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we’re remodeling a 1910 bungalow and so far it’s gone pretty well. But now we’re trying to cut and hang the crown moulding. For a couple of people who had a difficult time passing college algebra, it’s been an nightmare trying to determine and cut the proper angles for the corners. Is there a simple formula to help in this process?
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No there is not.
There are variables such as rooms out of square, what type of crown molding etc... which affect every job. You may be better off hiring a trim carpenter for the small job or you might spend more time and money trying to do it yourself.
Pete Draganic
*Donna take Pete's advice and hire a trim man for what I consider a small job . I'm assuming you are installing a 1 piece crown molding . No amount of math skills will replace the knowledge someone has gained from installing it a few hundred times . You will end up wasting alot of material and end up with a bad job . Watch the trim guy and see how easy he makes it look . But don't be fooled he has already made the 10 or 20 mistakes you are making . Good luck
*DonnaKay, If I told you to cut it upside-down and backwards would that make any sense to you? Also, would you understand that you need to cope the corners if the room is out of square? ( almost all rooms are out of square. ) It really isn't that easy. Pete's right. A good trim carpenter can save you lots of frustration. Not to mention all the moulding you will have to throw away because of mis-cuts. I wouldn't suggest do-it-yourself finish carpentry. Ed.
*Or if you really want the satisfaction of doing it yourself, there are 2 or 3 good articles in Taunton's finish carpentry book. They got me through. And I dig them out when I do some more crown a year later and can't remember how I did it.I've found it useful to mock up an inside and an outside corner with scrap to show me how the cut is supposed to fall on the molding.
*Dear DonnaKay: IF you decide to DYI, first review any pre-nuptial agreements, then approach the project with a balanced sense of patience and humor. Few projects can endanger a marriage like running crown for the first time.The earlier posters have given you sound advice. For some "formulas" for the algebraically challenged, check the Delta website. Most likely you'll have 52/38 degree molding to work with.Look out for out-of-square inside and outside corners and uneven wall/ceiling planes. If the crown is to be stained, shadows will hide a lot. If it's to be painted, careful caulking can help a lot.Please preserve those architectural features of your old bungalow, and resist the short-cuts which lead to remuddling.Good luck, Steve
*Donna, when putting crown to the wall make sure it sits correctly to ceiling and wall, at proper angle. If not, inside corners won't seat right and making the cuts ,45's or copes, will be impossible for you.Vince
*Donna, Hire a GOOD Trim Carpenter. One who copes all inside corners and specifically in the proper direction to hide gaps. If the carpenter doesn't know what I mean...take a pass. Be cautious of the trim articles, the last one I read, caused me to write a scathing review.L
*If it is paint-grade work, cut a couple of 1 foot sections with inside and outside miters to give you something to quickly assess the squareness of a corner. I starting using an adjustable protractor to get a precise measurement and found things went a lot quicker. Cut the molding flipped upside down, as if the saw table were the ceiling. I assume you are using a power miter saw? Did you do the rest of the trim yourself?Even with paint and caulk, it will be tough to do a sharp-looking job in an old house with wavy walls and ceiling. Crown doesn't bend so easy. If you are picky you'll end up doing what I did -- pulling down the first try and starting over. But if this is a budget issue, hey...Trying to do a stain-grade job first off will drive you nuts and waste a lot of high-quality clear material.Writing from the asylum, when they let me, ad
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DonnaKay Smith,
Do you have a power miter saw with a high fence?
Louis
*donna, you can call me if you want. Ive never done crown but I think with a little patience and a circular saw..I might be able to get the job done.
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Ditto on the finish carpenter. Donna, even for the most experienced trim carpenter, crown molding is one of the toughest jobs in the business. And unless you do it regularly, it is a real pain in the hindquarters. But if you must do it yourself, here's a couple tips (after 25 years of finish work) I use:
1. On an outside corner, cut it long, and nibble it down so it is perfect. Use a scrap for the other outside corner so you know when you've reached the center of the corner. Expect to cut it 10 times. Better 10 times rather than a too short worthless piece of expensive hardwood crown.
