plum cuts when i first invented it i was unsure how it was going to sell and you were a bit worried that it would be too complicated for too much on yeah but yeah you know everyone loves it and um we've now got the hip-hop cuts around here so that one that one's also got this is it yeah it's also got it um i'm just enjoying watching danube i don't know how it works all right so this is the new square roof pitch this is the main roof pitch then around here we have all the hip plumb cuts so obviously you've got a 40 degree pitch roof there stick it on 40 up here and then you have your hip plumb cut right and just explain to people who don't know the reason why the hip is different so in this case you're going to be doing a 45 degree roof with james 45 degree roof on here and the hip it's normally between 9 and 11 degrees lower the hickory slightly lower and it varies depending on the pitch because a few people said why these numbers slightly different but um yeah i think 45 it is around 35 degrees that's interesting that that that's really baffles me so what you're saying is that as the angle of the main roof changes it doesn't change it's not um by the same it's not constant no it does very little between nine and eleven i don't know why i don't know why that's going to keep me awake at night trying to work out yeah no that that it's really baffling isn't it constantly one number but yeah it does it does change oh dear we need we need a really clever mathematician to explain to us why that is james you've got to grunt like an old man i was trying 3365slm then any any calculations that you do it's always on the top edge so we line that up there and when we drill down here that is our plate that's our seat and plumb cut to sit on the plate this is the measurement now any apps that you've got it'll always be dana's top edge then you need to plumb it down yeah it's no good go into eggs that's inaccurate the square one is set up to automatically give the birds now so once we line it up there mark now that's it yeah when i got here from working she'd been watching them she said i won't she said i want your autograph i'll tell you what that ridge is looking nice and straight now which is just as well yeah the rafters straightened it out yeah oh definitely yeah yeah it's following the wall plates now yeah yeah yeah i'm good it's gonna be on the money getting narrow food [Music] we'll fit this one in we've worked it on measurements from all of the ceiling rafters along the bottom and we've got the same measurements marked out all the way along the ridge we know that that position on the plate is our crown rafter position so we fix that there we'll fix it according to our measurement up here but we don't know if it's square yet so what we need to then do is make sure all of these rafters for at the length of it are plumb once they're priming up right that's the final position so you put a spirit level on there or plumb bob or what i think we might go plumb bob in action well we'll go plumb bob then so once we're we know that this is plum and they're all fixed with a diagonal piece down we can then cut an identical rafter here this will be cut off and we can put it straight down to that plate there yeah and that will be like a double sure way we know that this is everything's plum and square you cut this one 200 mil longer didn't you on purpose i have to double check my measurement now these foods fast enough to drive in well look at that stick a spike in that one i'll get it i'm up here that's even better for us in that means we're going to be going further you cut it down to 200 and if we need to put a little packer in there we can we'll put a double in the i think jones and then we get the ridge off of that yeah whatever level it is on the other side it'll go down to it just put it down to wherever it's and then i'll get the hip in it's always a trouble when you're patching into an old existing building so there's been a little bit of a bit a little bit there you know trying to get it right yeah but it's actually coming out well the thing is you couldn't strip that roof back very much not at all to get the line through could you because there's a glass roof consumption below the house is all finished inside yeah you start stripping it but you have a sudden downpour like we had this morning yeah yeah it could really do some damage you know the lofts all fill up with old stuff so it's not practical to strip it all off so the best wheel in the world you just take a punt you just think that's where it is that's what we're run with yeah and hopefully the tilers are your toilets are great they'll get over it those those plain clay towels they allow a little bit of i think they'll allow a lot yeah see there's shape of some of them yeah yeah now it'll be fine i mean we've got the top of and the bottom of the existing rafter exposed the last one i've been inside the loft space they're nice and straight throughout so it's not like the last one's dropped massively so you know it's going to be fine it really will or the one in now we're going to fly through and then i've got that and then it finishes at that are you making this up as you go along i've gotta go check my book now chapter three putting the ridges so that we'll go to [Music] is that good down hip's going to come down here we've got a double nine inch timber so we've got two timbers coming