What matters when you’re laying out a coffered ceiling is the size of the finished beam, not the size of the crown molding. And you have to use the Outside Dimension of the full finished beam—the O.D.—not the backing or substrate you might be installing first.
I make my coffered ceilings using what I call “hollow backing.” I make three types of hollow backing shapes or forms: one is for beam intersections and is shaped like the intersection of two streets (see TOP form in the photo to the right).
I make another simpler shape for locations where beams terminate into walls. I use the same form for mid-span backing—when I want to support a beam between intersections, or when I’m running a single long beam across a ceiling. I usually install mid-span hollow backing about every 2 ft. (see LEFT form in the photo to the right).
For ceilings with perimeter beams—half-beams or full beams right against the walls—I use L-shaped hollow backing for intersections (see RIGHT form in the photo to the right).
But don’t be confused by the backing. The real O.D. of the beam is the face of the beam itself, not the backing. When you layout a ceiling, you have to consider the finished O.D. of the beam, from the face of the beam to the face of the beam, then (as Jed Dixon always says), you have to work back to the rough or the backing.
Construction Master Pro
If you’re using a Construction Master Pro calculator, you have to do a little imaginary math. Here’s why: There’s an unequal amount of spaces and beams. In order to make the math easy, you want to work with an even number of beams and spaces—and there’s always one more space than there are beams; unless, of course, you’re installing half-beams around the perimeter of the room (more on that later).
To make the math easier, add an imaginary beam. You can’t add an imaginary space, because you won’t know the dimensions of the spaces until after you’ve calculated the layout. But you do know the exact O.D. of the beams. This technique is very similar to laying out wainscoting: with wainscoting you subtract the last stile; but with coffered ceilings, you add an imaginary last beam.
Let’s use a simple and small ceiling as an example, something we can fit into a tight drawing—an 8 ft. x 10 ft. room. We’ll install three beams across the 8-ft. span. The O.D. of the beams is 5 in. To make the math easier, I’ll add an imaginary beam outside the ceiling, making the calculated span 101 in.
Now the job is easy. Simply divide the calculated span by the number of beams or spaces: 101 / 4 = 25 1/4 in. Remember, that’s NOT the space between the beams! That’s the size of the space PLUS the O.D. of the beam.
To layout the beam locations on the ceiling, measure across the ceiling from one wall, and strike a line at 25 1/4 in. That mark represents the back face of beam #1.
Now use the calculator’s memory to locate the succeeding beams. Press the + (“plus”) button followed by the = button. That sum—50 1/2 in.—is the back face of beam #2.
Don’t press the + button again. Just press the = button to find all other beams. In this case, there’s just one more beam—at 75 3/4 in.; but if there were five more, you’d press the = button to locate the back face of each one.
The CM Pro smartphone application also has a “Tape” feature, so if you forget one of the layout numbers, or when it’s time to pull a tape from the other end of the wall, just hit Convert and then the = button. The CM Pro “Tape” records every keystroke you make, so scroll down through the first few calculations until you get to the series of “Sub-Total=” lines.
Once all the beams have been laid out to their finished dimensions, work back to the rough substrate or backing. I normally snap lines just for the backing, not for the finished O.D. of each beam.
BuildCalc has an advanced “Baluster Layout” feature, and it makes laying out everything extremely fast and easy—from balusters, to wainscoting, to coffered ceilings. If you’re using BuildCalc, check out all the advanced features, especially for laying out stairs.
To use BuildCalc’s “Baluster” feature for coffered ceilings, start by pressing the CONV button, then press the Baluster button (when you press CONV, the “Stair” button changes to the “Balstr” button).
The advanced features in BuildCalc are a little like setting up a story pole—the calculator will do all the mental work for you. Here’s how to set up the “Baluster Function” for a coffered ceiling:
One of these days, BuildCalc will probably be able to calculate coffered ceiling layouts for half-beam perimeters, but right now it can’t, so if you’re not installing full-size beams around the perimeter of the room (that rarely looks good, especially in BOTH directions!!), leave the “Members at ends?” option blank.
