*
I have a deck that i want to enclose into a screened area so i will have to put a roof on it, the deck is strong enough to handle the loads that this roof will create. First let me start by giving you guys all the information you should need to handle this question. My deck is 12’x 22′-6″ (The 22′-6″ runs paralell to the house) and the two outside corners of the deck are at a 45 degree angle witch are only 2′-10″ in lenght. Pretty much your standard deck. The roof i want to frame will be attaching to the outside wall of the house because it will land between the 1st and 2nd floor of my house. Most people would just put a simple shed roof on and leave it at that. but i think that looks like an amature did it, so i want to put a hip roof on it. Now im not a pro, but i know how to cut rafters for most commom roofs. So enough talk heres the question, being that my wall framing will follow the perimiter of my deck witch will have two 45 degree outside corners on it, and my birds mouth on my hip rafters will land in the center of the 45 degree section of my walls i have framed, do you treat that section as if it were an octagon and use a run of 13″ or do you use the normal run of 17″ for cutting hips?, and if you do use a run of 13″ will that 13″ only apply to the two hip rafters and the jack rafters, and then go back to standard framing for the rest of the rafters? There will only be two common rafters they will be against the house the two hips will run from the 45 degree outside corners of the wall to the common rafters against the house. oh yeah i forgot there will be one more common rafter in the center of the span. I also want the bottoms of my rafters to plane so i can finish them. thanks to any of you that can help.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Fine Homebuilding's editorial director has some fun news to share.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
*
O.K. McGrath- If you are framing a standard hip you will need to stick to the 17" you refer to. You will need to raise the plate height on the 45 degree walls to meet the hip rafter.
If you choose to keep the wall height consistent you will need to drop the hips to meet it. This creates unequal roof pitches between sides. There are some good articles in previous FHB to explain how to handle the framing.
You may need to rip an inverted "v" in the hip rafter to "plane" your ceiling
*mc,You would have received more feedback sooner if the details of your problem were more clear.I've read your post several times, and still am not certain of what you are attempting to accomplish.If the span is 22' 6" then the RUN of the common rafters that will be nailed to the existing wall will be 22' 6" / 2 = 11' 3" - 3/4" = 11' 2 1/4" ( assuming that the short ridge board that you will need is 1 1/2" thick. )The common rafter coming from the 22' 6" wall at its center point will have the SAME RUN = 11" 2 1/4".This means that you will have a ridge board = 12' - 11' 2 1/4" = 9 3/4" in length, if you wish to have a SINGLE PITCH ROOF ON ALL SIDES ( which I assume you do )If you allow the common rafter from the 22' 6" wall to run all the way to the joinery of the common rafters that are nailed to the existing wall, it will have MORE RUN ( 12' ), and you will enter the world of "double pitch roof framing", an experience that you may not enjoy.The hip rafters that will cross the center points of the short 45 degree walls will have to be "propted up " to a certain height in order to plane in with the common and jack rafters. In addition, You will have to "drop" the hip rafters slightly in order for them to plane in properly, the amount, depending on the roof pitch, which you haven't mentioned.The hip rafters would be cut at 17 on the body of the framing square. All common and jack rafters would be cut at 12 on the body, the unit rise being the same for both.I would encourage you to clarify the problem that you present to us, so that those of us wishing to respond can offer our suggestions, and advice. If I am reading your post accurately, the walls running perpendicular to the house would be 10' long, then turn at a 45 degree angle for 2' 10", to join a wall parallel to the house wall that is 18' 6" long.Check these measurements, and then post a response please, along with the desired roof pitch, and forgive me if I have totally misinterpreted your post.Just trying to help.Ken
*Ken I think you nailed it I agree with your figures, but,it'3am and I did it in my head.jim
*Ken,your figures are correct. I believe the "13" that Mc. refers to corresponds to the "length common rafters per foot run" of a 5 pitch.I couldn't figure where the "13" was coming from 'till I checked a framing square.Your thought on clearer info is dead on. You excercised much more patience answering the post than I could muster.
