I have a 1890’s Queen Anne with a bay to install 5-1/4″ Azek crown molding on. I need help with the compound miter angles. Here are the details:
Roof Pitch 10/12 (40*)
fascia (on which crown is installed) perpendicular to roof pitch
Crown spring angle 38*
Bay angles 45* (22-1/2* miters) in plan view.
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Replies
thinking I have a total spring angle of 78* (40+38).
Edited 8/30/2008 7:39 am ET by basswood
The spring angle of 38° refers to the angle between the wall and the crown. When it's 38, the angle between the "ceiling" and the crown MUST be 52. The third angle (unseen) is 90. The angles of any triangle sum to 180.
That means if you change the angle between the wall the the crown (78, for example), you must correspondingly change the angle between the ceiling and the crown (that would make it 12 in this example).
But you probably know all that.
After writing all of that, I went back and re-read your original post. Here's where your question confuses me:
fascia (on which crown is installed) perpendicular to roof pitch
If that's so, isn't it a normal crown molding install? Or are you trying to make the crown sit at 38/52 with respect to plumb/level?
Perhaps I'm overthinking this. I've had a bunch of strange cuts to make on this job like this 12/12 gable crown into a 10/12 roof. And some other crazy angles. I'll get some more pics today.I've never done some of the stuff I'm running into on this job.Thanks Don
Don,The crown was installed on angled, compound mitered, fascia. I had an effective spring angle of 78* and the crown was installed in the position pictured in the lower right off this page.http://www.sbebuilders.com/octagon/crown_exterior_angles.phpThis install involved compound miter angles I have never encountered before. It turns out that I was not overthinking this (though I am prone to that).
I think your logic is right. Effective spring angle of 78 degrees. Here's a site with equations for figuring it out. Need a scientific calculator though.http://home.att.net/~waterfront-woods/Articles/Compoundangles.htmSteve
I jotted those formulas down this morning and bought a $12 scientific calculator at Kmart to help me figure it out.Here is the bay with crown:
Brian,Crown looks great. Glad that link helped. FYI, the calculator on my computer (Mac) has a scientific mode. Don't know if Windows does or not.Steve
Are you cutting the crown on flat, or set in position in the miter saw?
If the latter, I'd just cut the 22-1/2s and fit them in place. Since the roof plane and the fascia, if I understand right, are at right angles to each other, nothing else really matters.
Just pretend the ceiling is sloped.
If you're cutting flat, you need the math tables for the angles. I think Joe Fusco has them at his site, but I've seen them several places.
Hey Bob, similar answers I see. I find that reassuring coming from you.
Hijack alert:
By the way, if I seemed like I wanted to rush off the phone the other day, it's because I had 2 guys working for me that I had to babysit. It was the first time I had more than 1 helper and it was seriously stressful. They got enough work done, but I probably only did about 1/2 as much as I should have.
Don,More thoughts on this... the fascia is angled out at the top (by roof edge) and in at the bottom--as it runs around the bay--so the fascia, itself, has compound miter angles and looks like "crown."What I am doing is like running crown over crown, I think this changes the approach required, but I'll see soon...off to tackle the crown while I have the boom lift rented.
Brian - when we were discussing this, I didn't catch the part about the fascia not being plumb. Is this a backer for the crown or is it poor man's crown and you're adorning it? Was it built like that originally or was the angled fascia added?View Image
It is original angled fascia from the 1890's. During a recent reroof the original crown, in poor condition, was removed.
Maybe you better order up a "boogerin'" video.
Got the boogerin' done today!
Torpedo level and a bevel sq. forget the numbers, just start with scraps, and sight "through it".
Or at least thats how I wind up getting it right. Start fat and work into it.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Or, just start whacking with the power saw on a chunk. If you can't get the right angle on the third try, try one more...it will be perfect. Then, bring that baby to the chopsaw and set the chopsaw up using the chunk as the guide. never fails.
You got it.
I carry a folding pull saw in my bags, it's laser sharp. I can dial it pretty close with that and an eyeball. Then make the final adjustment with the chopsaw, or God Forbid, cut it from the backside with the circsaw. LOL, Yeah, I hack when I have to.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
I'm pretty sure I'd make all those cuts using the powersaw from the back. Maybe not though. In my last years framing, it was easy to set up a chopsaw in the workstation box and leave it set up all night. We'd just leave all the tools in there and cover it with a blue tarp.