down on the hip double hip so first one we'll do that 45 across there and then i want it uh 90 mil the thickness of the of the hip so that's it lovely and that should be it's about 90 mil yeah i'm just at 90 mil so we'll cut that off and the hips gonna sit on now then now trim this bit out right on the hip because it's a double this is the sort of plum cup we grab it's going to be a big old miter on now so we'll do one plum one got splay cut a bit of timber and then sit down so to get that we've done a 45 degree pitch there's a hip plum cut 45 degrees what we're doing and actually see that it's like it's in real money it's 35.5 or something the main pitch to the roof is 45 degrees and this is what bed it set on earlier so now we're going to put the hip plumb cuts on it so around here we've got a scale and for a 45 degree pitch roof we put 45 on here for a hip plumb cut and that will give us the hip plumb cut for 45 degree roof so it's automatically adjusted automatically adjusted so we pull it on to give you the equivalent and that won't be a 45 degree that's not fully cut but it would be as if it were 45 it as if it was 45 for the hip plum cut the main roof is 45 degrees and the hip is always a little bit lower because the hips longer from the wall plate to the ridge so because it's longer therefore it's slightly lower it's normally around 10 degrees lower so the hip is always longer but it's a lower degree pitch from the ridge to the plate so because it's a lower pitch it's always longer and that is why it's a shallower pitch on here so you don't have to worry about this because my square's done all working out for you it's got all the markings on here ready for you for whatever pitch roof you're doing so with the square set on 45 the hip plum cut i'll put that here drawing down it and that's going to be our top plum cut yeah now i'm going to put the saw on 45 degrees and cut through now to get our bevel cut it's not 45 but you put saw on 45 and when you cut through on this angle it sorts it out and does it for you and nobody knows why i don't know why these are our hip off cuts and this is what the hips going to be like so normally when i'm doing them if it's a two inch hip i'll leave it two inch um but because it's so wide we're going to cut the angle down there put a dihedral angle on it oh because i just think that's just too wide but i don't want the batting to come a lot of time a little bit yeah so i'm gonna off that up there and draw around it to get me angled so you're not going to work it out but the easiest way to show everybody is just to get it up there and draw around it because it's tricky that dihedral angle isn't it a lot of people don't know the times really yeah it's very rare because most hips that are putting it's either metal or we just put singles in but that's just a little bit too wide so we'll give it a nice little cut and uh get that marked out and start ripping these down yeah right over the top there there we go marking the hip bird's mouth out this is an important measurement height above the plate and a plum plum up there 148 mil up now okay on the plum yeah that's what we need so what i'm going to do now is going me cut there i'm gonna measure 148 mil down there on the plum now i'm gonna set that up now normally when it's square and that's sitting hard down but because we've got a bit of angle on it it's it's a little bit but i'm going to slide that down i'm going gonna keep that flattened and down to there so one four eight now the other thing that we've done me and jones we measured from our longest point to the wall plate just two fixed points i can't change them but when we first started smalling with the blank canvas i measured to the top because that's how the measurements work but now i'm going to measure to the plate yeah let's see it four two seven three round now once it makes it line there let me go down now and down there now be mine should be okay obviously you've got the plate and a bit of block work that looks a bit too deep is that more than a third it is more than a third it's near a half quite often all the hip birds mouths and because it's shallower um and how it works out it's a bigger bird's mouth there's nothing you can do about it but that's why this is nine inch all their rafters are 156 inches so it's still it's a nine inch so yeah it's a big old bird's mouth but that is just how it is you can if you had that as a third you'd have no bird's mouth on your raft because that'd be up from higher got it but we fell out when he never look at it how's that looking james he's nice and flush with the top of that [Music] oh maybe you want to cut them jackson not that much the 45 up there i'm thinking that we're at that height on them ones is that they're going to matter that we're not um up there i suppose it only matters equal pictures if you're putting um valley tiles in yeah but if you're putting them in i mean you can change them a bit but you want them similar yeah but these are lead valleys anyway so it doesn't matter right whiskers it's another five of those dan and then we want to maybe a short bit down there i want to make my loft into a a bit of a space play with my train set there's certain things you've got to think about aren't they like the triangle is very very important so what's going on just just give us an idea of the structure how it works the way your roof works