2. Use chalk lines to keep crown straight and aligned.
3. Use triangle blocking nailed between studs to align and keep the crown against the wall. I try to cover about 60% of the wall with 2-3 blocks, and make them out of nice soft 2x4 material that mirrors the back of the crown. I run it off my table saw, and glue and nail the blocking to the wall. Crown is easier to nail to this stupid blocking, rather to to fight the crown, and figure where the heck to nail it.
4. On inside corners, cope the joint.
5.. Buy a very good mitre saw, with a nice high fence, and dead accurate set up. I often use an auxilary fence with a piece of that same stupid triangle blocking attached to it, so my saw set up is the same as the wall.
6. I use a couple Werner Class 1 ladders and a 2x12 as a poor man's scafolding, so two people can hold and nail a long piece of crown. If it is over 12 feet, consider a third person, or another piece of blocking under your chalk line to hold up the crown.
7. Use an air nailer. It is impossible to hold and fight a piece of 12' crown, align it, and then whack 5-6 times and expect it to stay in place. With an air nailer, one pull sets your crown into that stupid blocking.
8. If hand nail you must, pre-drill your holes, and only a couple whacks should set the crown into that same soft blocking.
Hope this helps.
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If you have the right saw I will teach you in a step by step process that is fairly easy to follow. Just let me know!
Louis
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Donna,
Joseph Fusco
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There is a way to cheat, which we used to do occasionally when I was working in the movie set biz and we wanted to be able to disassemble stuff. Build the crown into a square 1/2 box (i.e two pieces to go against cieling and wall.) You can rout a nice little detail on the box edges to beef up your profile. Then (assuming you have access to a big enough chopsaw) you can just cut it and cope it like a big hunk of regular molding.
You are probably better off hiring someone...
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Donna,
Here's the Delta website:
Delta Woodworking
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Just curious: (from a real novice in the trim work world, but with one nightmare behind me) Can you use those blocks like you see in old houses in the corners of baseboard, so that the pieces of crown would just be square cut and butted up against the blocks. The blocks could be shaped or routed (sorta like corbels) to dress up the corners and simplify the job at the same time. Thoughts? Kay
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Backer blocking is a must. I like to rip it out of spruce 2x stock. I have the formula and a $10.00 scientific calculator to input it into, but it would be too confusing to post it. The Delta site should give you all the info you need.
Having said that...
I recommend that you cut two 3 or 4 foot pieces and using the Delta chart mock up each corner one at a time making careful notes. you can use the same scraps for each corner. Nothing beats imperical data.
Keep the angle of the crown to the wall consistent. use chalklines or a temporary ledger.
If it's a very wide crown hog out the back of the inside copes with a jigsaw.(Wish I had that Collins coping foot).
Good luck. There are few things more satisfying then finishing a crown molding job and doing it well.
*Hey Dan, You don't really use a chart do you?L
*I guess you could! But the corners are where the carpenter gets to show off. Also, the corners are what really show off the profile to its best advantage.
*hire a trim Carpenter its not worth the time and money not to I do crown all the time and hate it there is no easy way but to cope and or hope for the the best. However tauton's trim and finish carpentry has some good advise. Hey lawrence can I get my book back??
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Donna;
There is no doubt regarding the trouble a person can get into in doing a molding around the ceiling area i.e. Crown Molding. Many have tried and many have failed and this includes those so mechanically incline as to even take up trim carpentry as a trade.
To some it is a piece of cake or like a walk in the park to do. I personally have a blast with each successful joint and in having a minimum of failed cuts. I was fortunate regarding how long it took to figure out a ‘system’ to cutting it successfully and having a bare minimum of failures or re-cuts. After all a bid job means time is money. I didn’t have the benefit of the Internet but fortunately you do and with plenty of views.
There really isn’t a truly good book to which I can point for showing someone how to do a very tight joint. That is something that is learned by seeing and doing. However it is possible to explain with words to some degree to those who have some experience and it appears you must or you wouldn’t be attempting this project. I say “Bully for you!” However I can only hope this discretion doesn’t bore you too much.