Most carpenters like to measure from a wall to the face of a beam, rather than to the back face of a beam. If that’s your way, then be sure to choose Layout Marks at: leading edge—that way you can strike measurement marks at the finished face of each beam, then work forward 3/4 in. and snap lines at the rough substrate or backing. I like to snap lines on both sides of the hollow backing—that way, I never make the dumb mistake of installing the backing on the wrong side of the line.
The last step is to enter the number of beams—and don’t add an imaginary one! In this case, under “Number of Members”, enter 3.
Scroll down the screen and you’ll find the layout measurements: Member 1 is at 20 1/4 in.; Member 2 is at 45 1/2 in.; and Member 3 is at 70 3/4 in.
Oh, wait! I forgot to explain how to lay out ceilings with perimeter half-beams! When I do rooms like that, I just measure in from the wall and mark the finished O.D. of the perimeter beams. I subtract that sum from the overall span of the ceiling, and then use the result as the actual coffered ceiling span—as if the room is made smaller by the perimeter half-beams. Yeah…I bet there’s a much easier way…
Awesome, Thanks Gary! Timely info as we will be laying out black walnut beams very soon. Nice plug for both apps too.
On a ceiling with perimeter half-beams, why couldn’t the two half-beams stand in for your “imaginary beam” and allow you to evenly divide the space of the entire room? You would still have to measure out half the width of the beam to start your layout but it might make the initial calculation simpler.
Half-beams aren’t the same dimension as the full beams, so they can’t ‘stand in’ for the imaginary beam; and yes, you have to measure in half the width of the beam to start your layout. Or am I not understanding your suggestion? That wouldn’t be a surprise.
I’m referring to both half-beams taken together and treated as one full beam for the purpose of calculating the spacing.
1/2 beam + full beam + full beam + full beam + 1/2 beam = 4 beams and 4 spaces
Room dimension / 4 = spacing + beam width
Start the layout 1/2 beam width from the wall, measure to trailing edge, and you should come out 1/2 beam width from the other wall.
This seems easier to me but maybe it’s not.
Used Gary’s mounting system on painted kitchen and stained library ceilings in the same house, made install easy ! The issue was layout, there were existing recessed lights, HVAC ceiling registers and existing cabinets with various projections. The library was pretty straight forward , the kitchen took a lot of time to get a pattern that “looked right”
I wish there was more pictures for the article…… That’s the real candy of an article : ) Gary why don’t you make a carpenters book of all books. Your techniques are both professional and user friendly. Always look forward to seeing the articles you post. You are like a ” father” to many in the trade. Blessings!
So… Basically this is an article about the Construction Master Pro Calculator… I let SketchUp do all my calculations, all I needed was room size and beam width.
A couple things to consider, first, you don’t need to use a “hollow backing”, it’s a waste of material and raises costs and weight significantly. Simple cleats about 2″ wide is plenty of support for the false beams.
Second, remember to factor in the additional weight you will be adding to the room, if you are doing a large room, instead of using 3/4″ MDF, consider Ultralite or even foam. I did a room that was 32×18 with no support except for the joists and had to get an engineering survey done before hand.
The article is about using construction calculators for layout…I also explained how to use BuildCalc on a smartphone, not just a Construction Master.
Yes, Sketchup is great. But I don’t know many people who carry a laptop to the jobsite and draw every ceiling before they start work in the morning. In fact, I didn’t know anyone that does that until now. Most of the crews I know want to get right to work. And, just as you said, they need to take into consideration a lot of as-builts, too. A construction calculator allows you to do that, without drawings.
And no, I don’t think simple cleats on the ceiling provide backing for the bottom of the beam. And it’s the bottom of the beam that needs to be placed so that the sides can be added.
But all is not lost! I really liked your photos! You should write an article for TiC on installing coffered ceilings!!
I too use sketchup for designing, and make a RCP with dimentions and print them out. I think the best use for sketch up is getting the design and transitions worked out especially with intense ceilings such as the one in the picture you posted. Sketchup could of really helped to solve the major issue I see in your picture of that column not centered and lined up with the beam overhead, as well as no capital to support the beam. The design and layout are both so critical, they don’t work without each other.