*Doug, Jim at great white, Mad Dog,Thanks for the feedback. Now, if mcgrath will come back and clarify the wall dimensions, we can give him further advice.There is something very interesting about his roof framing problem. If you 45 degree the outside corners so that the measurement of the plate at the outside building line is 2' 10", as in mcgrath's case, then the RUN of the hip rafter is REDUCED by 17 inches ( from its normal corner if the plates were extended to meet at 90 degrees). And since the hip rafter is cut on the unit rise divided by 17, the block measurement needed to prop up the hip rafter at the center of the 45 degree wall would be equal to the UNIT RISE of the roof ( assuming that you cut the birdsmouth on the hip with the same plumb measurement remaining above the heel cut). For example, if the roof pitch were 8/12, you would need an 8 inch block to prop up the hip. If the roof pitch were 12/12, you would need a 12" block to prop up the hip. You would still have to "drop the hip" appropriately, for the desired roof pitch, but that's no biggie. You could do it in the standard way, or as an alternative in this situation, simply deduct it from the height of the block while leaving the plumb measurement on the hip above the heel cut the same as for the common and jack rafters.Kind of cute.The math?2' 10" = 34 " / square root of 2 = 24.04" ( offset from true corner if plates were extended to meet at typical 90 degree corner)24.04" / square root of 2 = 17"
*Ken,I noticed in your first post you mentioned a short ridge board. Is this in effect, a ledger board attached to the wall? Or are you anticipating a hip roof with a flat top? I got confused there.
*Ken- will you balance my checkbook? You are most mathematically impressive! I can do the math, it just didn't occur to me to do it. Will you be my trig lifeline? Final answer?!
*
ok,guys im back. The pitch I want to put on my roof is a 12/12. Just to clarify how I came up with that 13" run . I was told by an old time framer years ago that you frame eight sided building with a run of 13" instead of 17" for your standard hips,now i thought the same princible would apply to the 45 degree sections of this roof let me give you an example of how he showed me. EXAMPLE: Take a peice of plywood with a square edge (doesnt have to be afull sheet, just a small peice). Next draw a 22 1/2 degree angled line on the plywood from the edge, (you can let it run long it doesnt matter)Next draw a 12" vertical line from the same edge until it intersects with the 22 1/2 degree angle at the 12" mark. Now measure the 22 1/2 degree angle from the intersection point, it will be 13". Bear with me this makes sense. Now draw a 13" horizontal line and a 12" vertical line at 90 degrees to each other,( This 12" represents the rise) and connect those two lines, now measure that angled line, it will be about 17-3/4". Now take your span and divide by 2 ,in my case 22'-6" divided by 2 is 11'-3", now times 11'-3"x 17-3/4"= 16'-5 3/4" if i did the math right. now adjust for your ridge deductions and overhang and thats the rafter length. i was looking at those 45 degree outside corners just like they were the corners of an octagon what do you think. Thanks guys
*
over to you kenny...
*McGrath, the run of 13" is used as the unit measure to frame octogon roof hip rafters.But you are not friming an octogon. You are simply framing a hip roof. You correctly stated that the hip will bisect the diagonal portion of your deck wall. But you imply that you intend to keep the roofline square, or at least that is what I am sensing.If you decided that you did not want a rectangular fascia line, you would be creating a hip at each corner. The alternative would be an unequal pitch situation, resembeling a dutch hip.So, to answer your questions, you will need to decide.Is the fascia to remain level, around the entire perimeter?Is their to be an unequal pitch roof?Is there only going to be three plains?Are you gabling the little diagonal corners?Questions, questions!Ken's first approach seems the simplest, and cleanest looking.blue
*mcgrath,As your old time framer pointed out, when cutting the hip rafters for a regular octagon, the correct settings using a framing square are the unit rise on the tongue, and 13" on the body. For an octagon with common rafters cut at 12/12, you would cut the hips for the octagon at 12/13.But ask yourself this question: Are your hip rafters running at a 45 degree angle with respect to the main walls, or are they running at a 22 1/2 degree angle with respect to the main walls?From what I am reading in your posts, it appears that you are planning to put a single hip at the center of each 2' 10", 45 degree wall. If this is true, then these two hips will run at 45 degrees with respect to the main walls of the frame , and hence they would be cut at 12/17, The common and jack rafters being cut at 12/12.Once again, please clarify. Also, you may want to read what I had to say about the short ridgeboard that you would need if you wish the hips to run at 45 degrees.