obviously you've got this triangle that's that's fine that's where your tiles are the water runs off either side obviously you've got all the weight of them tiles on that roof so the tendency is that if it's not strapped together across between the two points at the bottom it's going to slip like that the plates are going to slip off the wall and the roof's just going to collapse so it's very important that they're tied from side to side and we quite often put a collar in at the top here which holds that in as well on modern roofs that's probably usually as much as we go to on this one in fact we're putting a post down the middle every two meters um but because we tend to use these six by two joists now um they're a lot a lot um more substantial and they don't tend to sag in the middle like old roofs do so if you were thinking about maybe converting the loft space that you've got in your old house to to have your train set or whatever you want to have in there um you'll probably find that you've got what we call a purlin it runs through about midway so basically that runs through it picks up on every single rafter and then every say four feet there will be a prop or pulling support that comes down onto a spine wall of course if you want to play your train set that's causing you a problem but it's really important that you don't cut them out because that is supporting your you cut them out your roof starts to sag you get leaks the rafters start to fail it might take a long time but it will happen and i suppose snow loading is probably the most extreme isn't it exactly yeah i mean obviously you've got all the weight of the tiles already be it clays or concrete i mean majority of the time it's going to be concrete because a roof would have been replaced over over time but there you had all that snow on top of it as well and then we're talking an extra load of weight there and that that's a bit of an issue isn't it if you take a slate off a roof and you replace it with concrete tiles yeah it's because when a lot of these the victorian properties that were done with slate um obviously slate is fairly lightweight compared to a concrete say redone 49 which was a very popular tile made in 1949. oh nothing many people know that yeah someone told me that yeah were they that was you yeah so but you know that's quite a heavy tile in comparison um you know probably three plus times the weight so then you've added all that extra loading on that that roof then which was never designed to take that amount of weight then you put snow on it then someone cuts the purlins out because they want to play with their train set the next thing you know the roof's in the bedroom yeah and i think even if it just goes a little bit it's very hard to bring them back again it is i mean uh funnily enough about a year or so ago ian and i had a little job of converting an old outhouse it was quite a big outhouse actually it was like a storeroom it used to have a toilet in it but it was separate from the house and we converted into a dog grooming parlor and they'd had the roof on that was it was a pitched roof but it had i don't know what it originally would have had it was it was definitely not concrete tiles um it was probably a 1930s build perhaps a little yeah around about 1930s but whatever it had been replaced with concrete tiles and the joists had sagged like you wouldn't believe i mean they were like bananas and the client didn't want to pay to have it stripped off and redone because they couldn't afford it so in the end what we did is we we built another roof internally underneath it and then supported everything off of that and then strapped the side because it was pushing the walls out and everything we had to strap it all back and everything but yeah i mean and that was only a very small roof so you could imagine on something that's like four or five meters long all that pressure on those joists and they still would only be four by twos but once you remove those supports they're there for a reason so when you say we're tying this roof together at the bottom of the triangle that's just what these things down here yeah so these yeah these are so in the bedroom downstairs this will be the ceiling if this was a loft room this would be the top of the floor but it's tight it's holding this building together it's keeping those two walls we've got this wall plate here and we've got a corresponding one on the wall over the other side so this ceiling joist or floor joist whichever it's going to be that spike down into that fix down nicely into that we've got the raft though is also spiked into that and they're also spiked together as well so all loads of connection points there loads of connection points there and it's all pulled together tightly so there's no chance of that pulling apart yeah you sometimes get people saying oh no we always have to put straps in as well metal straps yeah we still do have to put the electrical straps in they still ask for it um it's usually well we put them on the gable wall and i think that's more for the for the wall uh we have to put lateral um other wall straps down on top of the plate and then down the block work every 1.2 meters some people want like a truss clip don't they yeah we're at the oh the selected strong tie where the actual rafter is joined to the plate with a clip a metal clip rather than in my opinion it's a truss