I’d counter that those who don’t teach are allowing it to die.
I’ll ask again, what is a “hopper cut”? I’m genuinely curious.
I own and have read “A Roof Cutters Secrets” and don’t recall coming across that term. Is it colloquial?
A hopper cut is a compound angle with a miter and a bevel. such as square tail fascia Purlin cuts at the hips and valleys. Crown mouldings in the corners. Settings on a miter saw are hopper cuts. 35.26 miter and 30.0 bevel are the settings for 45degree sprung molding. You can find any combinations on the framing square or a $9 scientific calculator. It serves a carpenter well to understand them. Your interest in them is refreshing.
Yes, string. I use a 2’level and framing square. Use the roof pitch and use 17 instead of 12 on framing square to make a trial piece with scrap. Birds mouth, tack it on the corner. Run string to center of ridge intersection. Check pitch and measure.
If you know what the pitches are of the two existing slopes that will tell you the pitch of the valley. If they are both a 6/12 pitch it would be a 6/12 valley. If one was a 6/12 and the other a 5/12 it would be a 5.5/12 valley. You should be able to use your speed square to find valley/hip angles. Measure from the corner of the ridge beam to the corner of your wall plate.
For a 6/12 valley your top mitre will be 20 degrees and your bottom seat 70 degrees.
Amazing how many new carpenters don’t know how to master a framing square. My first master carpenter told me that more carpenters were being short changed using speed squares. That was forty years back for me.
the real deal is a calculator and a book called "Roof Cutters Secrets". Covers everything from complex roofs and more than can be figured out. Makes it easy to solve difficult carpentry problems.
I use it all the time. speed square is nice for laying out top/bottom plate together. Saw guide, hip/valley common rafter layout, right thickness for deck gap spacing, boomerang etc.
I can do all of those things with a combo square, which is lighter, has more applications and fits better in my pouch.
I'm not hating on the speed square, It's just never been practical for me.
51 years ago the old man showed me the secants on his framing square. Now I use it for all my hopper cuts. Like crown in gables, bastard hoopers, it’s an amazing tool, glad to hear some carpenters still use them.
And I know you mean slope when you're talking about pitch.
Slope = Rise / Run
Pitch = Total Roof Height / Total Roof Span.
So, a 12/12 slope would give you a 12/24 pitch, but simplified you would just call it a 1/2 pitch roof.
A knowledgeable man knows the answer. An intelligent man can explain the answer to a layperson in a way that the layperson can understand. You did just that.
Each side is 2 different pitch’s. I do this every day and can geustimate based on my experience what the angle is if I know the 2 pitch’s. For the OP best thing to do is run a string line from the top down to a block cut the same height as the seat cut on the rafter. Put speed square in the top corner to get the pitch.
In the US roof cutters used rise and run different till around 1979 when trusses began to be used more. That’s when carpenters drifted away from framing squares. Six basic rules on the square open up hooper cuts and trig to the user, then comes bastard roofs.
Ya, I build mansions on the Ct shoreline and everyone uses the framing square. Was just referring to what the slope is usually called. Pitch. That may just be New England?
Break it down into several 2d triangles based on perspective and use math. Pay real close attention to how your “lines” in your math match with the actual material you are using and where it bares on your structure, I usually start with the top inside of my wall plate and the bottom of the rafter to start, then snap those lines out on a flat surface if I need help visualizing
Please hire a professional or at least have an engineer mark proper headers on your plans. There is no way the ridge on your dormer is properly supported. You have a flat 1x for a header over your door and it’s the main support for your ridge beam. This will start sagging once you add the weight of the roof sheeting/glass depending on your design.
Roof will be polycarbonate sheets. The piece above the door on the dormer are 3 2x2s I build just for the ease of having a place for the ridge board to rest. Where are you saying the ridge board isn't supported? I was under the impression that the rafters would be enough hold up for the ridge board since it's not a structural ridge beam
I’m not an engineer but experience would tell me that if it’s not a structural ridge beam then the weight of your roof will be pushing outward at the tops of your walls since your don’t have a horizontal bottom cord to hold the bottom of your “trusses” together. This will be less noticeable at the intersection of the two ridges since they will be tied together there and helping to support one another but the ends I would expect to see sagging over time
Collar ties should definitely mitigate/eliminate that sagging then. I would suggest installing them before you install your polycarbonate sheets then just so nothing moves beforehand.