I bought a cheapie HF 12" slider for just that kinda stuff..and box gutter relines, we left it on one job most of the winter, up on the scaffold, just stuck a trash can upside down over it if it looked like snow comin.
Grant's guy Dale probably still has it..that was a yr and a half ago, as far as I know, it's still working..99 bucks..LOLSpheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Dale probably still has it
Yup - it's been hooked to a table on the boom lift a few times. View Image
Too funny, that thing was such a POS we almost tossed it a few times. But for general choppin, it would be OK.
New job didn't pan out..looks like I'm staying self employed.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
I used some math combined with the SWAG method. ;o)
Hey, no problem. I thought I might have caught you in the middle of some painting.
Still haven't had the chance to post the pics of the Butt Taper. Soon, tho.
I'll try it with a couple of scrap pieces, but I think the tilted out facia adds a new wrinkle to the standard plan of attack... not sure.I'm gonna got see what I can do with it.
basswood
I'll try it with a couple of scrap pieces,
That's my standard method of attack.
When I start doing the math I just get confused, or get it backwards.
I usually don't cut crown flat on the mitersaw.
I usually set up a jig to hold the crown at the proper angle to the fence.
I don't have a sliding miter saw so I couldn't do that long angle at the bottom where the crown meets the shingles.
Rich
It turns out that the crown was at a 78/12* spring angle--a very low angle and I cut it in position (almost flat on the saw table).My SCMS would not make the long cut where the crown meets the roof either (over 60*), so I cut it with my circular saw with a 45* back bevel.
So this is the job you wee waiting for the lift?
I ca't really see from the pic, since its kinda dark. But if the fascia is 90 deg. to the roof, the crown should be pretty easy to figure out.
Was there crown there originally?
You may just be overthinking the whole thing. I do that myself. Just stop thinking, and start working. You'll figure it out .
You are right, I waited to get a lift for this job, and got jerked around by the rental place. They finally agreed to get me a lift for Monday morning, then Monday they said "the lift is down, needs a part" translation, "We forgot to get a lift moved here from Rochester until you called and asked where the lift is, so it just now being moved here."Got the lift Monday PM (already had to jump on another job--had help lined up for the day). Got started on the crown Tuesday and a half day Wed., then had to work on a bathroom for a couple days (getting an old gent back back in his home from a nursing home).Anyway, this was a big crown job (2-3 stories up and with 6 gable ends, the bay in this thread, and a shed dormer--about 300') and the lift was great.The bay crown did turn out to be an odd spring angle, I have never encountered before.I was replacing old crown, but was not around for the tearoff.Cheers,Brian
I cant figure this stuff out myself. I am working on a shed that has rake crown.
Part of the problem is that the 38 and 52 degree angles on the 10/12 pitch dont work out exact so I am re-cutting etc. AZEK crown so $$$$$$ and we already lost 1 piece to bad cuts.
I assumed it would be tough, but not the brain damage I am dealing with.
Client is great and thrilled so it will all work out but wow!!!
I'll be taking pictures after all is painted for my portfolio!!
Sounds like you are doing fine... I took over this job from a contractor who was nailing up this Azek crown flat on the fascia--NO SPRING ANGLE! And if that weren't bad enough, no mitered outside corners, the crown was just lap-jointed... looked real purty.With the bar set that low, I'm lookin' good to this homeowner LOL. :o)Looking forward to seeing your pics. Here is another one from this job.
Edited 8/31/2008 9:49 am ET by basswood
Brian,
I went back a few weeks ago to a house I had built where the HO had installed crown in the den. They used the blocks in the corners so they would not have to cut any miters. BUT they nailed the crown flat against the wall. It was hard to keep my mouth shut and not laugh but I did it. John
J.R. Lazaro Builders, Inc.
Indianapolis, In.
Hi John,You must have bit your tongue pretty hard. <g>Amazing.I deleted that last pic, in favor of another one, but "Manage Attachments" would not let me add a new photo... here it is
Beautiful house. How much of that have you done?
At this point, I'm just the exterior crown installer. I am going to bid rebuilding the front porch though.I suggested borrowing the same frame and panel detail on the barge boards for the new porch columns. The owners liked that idea, so I just might get the job.