*seems like mc is trying to stretch an octagon or imbed two short triangle roof sections in his hip lines above the clipped corners of his deck....Another solution that I think would be simpler and still be appealling visually would be to just build the roof as a rectangle...with entries at the clipped corners...This would make a little roof section above for those that are entering...Great math and analysis Ken.near the stream,aj
*mcgrath,
View Image © 1999-2000"Whenever, therefore, people are deceived and form opinions wide of the truth, it is clear that the error has slid into their minds through the medium of certain resemblance's to that truth." Socrates
*
I think im going to take Joes advice and put a less er pitch on this roof, the rest of the house is 12/12 so i thought i would keep it the same, but i guess it would be a little much for this size deck. I called that old time framer today and asked him what he thought,and he said he would use a total of 4 hips an this roof, he would put hips on those 45 degree outside corners with a common rafter in the middle of the 45 degree section, he said that section of roof would be framed in a pie shape with a common rafter running down the center of the pie. So i guess it would look like a slice of pie,sliced in half verticaly. He called them bastard hips because they will be running on a 22 1/2 degree angle and intersecting into common rafters, and that they would sit a little lower at the ridge. He told me that the common rafters on each side of the bastard hips will be cut with the 45 degree bevels on each side of the plumb cut. The only trick is he said is that i would have to cut those bastard hips on a 67 1/2 degree angle. As for one of Devils questions, i guess i would like the facisa to be on a 45 degree angle. I guess i was looking at it wrong in my first post. I just want to thank all you guys for all your input on this question its nice to know you can get good advice when you need it from all you carpenters. Hey Ken i wish i sat next to you in math class. Thanks again MC
*
mcgrath,
I hope you have a little time before you begin this project. Some of the input you are receiving is correct, but some of it may not be, at least as I am interpreting it from your posts.
Over the weekend, I'll try to post a few drawings of your roof frame, along with explanations for slopes, plumb cuts, etc, which should answer your questions, as well as others. There are several options.
It's possible to frame ALL sections of the roof with the SAME PITCH, using 2 or 4 hips, or, you may opt to enter the world of double pitch roof framing, wether you use 2 hips or 4.
Some additional questions.
Will the rafters be exposed from below?
Any plans for ceiling joists? Or collar tying at a certain level?
*Option A
*mcgrath,This is the first of several roof plans that I will post that COULD be used to frame the roof that you wish.I'll refer to it as Option ANotice the short 9 3/4" ridge board at the wall. Without this short ridge board, the single common rafter that runs from the long wall parallel to the house would have MORE RUN ( 12' ) than the common rafters that will be nailed to the existing house ( 11'3" to the center )This would result in a double pitch roof situation, the pitch of the roof section containing the single common rafter having LESS SLOPE that the two side roofs. The short ridge board reduces the run of the single common rafter to 11' 2 1/4", exactly the same as for the common rafters nailed to the house. It also permits the hip rafters to run at a true 45 degree angle and the jack rafters to match up on the hip rafters directly opposite each other as shown.In addition, the over hang of the roof can be kept consistent and all jack rafters can be cut with a 45 degree bevel using a circular saw. All of the common and jack rafters would be cut at 12/12 ( if you keep that as your pitch) the two hips would be cut at 12/17. Refer to my earlier post as to how to raise the hip up to plane with the common and jack rafters as it passes over the center of the small 45 degree walls.The fascia will all be at the same level also.Later today, ( or perhaps in the morning, when I recover from drinking too much on St. Patty's Day ) I'll post another roof plan with 4 octagon type hips and discuus some of the problems associated with it.
*Happy St. Patrick's Day to All,Okay. Here's option "B", as promised.Notice that the 9 3/4" ridge board is still hanging out. This allows the three "main sections" of the roof to remain at the same pitch, whether it be 12/ 12 or whatever, since the common rafters all have the same rise and run. ( 11' 2 1/4" run for mcgrath's deck. )Also notice that there are 5 distinct roof sections in option B, as opposed to 3 in option A.Because of the manner in which the 5 sections are framed, it is possible to keep the roof pitch of each section the same ( 12/12 as shown, but any roof pitch would work )The fascia follows the same path as the walls, turning when the walls turn, and remains level around the perimeter of the roof, and the overhang remains consistent.The pie shaped section of roof that occurs at each 45 degree wall is simply one of the sections of an octagon, each of whose sides is equal to the length of the plate, 2' 10" in mcgrath's situation. ( See diagram below, left )The 12/17 hip rafter shown in option A, no longer runs to the plate ( where it would need to be propted up to plane in with the jack rafters ). Rather, a short common rafter at the center of the 2' 10" wall ( which sits directly on the wall BTW ) intersects it as shown in the diagram below, right.All of the common and jack rafters in this roof are cut at 12/12. The longer hip rafters, which run at 45 degrees to the wall plates, as in option A, are still cut at 12/17, and the short "octagon hips are cut at 12/13, since they run at a 22 1/2/ 67 1/2 degree angle with respect to the plates. I'll post some options of how to make the cuts at this joinery over the weekend.I've got a lot more to add to this, but it is St.Patrick's Day and I've already enjoyed 3 "greenies", so maybe tomorrow would be a better choice to continue.Have a Happy, and may all your light bulbs remain tightly screwed. ( North of the Equator )Ken
*
Ken,
Thanks for the diagrams. Looking at option B, that 12/12 common that is attached to the 12/17 hip are these going to plane on the bottoms? i wanted to put 1x3 v-groove cedar on the bottoms.