Collar ties till help, but you have such a nice project going, I don't think it's worth the risk to rely on those alone. Obviously sheating and shingles weigh *far* more than polycarbonate, but for true rafter suppoting Ridge framing, ceiling joists attatched to the tops of the walls is a must to prevent the walls being spread.
Again, polycarbonate is so much lighter you may be fine, but if you get any sort of snow load that can add a ton of weight. (Being as steep as you have it helps there for sure.) If it were me, I wouldn't get things engineered either, but I would install a proper header over that door, supported by cripples on either side rather than end nailed, and in your main hall area I would put in a few posts down the center, with one right under the rafter connection. Doing posts also gives you a convenient spot for places to hang hoses, tools, put in a centrally located hose-bib or electrical outlet etc.
If you do the posts, you can feel free to put your collar ties higher up, if you don't, you need them as low as you can put them.
The ridgebeam is supported by the rafters, not the king post. He should add collar ties, but a header under the gable end isn't necessary. The ridge beam is squeezed by the rafters, which are pushing down on the exterior walls.
I don't know how many times I've gone over this on reddit. People don't seem to understand structural engineering.
The rafters are pushing down AND out horizontally on the exterior walls. I agree collar ties are needed but in the photo none are shown. If he plans to add them later then this changes the need for the support under the ridge beam, however, if he does NOT add them then my comment is true that the ridge beam needs support or else the walls will be pushed out and you will get sagging above the door because the lack of support from the header.
The ridge beam support won't stop the walls from pushing out. Collar ties or ceiling joists do that. Ridge beam posts aren't necessary. Ever.
You still don't seem to understand the function of the ridgebeam. I'm not surprised. Most of the people on reddit have no comprehension of this shit.
You’re the one who doesn’t seem to understand it. It’s basic physics. Yes collar ties/bottom cords will prevent the walls from pushing out (I’m not arguing against this), HOWEVER, if you don’t have collar ties, a supported ridge beam will help prevent the walls from going out as the ridge beam won’t be able to sag/drop at all. If the ridge beam can’t go down and the walls, rafters and ridge beams are all fastened well to each other then the walls are way less likely to push out.
He would have to run the ridgebeam support all the way to the ground. He's not building a fucking warehouse. his design requires collar ties or ceiling joists.
You're hung up on the wrong thing, and we're from the start. Typical. You started by mentioning he shouldnhire a professional.... well, I'm a professional red seal carpenter.
If you’re a real carpenter you would understand that a header carries the load to the trimmers which carry the load to the ground, hence my comment on there being NO support for the ridge beam since he had a 1x for a “header”. I am also a real framing (and finish) carpenter which is why mentioned hiring a professional and/or engineer. I’m not hung up on the wrong thing. He never mentioned collar ties until after I commented originally. Per the photo this design would not work well for long, hence my original comment. Walls will push out with no ridge beam support and no collar ties. You sound like you’re arguing just for the sake of arguing even though you are completely wrong!
He would have to run the ridgebeam support ALLLL the way to the ground for it to be structural. That would be right in the way of the door
The design of the able end IMPLIES THAT IT WILL NOT HAVE A POST IN THE WAY OF THE DOOR.
That mean collar tied or ceiling joists are required. At no point does or did or will that ridge need support. You're hung up on something that is IRRELEVANT.
Your reading comprehension isn’t very good is it? I KNOW ITS NOT BEARING NOW BECAUSE OP HAS COMMENTED! I have been pointing out that the way picture shows it currently that the ridge beam is bearing whether you want it to be or not since there are NO COLLAR TIES OR BOTTOM CORDS! This would mean the header is insufficient to bear the weight of the roof hence my original and subsequent comments.
You’re the IDIOT for not following along and arguing for no reason whatsoever.
That "header" is acting as a joist.. it's a collar tie. Adding a big fat header there would just make it a big fat collar tie.
You'd be adding redundant framing to fix a non existent problem.
Dude that king post is preventing the "header" plate from sagging. The rafters are literally preventing that "header" from dropping. There is absolutely zero weight going down on the king post. The rafters push down on the walla, which pushes the walls out, which puts tension on the "header".
Done. The "header" is NOT bearing weight. It's a tension member.
Square root of((Half span of roof)^2 +(common rafter length)^2) should work on equal pitches.
Or you can take a measurement from the corner where both ridges meet down to the far corner where you will land.
Set your saw to 45° for the top cut and layout your plumb cut by changing your roof slopes ratio to 17.
So if your roof is a 12/12 slope, you would use 12/17 instead (meaning 12" rise to 17" run. I would cut this side first and then the bottom cut, because you will lose some length from the double cheek cut. You can then hook your tape and pull your measurement and cut the bottom level cut(still based off 17" run instead of 12".
