crown moulding for vaulted ceiling
Mastermark1
| Posted in Construction Techniques on
i’m installing crown in a cathedral ceiling. the angle is 9 degrees. the spring angle of crown is 38 degrees. i installed inside corners with transitions but i can’t figure outside corner transition pieces. thanx.
Replies
This question came up just a few days ago (and many times before). I don't quite get it yet myself, but take a look here:
http://forums.taunton.com/tp-breaktime/messages?msg=112033.1
yea i saw that post but i'm going to have to go back to school to comprehend that info
OK. Then try this website:
http://www.garymkatz.com/TrimTechniques/cutting_crown_transitions.html
thanx for the site, that's the one i saw yesterday but couldn't find it today. it seems that the angles would not work on the top (ceiling line edge of rake and bottom wall line like an inside corner transition does. hope that makes sense. thank you after reading the article again,it points out that the left angle is an outside corner albeit a slight one so maybe the same math can be applied to make it work
Edited 10/29/2008 6:15 pm ET by Mastermark1
Hi: I visited the Gary Katz site. Seemed pretty good and was clear. I also wanted to install crown on a vault, but its a story and a half and at one point my vault meets a flat ceiling. Everything comes to an itty bitty point! Tough to paint, never mind trim. That being said any ideas?
well, i finally understood the math once i used a line parallel to the ceiling and divided that angle in half. then that angle was set on my chop saw.everything seems to work on inside corners but not on outside corners; that wasn't mentioned in his article . if it requires a pendant on the outside corners due to profile limitations, then you should consider pendants on inside corners for balanceEdited 10/29/2008 5:55 pm ET by Mastermark1
Edited 10/29/2008 5:59 pm ET by Mastermark1
If you're talking about the little wedge-shaped transition blocks, they work on both inside and outside corners. The block is always located on the sloped section, with one end mitered at 1/2 the slope angle, and the other end mitered normally to turn the level corner.Depending on whether you are sloping down or up from level, the block comes to a point on either its top edge or its bottom edge. Either way, the math and logic are the same: You can't miter in two planes at once without changing the profile, so you miter from slope to level, then turn the corner normally.It's actually easier to visualize on an outside corner, because you can cut a scrap nice and long. If you got the slope miter right, your scrap will be floating in the air parallel with the floor. Once you cut it to exact length, though, it will come to a point.AitchKay
i am talking about transition pieces for outside corners on a rake angle made of the exact same crown. are you saying transition blocks?
If you are turning the corner to level at the TOP of a slope, your block will come to a point at its BOTTOM edge.If you are turning the corner to level at the BOTTOM of a slope, your block will come to a point at its TOP edge.Either way, your crown needs to/will be running level when it turns the corner to the level run.AitchKay
once again, are you talking about a transition piece that is a piece of crown moulding or are you talking about a transition block (made from an entirely different piece of non matching profile) thanx
No, it really works with a piece of the exact same profile!Play around with a few scraps, and good luck!Aitchkay
This should help you along:
http://www.josephfusco.org/Articles/Ceiling%20Vaults/Vaulted%20Ceilings%20and%20Crown%20Moulding.html
It's pretty simple and straight forward.
http://joes-stuff1960.blogspot.com/
show me outside corners in your photos of the same transition pieces made from the same crown please
Sorry, I didn't have any photos with that condition :-(.http://www.josephfusco.org
http://joes-stuff1960.blogspot.com/
does that mean it can't be done, that you know of
There's this article by Katz:
http://www.taunton.com/finehomebuilding/how-to/articles/crown-molding-around-cathedral-ceiling.aspx?ac=fp
thanx, i already read it but it doesn't show outside corners. i e mailed him he said it can't be done
What about an outside corner (or an inside corner) without a transition piece:
Octagon Roof Framing and Crown Molding Angles DevelopmentJoe Bartok
Hey, Joe,I'm posting this again because you didn't reply on the last thread. *************************************************Hey, Joe,All of that goes right over my head! Can you add some narrative text to explain what you are trying to accomplish?From one of the pics it looks as though you are changing the spring angle of the level runs to accommodate the rake runs. That can work with very low slopes, but the look starts to deteriorate at about 2/12, IMO.In other pics, I couldn't really tell what was going on... A lot about various different polygons...The traditional way is to grind custom knives and make a stretched-out profile for the rake sections. But that usually isn't worth the expense.AitchKayPS And I know you're in there, Joe, I can see the curtains moving.
Sorry about not replying earlier, I put your question on my "do later" list and but got busy in my little corner of the world and forgot about your post.
A picture truly is worth a thousand words and it's difficult to describe the process of cutting crown as I'm illustrating it with a brief text description. The idea is to think of the two intersecting pieces crown as two roof planes of equal slope meeting at a corner angle or eave angle. This means what I'm calling the "crown slope angle" must be measured with respect to the same plane ... the "reference plane" containing the corner angle. Knowing just the spring angle of the crown is not good enough. What most of the diagrams show are section views to convert the spring angle to the "crown slope angle".