I have a few ‘tricks’ that I personally use to get my inside and outside miters so they are tight and done with a minimum of re-cuts;
b The Saw
The size of the saw and its fence are very important. The fence and cutting blade should be large enough to allow the Crown Molding to set as if it is on the ceiling while being cut. The bed is the ceiling and the fence is the wall. Even with a larger fence I add a back fence to the existing fence that can be precut for each cut outside miter cut being made, i.e. a scrape piece of wood which can be cut to the angle I’ll need the finished piece to be cut. It is made tall enough to accommodate the molding lying as it would at the ceiling. I will either rip it to the height of where the bottom of the crown will always rest on the wall or make a line at that length. I will have one for the right side and one for the left side of the saws fencing and prefer to use MDF material because of how clean an edge it has after being cut. Not to mention how flat it is too. It is precut, just a little, for each miter and then the material is set on the base and up the fence as it will be on the wall. I use the extra fence mainly for the outside corner cuts so they can be as accurate on the first cut as possible. It is possible to make the back of the extra fencing sticky by using a little spray on contact cement and letting it dry or just being careful not to move it after making a preliminary cut.
I first used a Stanley BackSaw Miter Box when first learning to do these and with that saw it was necessary to do a coped inside miter because of how difficult it was to get a consistent cut. With today’s powered miter saws I don’t think it is necessary to do a coped inside corner as long as you cut to what the angle truly is or a little under it’s true angle.
One little visionary point about looking at the saw and the material to determine which end to cut. With the molding top upside down to lay on the base of the saw a left hand cut on the ceiling will be a right hand cut in the saw. That is it will be upside down and held by the left hand and cut by the right hand if it was on the left looking at the ceiling where it is to be placed. From there it is just a matter of long on the base for the outside and short for the inside. That’s what I call the “long and short of it”.
b Acquiring the angle
There are tools for acquiring an angle such as a framing protractor or some others that have been mentioned on this group. There are even ones that can get an inside or outside corner angle measure and look to be really accurate but aren’t and are expensive. However I have found nothing better than just a plain old Speed Square. It really is quite easy and accurate to use to make a quick determination of what the inside or outside angle is of a wall. If you’re not experienced enough and feel uncomfortable with your first impression of what you think the cutting angle should be it is always possible to cut a scrap piece of wood to check it out first.
By putting a speed square into a corner you can see if it gaps to the back or to the front. If you see about a 1/8th-inch gap with a 7-inch speed square the angle is either 91 or 89 degrees. The cut is really on the inverse of what you would read. That is, the 91-degree inside corner reading would be considered as 89 and the miter set to 44.5 degrees. An outside miter reading of 91 degrees means the miters setting needs to be 45.5 degrees.
Visualize the Speed Square as being 1/4 of a clock. Continuing in its arch it will be going to the next second or in this case degree of arch. If the gap is so great that it is next to impossible to determine whether the angle is 4,5 or more degrees a scribing tool or measuring tape can be used to measure the distance of the gap. Then the marked blade of the Speed Square can be checked by using the scribe to see what the approximate angle is. This can be done while at the wall by just opening the scribe to the size of the gap then closing the gap to read the angle of the spread scribing tool. It can also be looked at in another way. Consider where a tapered sliver of paper would lay if you cut it to fill the space. This may seem like trigonometry and it is but this takes out the mathematics. The Speed Square is nothing more than one quarter of a circle with a straight line to make a triangle of the 1/4 round of a circle. Just keep that in mind when using it. See the circle continue and then fill it.
If you have an inside corner which is say 30, 45, or 60 degrees the Speed Square can be used to acquire an angle there too. You can use either another square or a squarely cut piece of board to set into the corner’s one side and then have the blade over lap to read the degree of over lap. This can fool you because the blade is 90 degrees at the point of reading and if your corner reads as 60 degrees with the use of a block that isn’t true. It’s really going to show the inverse of what the wall is. In this case the wall’s corner is 30 degrees and the cuts need to be 15 degrees for each piece. A 45-degree corner that reads 44 on the Speed Square when using a block is really 46. If you are going to be cutting corners like these you well find cutting both pieces to the needed angle is the only way to do it. Coping is next to impossible in this case so you just as well learn to double cut all corners. Coping is handy to have available for special circumstances.