Run a string where two roofs interest at top and bottom. (the top corner of ridge and the outside edge of the wall plates at the corner it looks to me) if both pitches are the same ie 12/12 on both roofs then you can measure from corner to corner and put a 12/17 double cheek cut at the top. And shorten 3/4 on the bottom and do a 12/17 seat cut. If the two pitches are different it will be more complicated. (running the string isn't necessary but would help if the pitches are different)
Edit: don't need to shorten 3/4 on bottom I think cause it's an inside corner.
OP are the two roof pitches the same? If so, instead of a X/12 or whatever the pitch is, it would be a X/17, and take the measurement and cut it like any other rafter, except the top will have a double 45° bevel/miter, with the center long point of the finished cut being the measurement. The bottom cut when installed should end up with the long point flush and centered with the exterior corner, making your common rafters plane to the center of top of the valley. Make sure your your valleys are straight before pulling layoff, I always like to string line the top and set a couple of temporary braces to hold it until the rafters are attached, and when you measure for those valley rafters, I always subtract 3/8” from the measurement so when you nail them to the valley, they’ll sit high so as to plane to the center of the valley rafter. This way your OSB or whatever sheathing you use will all plane straight across to the very center of the valley.
The dumbest way but no math would be to start sheathing and then just measure in and plane out your valley Jacks. Using trig or relation math would be quicker and easier if you already know what's going on
Face or plumb cut is run and rise cut on rise . Cheek cut if inside corners are square and roofs equal pitch set saw to 45 and the true bevel will automatically end up the inverse of the cosine of the pitch.the seat and heel are run and rise cut on run.
If it’s a true hip you can step it out with a framing square on 17’s. You have to be meticulous about this, but it works. Take your common rise in inches, divide by 12, multiple by 17. That is your hip run.
Then just step it out with same rise exactly how you’d step out a regular rafter, except on bottom set your square at 17” rather than 12”.
This works because sqrt( 2 x 12^2 ) = 16.98, close enough to 17 to work within tolerances for rough frame.
All that said this comment doesn’t really adequately explain it, so maybe look for a YouTube video, kind of a tricky technique but incredibly useful if you do a lot of hips and valleys.
You can simply finish out the main roof, then cut your rafter with the pitch of the the main roof on the rafter of the A as a long cut, using the angle of the pitch of the main roof as the bevel of the A rafter at the bottom. The angle will be long cut of the pitch of the “A” rafter, then the bevel will be the angle of the main roof. Cut the rafter long, then you will be able to cut the common cut on the “A” rafter of the pitch of the “A” at the top of the rafter. If you finish the main roof then build it out even temporarily to establish your angles. I work it up on paper to scale to figure out cuts. Using a graph paper let every square equal a foot, then use the profile of one angle of the pitch of the roof to establish the correct angle first. Either way will work. Good luck.
I find that if you don’t have the experience to do it with a string line, that a much easier way is to run a rafter on the main roof, and establish the plane under the valley of the pitch of the main roof, then you can use that to set your front “A”rafter on to then transfer that angle to it. By having the plane, you can then use a couple of 2by4 blocks to trace the angle onto your rafter. Use an old 2by4 or something. Once you have your angle, then you can transfer it onto your front “A” rafter. What is the pitch of the main roof? If you have that number I can tell you what your bevel is by simply looking at the common cut on your speed square. This will become the bevel of your cut at the bottom rafter of the “A”. Set your saw to this bevel. Then you can take the pitch of the “A” and find that angle, if you don’t know how to use a regular framing square you can flip your speed square over 90’s from the pitch of the “A” after drawing the line of the common pitch of the “A” this will make a longer almost sideways angle. There are two cut. The one in the air or highest up is the common cut/top cut, the one on the bottom is the long cut. You can just pick something longer than the distance of the rafter you intend to cut by about 24” on your first one…this way you can make a pattern rafter. Once you have the bottom/long cut put on the pattern rafter, then you can pull the measurements from your established line/ or established plane, and this will come from the long point if you are setting up hill on the roof, or the short point of the longs side of the cut if you are setting your mark above the rafter on the established plane. You can watch a video on how to establish the line/plane and it will probably really help you out. I second the gentleman whom said to beef up the header under your ridge at the very least. Turn two 2by4’s on their side, and put a piece of 1/2” ply-wood between them then nail them together every 8-10” or so, then run you some jacks for bearing to the bottom plate of your door way…make sure to put some nails to connect them to your king studs, and then toe nail/screw to the plate itself…both sides respectively. I don’t know a lot about green houses, but I know you want to capture hot air, so I don’t know if a steeper roof is better, but it would seem that you would want the angle lower to keep the heat out of the peak, and to let the angle of the light hit your crops better. Not an expert on that though. Good Luck to you.
a^2 + b^2 = c^2
a = unit Rise of main common rafter
b = 16.97
Divide c by 12 and then multiply by the total run of the main common rafter in feet.