*
mcgrath,
They COULD plane in if you took the time to do so.
What exactly are you attemtimg to accomplish here?
I asked you about ceiling joists; collar ties, no response. All of a sudden you are now talking about 1x3 v-groove cedar. Vaulted ceiling???? All the way???
Take the time to explain exactly what you wish to build. Define what it is you require help with. Give a clear explanation of exactly what areas you need assistance with.
We are here to help, but we are not mind readers.
Ken Drake
*
Ken, the cedar is my wifes idea, come to think of it this whole project is my wifes idea, they think its just 1,2,3 and its done,Im sorry if im not as clear on my ideas but when i figure out how to read my wifes mind, ill let all you guys know how its done. it would be alot easier to finish the bottoms if i just put in ceiling joists in. this whole thing is turning into more then it thought it would be. As for the collar ties i was going to add a few. Ill try to get more refined information soon,
Thanks MC
*
MC,
The cedar sounds like a nice idea, and there are several options.
1) flat ceiling at plate level
2) vaulted ceiling all the way to ridge
3) partially vaulted ceiling
If your wife has her mind set on some sort of vaulted effect, I would suggest the partially vaulted effect for several reasons.
If you look at the roof framing plan that I call option B, you'll notice that the octagon hips intersect with the regular 12/17 hip approximately one-third of the way up to the ridge ( as measured on a common rafter). This is as high as you would want to go for the collar ties to be effective in preventing your outside wall beams from spreading over time. Generally speaking, it is recommended that collar ties used for this purpose should be installed in the bottom one-third of the rafters. At least that has always been my understanding.
This would create an intesting effect from below, as the pie shaped octagon sections would be visible and vaulted, but above that level, the ceiling would be flat, from which you could hang ceiling fans, potted plants, recessed lights etc, easily hiding the wires.
I would start by running as many of these collar ties from the rafters on the long outside wall back to the house and secure them well to prevent the outside wall from spreading. You would probably be able to collar tie the center common and about 4 of the jack rafters on each side of it in this manner, before the 12/17 hips interfere. At that point, you would begin running them perpendicular to your last collar tie (ceiling joist) out to the rafters on the side walls.
After all of the ties (joists) are in place, I would connect everything be nailing flat 2x4's as shown in the attachment, to further prevent spreading.
From your last post, it appears that you like the roof framing plan B more than A. If so, let me know the roof pitch that you have settled on and I'll help you with the cuts, bevels, and joinery if you'd like.
Also, you probably could get away with using 2x6's for rafters 16" on center, but 2x8's might be a better choice. Let me know, as this information is necessary to determine how to bevel the octagon hips, if you wish.
You might also mention how much overhang you plan on for the rafter tails as well as the size of the fascia you intend to use.
*
I have a deck that i want to enclose into a screened area so i will have to put a roof on it, the deck is strong enough to handle the loads that this roof will create. First let me start by giving you guys all the information you should need to handle this question. My deck is 12'x 22'-6" (The 22'-6" runs paralell to the house) and the two outside corners of the deck are at a 45 degree angle witch are only 2'-10" in lenght. Pretty much your standard deck. The roof i want to frame will be attaching to the outside wall of the house because it will land between the 1st and 2nd floor of my house. Most people would just put a simple shed roof on and leave it at that. but i think that looks like an amature did it, so i want to put a hip roof on it. Now im not a pro, but i know how to cut rafters for most commom roofs. So enough talk heres the question, being that my wall framing will follow the perimiter of my deck witch will have two 45 degree outside corners on it, and my birds mouth on my hip rafters will land in the center of the 45 degree section of my walls i have framed, do you treat that section as if it were an octagon and use a run of 13" or do you use the normal run of 17" for cutting hips?, and if you do use a run of 13" will that 13" only apply to the two hip rafters and the jack rafters, and then go back to standard framing for the rest of the rafters? There will only be two common rafters they will be against the house the two hips will run from the 45 degree outside corners of the wall to the common rafters against the house. oh yeah i forgot there will be one more common rafter in the center of the span. I also want the bottoms of my rafters to plane so i can finish them. thanks to any of you that can help.