It is nice when some of those "professional" contractors set the bar for you to be a hero when all you are doing is your job they way you would want it done.
I was in a clients home the other week. She ran out of money and had a "friend" help with the crown.
It was upside down. At least they sprung it on the wall correctly though.
Crown, upside down looks kinda crappy.
I was at a million dollar + open house a few years ago ( just looking), and noticed the crown was upside down.
When I said something to DW, she poked me in the ribs.
When I said something to the realtor, he said he'd tell the builder.
Yeah, like I'm expecting him to do anything at that point.
The house was pretty nice, but the crown stood out to me like a sore thumb.
In the not too distant past, I put a crown (I had never seen before, with a complicated profile) in upside down. It was the way the homeowners wanted it installed, so it is all good.I posted pics of that job here... I was all proud of myself...BT'ers posted back... "Uhm, Dude that crown is upside down."Ooops!
I'm half afraid of posting the picts of my crown mold job on the shed I am building for fear we are doing something wrong.
It has more AZEK on it than most homes I have ever built.
Here is that crown installed flat, with lapped corners and upsidedown:
Wow
Not hard to look like the hero after that mess!!
Best thing to do is exactly what Shep and Sphere said. Do a mock-up, and then you'll know for the rest of the job.
My experience on the Victorian houses is that spring angles change from the old to the new anyhow, so you just start over with the new. From the ground outside is not the same visual as in an 8' parlor ceiling.
Sometimes you just have to get rid of the numbers or they will drive you nuts.
"It is original angled fascia from the 1890's. During a recent reroof the original crown, in poor condition, was removed."
Just out of curiosity, what did it look like? The replacement is colonial crown ... but of course 1890s was 'transitional'.
TIA
Jeff
Edited 8/30/2008 11:21 pm ET by Jeff_Clarke
Jeff,The house had both colonial (like the Azek, but 4-1/4" instead of the 5-1/4" used as the replacement) and a unique crown that was the original.If it were up to me, I would have had a copy of the original crown milled. I saved the crown that was torn off and will post a pic. I like the profile... also had an odd spring angle.
Jeff,Here is the original crown:
Basswood, here are links to some info on crown molding installed on compound rake walls, angled ceilings, etc., generally without using transition pieces.
Polygon Rafter Tables ... this turns into a discussion on calculating crown molding angles. The results of this thread:
Compound Rake or Prow Roof Crown Molding Angles ... my online notes and diagrams. One of the links on that page points to:
Development of the 6 Tetrahedrons for Crown Molding Angles Using Plane and Spherical Trigonometry ... this is authored by Sim Ayers. He actually made an effort and took the time to cut the molding to the calculated angles in order to test the math. There are links to other calculators and diagrams at the bottom of his page ... check out the model of the octagon roof.
Joe that is some great stuff! Thank you. I hoped you would see this thread.I enjoy learning to apply more math to my work... had to pick up a new scientific calculator (they sure are inexpensive these days--no excuse not to have one on the job site).The bay crown I installed yesterday ended up with virtually the same spring angle and compound miter angles as the example in the lower right of this page you linked:http://www.sbebuilders.com/octagon/crown_exterior_angles.php
I missed your earlier post, seems like you made out O.K. without the theory but I'm glad your finding the math in the links useful.
That octagon roof was Sim Ayers' creation: he took the time and effort to frame the model and cut the crown molding to test drive the math we were discussing in that JLC thread. I have to say it was a pleasure chatting with another person with a serious interest in applied geometry and math. He hasn't been posting for a while now and I miss his challenging questions and insights.
In a nutshell, when cutting crown molding at strange and weird angles we need to get away from the notion of a spring angle measured with respect to the wall as it is usually defined. The spring angle has to be coverted to what we were calling the "crown slope angle" ... the angles of both intersecting crown measured with respect to the same plane, what we called the "reference plane".
The variables for crown molding relate to the angles in a Hip/Valley roof. The "Crown Slope Angle" corresponds to the "Pitch Angle" of a common rafter, the corner angle on the "Reference Plane" is the equivalent of the corner angle formed by the intersecting eaves in plan view. The Crown Miter Angle is the same calculation as for the Jack Rafter Side Cut Angle, and the Crown Molding Bevel Angle uses the same formula as the Backing Angle.