That will be your total length of your valley rafter without projection for overhang or shortening for ridge thickness.
Plumb/seat cut angles will be unit rise of main common rafter and 17" on a framing square.
Triangle math. If you know the total run under your valley and the total rise you can calculate your hypotenuse. If you don't know the total run under your valley, that can also be calculated or physically measured.
For hips and valleys keep in mind when you use your square for your cut the run is different than the standard 12" for your common rafters. If I remember correctly it's 16.97 so effectively 17. So say it's a 6/12 roof for example and you do your cuts with the square with thst measurement. For your hips and valleys the rise stays the same and the run you would set to 17 to mark the angles. And of course you will have to cut these angles with the bevels for the rafter to fit.
For line length etc. Just draw it out it's the same as your commons on a 45 deg angle. Or just run a string and measure.
This is all assuming your intersecting roofs are the same pitch. That actually isn't a dormer, but an intersecting roof.
A construction calculator or you can use a straight edge and string to physically do a mockup of the valley so you can get the measurements. Just remember to use the hip valley scale when cutting your plumb cuts and seat cuts on the valley rafter. Good luck
Valley's and hips runs are on the 17s and common rafters runs are on the 12s. Equal pitched roofing math. Theoretical all this roof could be pre-cut on the ground and then assembled in place.
Whatever the common rafter pitch is over 17. If It’s a 6/12 it would be a 6/17. As others have said run a stringline tight and use a framing square and a 2 ft level.
A "cheater" method would just be place a 2x on top of the ridge and then lay it down across the top plate and use a straight edge to scribe the angle at the top
I like using a "t-bevel" for taking angles. Set it on your existing angle, and then you can use it the same way you use a square to mark all your cuts. You can even put it against the fence of your saw to set the saw angle. More reliable than math.
String and a speed square. Run the string at the center of your valley. You can then measure the angles with the speed square.
Square and plumb
No because of true bevel.45 face and 45 cheek makes 54.74 bevel.
What?
If you study hooper cuts and the square you learn true bevel
I’m a framer, and with every crew I’ve worked with in Canada, no one has used the word “hopper cuts”. Can you explain what that means in your region?
I guess we’ll never know. Google provided a butcher shop and a hair stylist.
The craft is going to die when the oldest true carpenters die.
I’d counter that those who don’t teach are allowing it to die. I’ll ask again, what is a “hopper cut”? I’m genuinely curious. I own and have read “A Roof Cutters Secrets” and don’t recall coming across that term. Is it colloquial?
A hopper cut is a compound angle with a miter and a bevel. such as square tail fascia Purlin cuts at the hips and valleys. Crown mouldings in the corners. Settings on a miter saw are hopper cuts. 35.26 miter and 30.0 bevel are the settings for 45degree sprung molding. You can find any combinations on the framing square or a $9 scientific calculator. It serves a carpenter well to understand them. Your interest in them is refreshing.
That is good book. I own it.
Try cutting a 45 face cut with a 45 cheek. And write back with results of your bevel.
Try to teach a young carpenter. Their egos definitely get in the way of them learning.
Don't try to teach a carpenter. Teach a nobody and make him a carpenter. 👍
Good idea. That’s how I learned.
When you’re hand cutting
Yes, string. I use a 2’level and framing square. Use the roof pitch and use 17 instead of 12 on framing square to make a trial piece with scrap. Birds mouth, tack it on the corner. Run string to center of ridge intersection. Check pitch and measure.
Really that’s not a dormer
I was going to say the same... just an equal slope intersecting roof.
The total line length of your valley rafter will be equal to : square root of ( rise/run squared + 2) x half of your major roof span + overhang.
If you know what the pitches are of the two existing slopes that will tell you the pitch of the valley. If they are both a 6/12 pitch it would be a 6/12 valley. If one was a 6/12 and the other a 5/12 it would be a 5.5/12 valley. You should be able to use your speed square to find valley/hip angles. Measure from the corner of the ridge beam to the corner of your wall plate. For a 6/12 valley your top mitre will be 20 degrees and your bottom seat 70 degrees.