Sim Ayers (SBE Builders) built the model in the link below based on our discussion in the JLC thread I linked to in the other crown thread. Try following the text and diagrams in his web page, and the links. I think he's done a better job of describing the reasoning than I could.Octagon Roof Framing and Crown Molding Angles Development
EDIT ... I just checked out Basswood's most recent post. Have a look at the images he posted (see example below). Another topic Sim and I talked about was the intersection of a post with a vaulted ceiling. He created a web page and calculator but I haven't had any luck finding it.
View Image
Joe Bartok
Edited 11/1/2008 9:22 am ET by JoeBartok
Edited 11/1/2008 9:23 am ET by JoeBartok
Edited 11/1/2008 9:24 am ET by JoeBartok
I should add that it isn't possible to eliminate the transition piece under all conditions. If the slope of the ceiling is too steep we simply run out of room to manouver. And often it's theoretically possible to create the joint but aesthetically it looks like cr@p.Joe Bartok
Thanks, Joe,So your basic theory is to keep the spring angle constant in relation to the CEILING, instead of the wall, as we usually do. Right?And as we all agree, this works/looks best on gentle slopes. With a 12/12 pitch, the ceiling angle exceeds the designed wall spring angle of the crown, so the top piece would actually be leaning BACK into the wall.And the bottom piece would be almost horizontal.With a 45-degree molding, like a simple cove-profile crown, the top piece in the above example would be perfectly flat on the wall, and the bottom piece would be perfectly horizontal.Anyway, I think we’re talking about the same thing now. Thanks for the note.AitchKay
joe thanks for the pictures, definetly insightful, shows how to coincide with different angles,different planes thanks
Wait a minute! WHAT can't be done?Use more words to describe EXACTLY what you're talking about. Or post a picture. I see no problem at all.AitchKay
well just trying to make smooth transition on outside corner from horizontal to rake without using pendant or changing profile. sort of like inside corner approach with slight protruding angle change. i hope that makes sense. i have no pics
No, no, I think I've got where I went wrong!! Mea Culpa!I was visualizing ceilings that turned horizontal at the point where the walls turned the corner. That's the situation that I'd dealt with before, and transition blocks worked perfectly there.But if the sloped ceiling continues up and/or down past the 90-degree turn(s) in the wall, you've got a problem. I’ll bet that’s what you’re talking about, and if so, you're absolutely right.So the problem we’re talking about is similar to what we’d face if we’ve got a chase, or an elevator shaft perhaps, that goes up through the middle of our room, intersecting our sloped ceiling on all four sides. Is that right?The transition blocks allow for perfect outside miters, but at the top, the ceiling continues on up, leaving our crown down below, where it can’t quite reach up to the rising ceiling.The converse happens below, where the ceiling dives down, cutting off the top of the crown.I’m not mocking this up here, but I do have a scrap piece of 3 1/4” crown that I’m staring at. I’m guessing that there would be a 1/2”-5/8” gap at the top of our situation with a 4/12 slope. That’s probably way up in the air, so it could be filled in and painted to match the ceiling, and no one would ever notice. Or, with a steeper slope/ bigger gap, throw in a length of rope light, and run with it for indirect lighting!At the bottom, the ceiling is more likely to be in the 8’ range, right up close to our line of sight. So we’ll need multiple cheats to fix everything down here. No problem, though.First, pull the crown down away from the ceiling for a caulkable gap at the bottom of the rakes. 1/4”? 1/8”? Whatever seems right. You tell me after you’ve mocked it up.Then, plane off the top edge of the level section (1/8”? 1/4”?) Likewise, you tell me what you can get away with. You want to lift that level section so the profiles match at the miters, but you don't want to cut too much off of the top edge of the molding, because that would look weird.So we’ve possibly gained that 1/2” discrepancy already. And every time we have a miter joint, we have an opportunity for a sandable cheat, too. So that transition block gives us two miters where we can lose another 1/16”-1/8” total.If we’re talking 12/12, 14/12, and all of this still doesn’t work, we glue and staple a piece (2 pieces, stepped?) of 1/8” ply to the ceiling to use as a plaster ground to build down the ceiling on the rake side, upstream of the miter, feathering the mud out towards level at the miter line.It's amazing what you can do when you combine a series of cheats!Post us to let us know how it turned out!AitchKayPS Did I finally get it? Sorry if I didn't picture it right for a few posts!
A 9* vault is not very steep, you can easily do outside corners, but the effective spring angle on the horizontal crown run, after you leave the vault, will be 47* This should look fine.
I recently did a bunch of outside corners from rake to eave on a Victorian home with 12/12 (45*) and 10/12 (40*) roof pitches. There the eave crown was at 83* and 78* spring angles.
This is likely similar to what you are talking about. Here is a page from a text on this subject and a couple of pics of what I am describing:
Right, another solution is to ignore the slope, and miter everything at 90 degrees, changing the spring angle to the wall. As you say, 9 degrees shouldn't be much of a problem for most people, but it does look different. Once again, multiple cheats: cheat the miter angle a bit out of square to cheat the spring angle a bit less. Keep your cheat sandable at the miter.The hand is quicker than the eye, right?AitchKay