And now I have to run ... I'm on a public computer and they're shutting down in a few minutes. :)
Joe Bartok
Thank you Joe,Great stuff. I spent 4 days in total, running crown around that Victorian... one of the most challenging trim jobs I've encountered. Mastering the math will help with this kind of job in the future.Cheers,Brian
That's an amazing diagram and description! Five decimal places ..... ;o) Thanks for including the crown profile - definitely what I would call transitional.
Jeff
eta - I've seen lots of interior crown, upside down, in hotels (for some reason)
Edited 9/1/2008 1:48 am ET by Jeff_Clarke
Hotel crown might be installed by commercial, union carps, who do mostly drywall and concrete forms (no offense intended to any union members on this board).
basswood
Hijack alert.
I thought you might enjoy some pics of the crown molding on my turret.
House was built 1890-1900.
I look out my bedroom window every morning and see this #658.
The turret shingles were almost non existant when we bought the house in 1988.
Shingling the turret was the first roof area we did. That led to painting that area because we had the scaffolding in place. It was several years before the paint scheme on the rest of the house caught up with the turret.
I just give thanks that I don't have to rebuild the trim on this turret. Can you imagine having to rebuild the curved soffits?
The top crown mold is a 3 1/2" 1/4 round. The bottom crown is standard crown.
Rich
That is sweet, keep it maintained and you'll save yerself a HUGE headache.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
Rich,That is a fantastic turret! What a great hijack. I am amazed by what those Victorian era carps could do... I feel like a hack on these jobs.The house in this thread was very well crafted. All the 12/12 roofs were dead on when I checked the angles. All the outside corners on the fascia were perfectly square. Wonderful work, better than I see in new construction.
basswood
I am amazed by what those Victorian era carps could do... I feel like a hack on these jobs.
More hijack. I like to show off my house. I put alot of elbow grease into. Luckily the 1960's remodelers didn't get their hands on this one.
It's just another nondescript house in a town of many victorians but it has some nice details.
More pics for you. I have posted some of them before.
I'll post some more in the next post.
Rich
basswood
This stairway makes me feel like a hack.
I stripped it and refinished it. The front entry, stairs, upstairs hallway took us 18 months. With a few breaks in there.
The house is assessed at 138 K but I doubt I could sell it for 100K.
It doesn't have a 3 car garage and a master bath. LOL
Rich
Rich,The ceiling work, rail, and floor are wonderful. What a treat that you get to live there (I know is was a tremendous amount of work to restore).My place is a rather plain colonial revival, built prior to the Victorian period (except for the dance hall). The house that started this thread has these cool twisted corbels, that start in one plane at the top and skew 45* at the bottom.I better get back to office work,Brian
brian
Cool corbels
I have 2 overhangs like that but we have rather plain corbels. Those twisted corbels give the painter a chance to make the house pop.
Have a good day at the office.
Rainy day down here. We were going to roof, but we had to change plans.
Rich
RichRan a kid to school, paid for the lift rental, hit the office and caught up on some bills, invoiced that crown job, called for underground utility locations, made some others calls. I'd actually rather be roofing, than in the office.Now I'm unloading my flat bed tailer (full of debris from a bath tearout) and dropping it off at another job, then doing some punchlist stuff, picking up ladders at the crown job. Goofy day.Later,Brian
brian
Woke up to rain this morning. Canceled the roofing.
Called a inside job. HO started 5 projects, hires us to come in a finish them. I told him only on rainy days. Part of that job we have to set up the miter saw and we can't do that when it's raining cats and dogs.
No go on that job, having vinyl being laid today. Send the boys out to finish trim on a patio door. http://forums.taunton.com/tp-breaktime/messages?msg=108841.1
I do office work. Try to remember how to use Home Design 6.0, to draw up a kitchen and bath that I looked at a week ago. Possible work in Jan. Answer the phone again and again. Talk to the yard about insulation trailer for a job.
Look at a vinyl siding hail replacement job (insurance) we could do that in Nov or Dec.
Take kitchen design ideas to the lumber yard. Line up the roof for tommorrow.
Do the insulation job (attic) in the afternoon.
Crazy day around here too. Only got paid for 1/2 of it.
Rich
Talk to
I liked the rooster in that other thread.I've heard that the average contractor works 9 hrs. a day to be able to bill out 7 hours. That squares with my experience.Crazy gig this is.Good night,Brian