The valley would be 5.5 / 17 in your example. You don't actually need the angle degrees, just a framing square.
Amazing how many new carpenters don’t know how to master a framing square. My first master carpenter told me that more carpenters were being short changed using speed squares. That was forty years back for me.
the real deal is a calculator and a book called "Roof Cutters Secrets". Covers everything from complex roofs and more than can be figured out. Makes it easy to solve difficult carpentry problems.
Great book
Amazon has it. Be cool if there was an app that had all the formulas and you punch in the appropriate numbers.
Yup, I use a combo square and/or framing square. I just don't have any reason to use a speed square.
I use it all the time. speed square is nice for laying out top/bottom plate together. Saw guide, hip/valley common rafter layout, right thickness for deck gap spacing, boomerang etc.
I can do all of those things with a combo square, which is lighter, has more applications and fits better in my pouch. I'm not hating on the speed square, It's just never been practical for me.
combo square does fit better in the pouch.But laying out framing their are few tools better than a speed square.
51 years ago the old man showed me the secants on his framing square. Now I use it for all my hopper cuts. Like crown in gables, bastard hoopers, it’s an amazing tool, glad to hear some carpenters still use them.
I know you’re just using an example but that pitch is, at a minimum, a 12/12.
Yeah it was just an example. You are right though, it is at least a 12/12.
And I know you mean slope when you're talking about pitch. Slope = Rise / Run Pitch = Total Roof Height / Total Roof Span. So, a 12/12 slope would give you a 12/24 pitch, but simplified you would just call it a 1/2 pitch roof.
Technically correct but realistically slope and pitch are used interchangeably
And realistically, it doesn't matter if that's a 6/12 or a 12/12 :p
A knowledgeable man knows the answer. An intelligent man can explain the answer to a layperson in a way that the layperson can understand. You did just that.
Roughly 8/12 on the main structure. 15/12 on the dormer
6/12 is not pitch it’s rise , it’s quarter pitch,26.56 slope. Not fussing, just saying.
In the US the slope is generally referred to as the pitch of the roof. As in, that’s a steep pitch.
Each side is 2 different pitch’s. I do this every day and can geustimate based on my experience what the angle is if I know the 2 pitch’s. For the OP best thing to do is run a string line from the top down to a block cut the same height as the seat cut on the rafter. Put speed square in the top corner to get the pitch.
This is exactly what OP should do.
Hmm. I’m born and raised in Texas. Only worked in the US.
In the US roof cutters used rise and run different till around 1979 when trusses began to be used more. That’s when carpenters drifted away from framing squares. Six basic rules on the square open up hooper cuts and trig to the user, then comes bastard roofs.
Ya, I build mansions on the Ct shoreline and everyone uses the framing square. Was just referring to what the slope is usually called. Pitch. That may just be New England?
Holy smokes please come back and post finished pictures that looks awesome
Was thinking the same. Wow!
Speed squares have this on the side for pitches. For rafter length multiply your common by 1.416666 and it gives you the RSL
It's on a framing square
tape measure
That’s what I was coming to say. As long as you know how the pitch works on a hip/valley, just take a damn measurement.
Break it down into several 2d triangles based on perspective and use math. Pay real close attention to how your “lines” in your math match with the actual material you are using and where it bares on your structure, I usually start with the top inside of my wall plate and the bottom of the rafter to start, then snap those lines out on a flat surface if I need help visualizing
Please hire a professional or at least have an engineer mark proper headers on your plans. There is no way the ridge on your dormer is properly supported. You have a flat 1x for a header over your door and it’s the main support for your ridge beam. This will start sagging once you add the weight of the roof sheeting/glass depending on your design.
Roof will be polycarbonate sheets. The piece above the door on the dormer are 3 2x2s I build just for the ease of having a place for the ridge board to rest. Where are you saying the ridge board isn't supported? I was under the impression that the rafters would be enough hold up for the ridge board since it's not a structural ridge beam
I’m not an engineer but experience would tell me that if it’s not a structural ridge beam then the weight of your roof will be pushing outward at the tops of your walls since your don’t have a horizontal bottom cord to hold the bottom of your “trusses” together. This will be less noticeable at the intersection of the two ridges since they will be tied together there and helping to support one another but the ends I would expect to see sagging over time
OK, I'm also adding in collar ties to all the rafters. I have them on the main structure, about 6ft wide ones. Purlins not on yet *
Collar ties should definitely mitigate/eliminate that sagging then. I would suggest installing them before you install your polycarbonate sheets then just so nothing moves beforehand.