For outside corners use a piece of wood which will lap past the edge of the corner on one side for at least the length of the Speed Square. Then put the Speed Square next to it and note the gap either being at the front or rear of the blade. If it is at the front the angle is greater than 90 and if at the back it is less than 90. If the cuts need to be greater than 45 degrees its handy to have a miter saw capable of going past 45 degrees. Otherwise you’ll need to know some other tricks to making a larger angled cut on a saw with limited angle markings.
Now this is where a little extra explanation can help. If you use material that can conform to the wall and the crown is small enough to do the same there may be a bit of a dip into which the material will be laying because of the mudding of the outside corner with corner beading. This will increase the angle at an outside corner if the dip is great enough. If the crown molding is stiff then use it or something else that matches its stiffness. If it’s flexible use it or something else that will match its flex. When crown molding is flexed it will change the angle of the lay. That is, if you push it into the dip, depending upon how far it is back from the corner and how deep it is, you’ll see the crown molding will tip out at the top. To close this is not too hard but it makes for a forced fit at the outside corner if it isn’t considered and compensated when cutting. It is possible to adjust the material in the bed of the saw to compensate for this problem and there by have an easy and perfect fit. Just take note of the difference of how much closer to the ceiling the bottom edge has to be adjusted when the material is pushed into the dip. It usually isn’t really much at all just maybe 1/16 of an inch in most cases but that can be enough to make a difference. Now note in the fence how much closer to the bed you need to be and make the cut. It is also possible to compensate for this when doing flat lay cuts on a radial arm or sliding saw but it has to be done using the formula for that, not an easy task for many but just too cool when you succeed. http://www.wwforum.com/faqs_articles/miter_formula.html#top
b Marking and installing the Material
All marking of the material is done on the bottom or wall edge. Because some of the jobs we have are on tall ceilings it is often necessary for us to cut our pieces from just a measurement. This measurement may be inside corner to inside corner or outside corner to an inside corner. I always cut the inside corner first and then the outside corner. It’s much easier to pull the tape to the next cut than hold to a “guess it’s there”.
If it is possible for me to do so I prefer doing outside cornered wall runs first and then the inside to inside corner cuts. That way all the outside corners are done and the inside cuts can be snapped into place and the corners fitted. I also don’t nail within the 3 to 6 feet of a corner, if I can help it. This way it allows me to make adjustments to the material to usually shove it up to make the top come together at inside corners or allow movement to the outside miter cut to make the fit just so.
I have tried to make this as visual as possible but usually only someone with some form of extended carpentry experience is really going to be able to install crown molding. It is a challenge to do but really satisfying when it’s done and done well. I just hope this little bit of information helps you to be able to do it yourself.
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Not sure I understand how the Delta crown chart works. Bevel and miter angles are given. Does this mean that in order to use the chart the molding is laid flat (or vertical) in the miter box?
*Flat -- more convenient sometimes, and some people do it this way all the time. If cutting the crown propped up, you don't really use the bevel.
*Any specific suggestions for "backer blocking". I am in the framing stage of a house and was just about to get to that. On the ceiling and walls? Walls only. Corners only? I would expect, for starters, where the ceiling joists are parallel to the walls, the drywall backup should be as wide as possible.The house is to have 3 pc crown consisting of 4 5/8" crown, base on the ceiling and inverted base on the wall. One room has 4 pc crown that includes dentil. It is to have other interior cornice mold as well. TIA
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we're remodeling a 1910 bungalow and so far it's gone pretty well. But now we're trying to cut and hang the crown moulding. For a couple of people who had a difficult time passing college algebra, it's been an nightmare trying to determine and cut the proper angles for the corners. Is there a simple formula to help in this process?