clip so if you're using a truss rafter roof you use a truss clip on this style of roof we do our bird's mouth and we we nail it down it's all spiked together we've got nice tight cuts on it all there's not going to be a problem with that you look at this the main house if we go in there and have a look at their bird's mills they'll be exactly where they were because no one's removed any of the props in there okay another thing we get james is people saying oh you shouldn't you shouldn't just nail a roof you should screw a roof together you know they they think their nails aren't strong enough to do it yeah that's been a debate over the years actually a lot of people have questioned why why you use snails it's an old-fashioned thing nails we've got screws they drive in fast they're nice and strong and tight but the problem with screws is especially in the past is that they're very brittle compared to a nail which is fairly mild steel you can bend it around and it's not going to step whereas often you'll find a screw in the wrong position can easily shear and snap as technology progresses we've been using these ones and they've actually got they've got a bit more giving them and funnily enough we drove one in yesterday in the wrong position had to take it out the head sunk in i couldn't get it out i was trying to snap the back off it just it wouldn't snap it took me ages it kept bending around so the the technology has progressed so uh and even down to these forged fast screws where they think they replace the coach bolt and a lot of building control authorities will allow you to use these instead of bolting through um so these these are great and they also have that slight flexibility in them we're now finding in more and more cases we will always use nails to construct a roof because it makes sense they're flexible and they'll move with the roof you know 99 of the time but now we're now finding we can start using screws in some positions where necessary yeah the great thing is i think yesterday those screws came into their own when you had to pull the thing together didn't you yeah and then you you drove them in and you could see it pulled uh the whole thing tight you're not going to get that with a nail you're just all you're doing now is just driving it and holding it together but we put these in at the top the the ridge was was a bit tipped on one side and cupped on the other because we've got a double ridge plate going in we drove them and it just pulled it straight together both sides and then we went around afterwards with nails as well [Music] looking up yeah yeah it's fine [Music] ian's fitting in on the jack rafters so as the main roof pitches 45 degrees we put the square back on 45 degrees and then we've got the backing which is already set up like the height above play and in the bird's mouth he's set again he's got all these jack rafters his height above plate is obviously the same the main rafters here yeah and in the top cup we've got a 45 degree cut there's a plum cut and then if we lay the saw over on 45 yeah that gives you the perfect case not that angle's not 45 degrees but when you cut through at 45 as you can see it does give you a nice cut it's weird isn't it strange [Music] two bits so you could use for jacks yeah maybe actually not that one then you shoot one now you've got a long one there yeah you got one on the bait on the shaft of there [Music] we need a couple well we cut the long one already right two long ones and then the rest one rest of them are there's only two or three short ones there's a bit here we can use for a short jack i think it's i think would probably be close enough and we've got we doubled up this one which we weren't going to yeah and there's a one screwed on the underside of there on the diagonal yeah i think we'll be all right so when you um when you worked out how much timber you needed james yeah did you do it off the drawing yeah you just took it all off a drawing yeah pretty much and i took it off the drawing but i did add a few as well yeah because i allow for them being twisted and yeah a bit all over the place well for dan cutting them wrong um dude have you noticed how i haven't cut any timbers yet so i can't be playing for curtin any room i'm [Laughter] the very last one the little tibbler beautiful mate so we do it rs acceptable i'm gonna get pg tips to sponsor the next one yeah we wanted yorkshire tea that's what we want anyone can use it so that is the thing it makes it a lot more simpler yeah and i'm now getting brick layers that are buying them really and i can't wait for the chippy to come along and it's a you know a straightforward roof and it just makes it easier for them so i told quite a few like general builders and bricklayers and they're pitching their own ropes if a brickie can use it roger could use it steady on boys you

Channel: Skill Builder

Views: 205,350

Keywords: how to pitch a roof, how to pitch a roof angle, how to pitch a roof uk, roof construction types, roof construction step by step, roof construction details, roofing square how to use uk, roofing square dan, roofing square footage, roofing square explained, roofing square instructions, roofing square how to use, roofing square uk, roofing square measurement, Ultimate Roofing Square, dan cox roofing, dihedral angle

Id: x6DibIf0F78

Length: 35min 32sec (2132 seconds)

Published: Wed Mar 03 2021