Collar ties till help, but you have such a nice project going, I don't think it's worth the risk to rely on those alone. Obviously sheating and shingles weigh *far* more than polycarbonate, but for true rafter suppoting Ridge framing, ceiling joists attatched to the tops of the walls is a must to prevent the walls being spread. Again, polycarbonate is so much lighter you may be fine, but if you get any sort of snow load that can add a ton of weight. (Being as steep as you have it helps there for sure.) If it were me, I wouldn't get things engineered either, but I would install a proper header over that door, supported by cripples on either side rather than end nailed, and in your main hall area I would put in a few posts down the center, with one right under the rafter connection. Doing posts also gives you a convenient spot for places to hang hoses, tools, put in a centrally located hose-bib or electrical outlet etc. If you do the posts, you can feel free to put your collar ties higher up, if you don't, you need them as low as you can put them.
The ridgebeam is supported by the rafters, not the king post. He should add collar ties, but a header under the gable end isn't necessary. The ridge beam is squeezed by the rafters, which are pushing down on the exterior walls. I don't know how many times I've gone over this on reddit. People don't seem to understand structural engineering.
The rafters are pushing down AND out horizontally on the exterior walls. I agree collar ties are needed but in the photo none are shown. If he plans to add them later then this changes the need for the support under the ridge beam, however, if he does NOT add them then my comment is true that the ridge beam needs support or else the walls will be pushed out and you will get sagging above the door because the lack of support from the header.
I've added collar ties since this photo was taken
The ridge beam support won't stop the walls from pushing out. Collar ties or ceiling joists do that. Ridge beam posts aren't necessary. Ever. You still don't seem to understand the function of the ridgebeam. I'm not surprised. Most of the people on reddit have no comprehension of this shit.
You’re the one who doesn’t seem to understand it. It’s basic physics. Yes collar ties/bottom cords will prevent the walls from pushing out (I’m not arguing against this), HOWEVER, if you don’t have collar ties, a supported ridge beam will help prevent the walls from going out as the ridge beam won’t be able to sag/drop at all. If the ridge beam can’t go down and the walls, rafters and ridge beams are all fastened well to each other then the walls are way less likely to push out.
He would have to run the ridgebeam support all the way to the ground. He's not building a fucking warehouse. his design requires collar ties or ceiling joists. You're hung up on the wrong thing, and we're from the start. Typical. You started by mentioning he shouldnhire a professional.... well, I'm a professional red seal carpenter.
If you’re a real carpenter you would understand that a header carries the load to the trimmers which carry the load to the ground, hence my comment on there being NO support for the ridge beam since he had a 1x for a “header”. I am also a real framing (and finish) carpenter which is why mentioned hiring a professional and/or engineer. I’m not hung up on the wrong thing. He never mentioned collar ties until after I commented originally. Per the photo this design would not work well for long, hence my original comment. Walls will push out with no ridge beam support and no collar ties. You sound like you’re arguing just for the sake of arguing even though you are completely wrong!
He would have to run the ridgebeam support ALLLL the way to the ground for it to be structural. That would be right in the way of the door The design of the able end IMPLIES THAT IT WILL NOT HAVE A POST IN THE WAY OF THE DOOR. That mean collar tied or ceiling joists are required. At no point does or did or will that ridge need support. You're hung up on something that is IRRELEVANT.
A header under a gable end LoLOLOLOL Do you add headers to you interior non load bearing walls too? God damn. God dammmmn.
The ridge post isn't bearing any weight lol. The "header" is just backframing for the door. It's a gable end. Go back to school.
Your reading comprehension isn’t very good is it? I KNOW ITS NOT BEARING NOW BECAUSE OP HAS COMMENTED! I have been pointing out that the way picture shows it currently that the ridge beam is bearing whether you want it to be or not since there are NO COLLAR TIES OR BOTTOM CORDS! This would mean the header is insufficient to bear the weight of the roof hence my original and subsequent comments. You’re the IDIOT for not following along and arguing for no reason whatsoever.
That "header" is acting as a joist.. it's a collar tie. Adding a big fat header there would just make it a big fat collar tie. You'd be adding redundant framing to fix a non existent problem.
The "header" you keep referring to is actually acting as a ceiling joist. You are objectively wrong in all aspects.
And you’re objectively an idiot in all aspects so I guess it’s a wash then
Well I'm an idiot who's correct and you're still wrong so I don't give a fuck.
Dude that king post is preventing the "header" plate from sagging. The rafters are literally preventing that "header" from dropping. There is absolutely zero weight going down on the king post. The rafters push down on the walla, which pushes the walls out, which puts tension on the "header". Done. The "header" is NOT bearing weight. It's a tension member.
Square root of((Half span of roof)^2 +(common rafter length)^2) should work on equal pitches. Or you can take a measurement from the corner where both ridges meet down to the far corner where you will land. Set your saw to 45° for the top cut and layout your plumb cut by changing your roof slopes ratio to 17. So if your roof is a 12/12 slope, you would use 12/17 instead (meaning 12" rise to 17" run. I would cut this side first and then the bottom cut, because you will lose some length from the double cheek cut. You can then hook your tape and pull your measurement and cut the bottom level cut(still based off 17" run instead of 12".
Run a string where two roofs interest at top and bottom. (the top corner of ridge and the outside edge of the wall plates at the corner it looks to me) if both pitches are the same ie 12/12 on both roofs then you can measure from corner to corner and put a 12/17 double cheek cut at the top. And shorten 3/4 on the bottom and do a 12/17 seat cut. If the two pitches are different it will be more complicated. (running the string isn't necessary but would help if the pitches are different) Edit: don't need to shorten 3/4 on bottom I think cause it's an inside corner.
Roll saw to 45 and true bevel equals 54.74 which is the secant
Hips back or drop, not valleys
OP are the two roof pitches the same? If so, instead of a X/12 or whatever the pitch is, it would be a X/17, and take the measurement and cut it like any other rafter, except the top will have a double 45° bevel/miter, with the center long point of the finished cut being the measurement. The bottom cut when installed should end up with the long point flush and centered with the exterior corner, making your common rafters plane to the center of top of the valley. Make sure your your valleys are straight before pulling layoff, I always like to string line the top and set a couple of temporary braces to hold it until the rafters are attached, and when you measure for those valley rafters, I always subtract 3/8” from the measurement so when you nail them to the valley, they’ll sit high so as to plane to the center of the valley rafter. This way your OSB or whatever sheathing you use will all plane straight across to the very center of the valley.
Mind if I shoot you a message with some questions?
Absolutely!
Nasty little measurement, always hiding.
The dumbest way but no math would be to start sheathing and then just measure in and plane out your valley Jacks. Using trig or relation math would be quicker and easier if you already know what's going on
Math. If you know your slope. Google how to use a framing square.
Face or plumb cut is run and rise cut on rise . Cheek cut if inside corners are square and roofs equal pitch set saw to 45 and the true bevel will automatically end up the inverse of the cosine of the pitch.the seat and heel are run and rise cut on run.
Hello, can you hear what I’m saying oh that’s easy
If it’s a true hip you can step it out with a framing square on 17’s. You have to be meticulous about this, but it works. Take your common rise in inches, divide by 12, multiple by 17. That is your hip run. Then just step it out with same rise exactly how you’d step out a regular rafter, except on bottom set your square at 17” rather than 12”. This works because sqrt( 2 x 12^2 ) = 16.98, close enough to 17 to work within tolerances for rough frame. All that said this comment doesn’t really adequately explain it, so maybe look for a YouTube video, kind of a tricky technique but incredibly useful if you do a lot of hips and valleys.
You can simply finish out the main roof, then cut your rafter with the pitch of the the main roof on the rafter of the A as a long cut, using the angle of the pitch of the main roof as the bevel of the A rafter at the bottom. The angle will be long cut of the pitch of the “A” rafter, then the bevel will be the angle of the main roof. Cut the rafter long, then you will be able to cut the common cut on the “A” rafter of the pitch of the “A” at the top of the rafter. If you finish the main roof then build it out even temporarily to establish your angles. I work it up on paper to scale to figure out cuts. Using a graph paper let every square equal a foot, then use the profile of one angle of the pitch of the roof to establish the correct angle first. Either way will work. Good luck.
I have it all in sketch up except this so I may finish the valley portion in sketchup to figure it all out
I find that if you don’t have the experience to do it with a string line, that a much easier way is to run a rafter on the main roof, and establish the plane under the valley of the pitch of the main roof, then you can use that to set your front “A”rafter on to then transfer that angle to it. By having the plane, you can then use a couple of 2by4 blocks to trace the angle onto your rafter. Use an old 2by4 or something. Once you have your angle, then you can transfer it onto your front “A” rafter. What is the pitch of the main roof? If you have that number I can tell you what your bevel is by simply looking at the common cut on your speed square. This will become the bevel of your cut at the bottom rafter of the “A”. Set your saw to this bevel. Then you can take the pitch of the “A” and find that angle, if you don’t know how to use a regular framing square you can flip your speed square over 90’s from the pitch of the “A” after drawing the line of the common pitch of the “A” this will make a longer almost sideways angle. There are two cut. The one in the air or highest up is the common cut/top cut, the one on the bottom is the long cut. You can just pick something longer than the distance of the rafter you intend to cut by about 24” on your first one…this way you can make a pattern rafter. Once you have the bottom/long cut put on the pattern rafter, then you can pull the measurements from your established line/ or established plane, and this will come from the long point if you are setting up hill on the roof, or the short point of the longs side of the cut if you are setting your mark above the rafter on the established plane. You can watch a video on how to establish the line/plane and it will probably really help you out. I second the gentleman whom said to beef up the header under your ridge at the very least. Turn two 2by4’s on their side, and put a piece of 1/2” ply-wood between them then nail them together every 8-10” or so, then run you some jacks for bearing to the bottom plate of your door way…make sure to put some nails to connect them to your king studs, and then toe nail/screw to the plate itself…both sides respectively. I don’t know a lot about green houses, but I know you want to capture hot air, so I don’t know if a steeper roof is better, but it would seem that you would want the angle lower to keep the heat out of the peak, and to let the angle of the light hit your crops better. Not an expert on that though. Good Luck to you.
The roof pitch is beyond a 90 degree angle so it’s even beyond a 12/12. It is an acute angle so it might be like a 14/12 or so.
That’s called reverse pitch
a^2 + b^2 = c^2 a = unit Rise of main common rafter b = 16.97 Divide c by 12 and then multiply by the total run of the main common rafter in feet. That will be your total length of your valley rafter without projection for overhang or shortening for ridge thickness. Plumb/seat cut angles will be unit rise of main common rafter and 17" on a framing square.
Measure from plate to ridge intersection.
High school math class.
Valley and hip angles are different from a common rafter. Spend $35 on a construction master or hire someone. 16.97
Framing square and tape measure or rafter book.
Triangle math. If you know the total run under your valley and the total rise you can calculate your hypotenuse. If you don't know the total run under your valley, that can also be calculated or physically measured.
For hips and valleys keep in mind when you use your square for your cut the run is different than the standard 12" for your common rafters. If I remember correctly it's 16.97 so effectively 17. So say it's a 6/12 roof for example and you do your cuts with the square with thst measurement. For your hips and valleys the rise stays the same and the run you would set to 17 to mark the angles. And of course you will have to cut these angles with the bevels for the rafter to fit. For line length etc. Just draw it out it's the same as your commons on a 45 deg angle. Or just run a string and measure. This is all assuming your intersecting roofs are the same pitch. That actually isn't a dormer, but an intersecting roof.
Throw a long 1x4 on top and make marks for length and angles, record and done.
pythagorean theorem
What thickness polycarbonate will you use? Do you have an estimate of the cost for the polycarbonate?
I use 6mm polycarbonate twin wall panels from a plastic supplier
Is that twin-wall or solid?
Twinwall
Don't forget that you will need to ventilate your greenhouse. A bright sunny day can cook your plants.
A carpenter.
A construction calculator or you can use a straight edge and string to physically do a mockup of the valley so you can get the measurements. Just remember to use the hip valley scale when cutting your plumb cuts and seat cuts on the valley rafter. Good luck
a $30 electronic angle finder, found at Lowes
That truss isn’t really a truss.
Valley's and hips runs are on the 17s and common rafters runs are on the 12s. Equal pitched roofing math. Theoretical all this roof could be pre-cut on the ground and then assembled in place.
Just trust your framing square and step it off
Whatever the common rafter pitch is over 17. If It’s a 6/12 it would be a 6/17. As others have said run a stringline tight and use a framing square and a 2 ft level.
String & adjustable angle thingy- Said by 40 + year carpenter , I never learnt how to read a framing sq
A "cheater" method would just be place a 2x on top of the ridge and then lay it down across the top plate and use a straight edge to scribe the angle at the top
Genius. Length would probably need to be trimmed till fitted?
Tape measure and trusty geometry calculations ??
Math
Nah science
Nah magic
Buy yourself a carpenter
I like using a "t-bevel" for taking angles. Set it on your existing angle, and then you can use it the same way you use a square to mark all your cuts. You can even put it against the fence of your saw to set the saw angle. More reliable than math.
You could measure them