I think knowing both and using a calculator is so critical.
I find that for a simple layout like this I prefer to just add the combined total width of the beams, in this example 15 inches, subtract it from the total width 96 inches and divide by four which automatically gives the 20 1/4 inch spaces between beams. I guess it’s just another way of going about the same job.
Yep, that’s the way I used to do it before I started using a calculator and getting precise layout measurements all the way accross the ceiling, so I don’t have to keep moving my tape and holding it on a measurement mark and measuring space to space, laying out the width of the beam, then measuring space to space again. That’s also the reason I don’t measure from center to center.
I just wanted to add that not only is the ‘stepping off’ method more time consuming and prone to error, it is also subject to cumulative error!
The example used in this article was a nice round numbers for simplicity, 96 in. However, if the ceiling dimension was 96-5/8 in., it would make things a little more difficult to simply step off the spacing that way.
96-5/8” (96.625) – 15” (5” beam width x 3) = 81-5/8” (81.625)
81-5/8” (81.625) / 4 = 20-13/32” (20.406)
Most finish carpenters would round that 32’nd up (or down) to a 1/16 in.–making it 20-7/16 in. or 20-3/8 in. Regardless of how it is rounded, it will still be off by a 1/32 in. That might seem insignificant, but after three spaces, that 1/32 in. difference grows to become almost 1/8 in. After six spaces it’s almost ¼ in… after twelve spaces it’s 3/8 in… and so on. Even 1/64 in. (or less) will add up over a large distance!
Calculating running measurements with a construction calculator for ceiling beams, fence pickets, wainscoting stiles, or balusters, will always speed production time and benefit quality.
What Todd said…and more:
We try to make all of the coffers the same size, especially if the coffers are small and there are lot of them, and I mean exactly, so you can cut all the pieces the same length and pre-assemble all the ‘field’ coffers quickly. The perimeter coffers on two walls usually end up with slightly different measurements, but at least the majority are the same size. That also speeds up production and improves quality. That’s what calculators are good for. And they’re a cheap way of achieving that result quickly.
I don’t know why every time I see an article about using a calculator, there are carpenters who reject the idea. I remember one carpenter told me he didn’t allow calculators on his jobs–he wanted his carpenters to learn how to do the math, to divide fractions, to work with cumulative error. I guess I have a different attitude. I want to get the job done quickly and accurately and as easily as possible. Trust me. Try a calculator. You’ll like it.
I agree with all of this. Ive had a construction master for many years and use it often. I do however think there is some merit to learning more than one way to do every task even if one is predominately used over the other. That includes learning how to lay things out without a calculator. I feel any new carpenter who only learns to use a calculator is short changing him/her self. It makes me think of the first contractor I worked for, I wasn’t allowed to use any kind of nail gun for 6-8 months, he wanted me to know that basic of skills- how to accurately swing a hammer. I realize there are differences in that analogy to using a calculator. It’s just that little something to me to teach someone how to know how to do it without one even if they don’t use it too often. I enjoy all the articles on TIC Gary keep it up!
Gary, I like your system for supporting coffered ceiling beams, and I like the efficient way you use the Construction Master or the BuildCalc to lay them out. I’d like to see this article about five times longer so I can learn all your tricks!
To layout equal spacing problems I just use the plus, minus, divide, equal and memory buttons on my foot-inch calculator. When I start with a half beam, or half newel in stairs, I just start with that number then add the equal spacing number which I’ve stored in memory. I don’t use the stair or baluster spacing functions- maybe because I’ve never figured them out (I didn’t read the manual), or because I like to do things my own way.
Or else, if I have time, I take good field measurements and bring them back to my office and draw everything on AutoCad. Then plot out a good drawing with lots of dimensions to bring back to the job.
No matter how you do it, everyone is right about this: You’ve got to design it before you build it. And, when you lay it out, you’ve got to start with the finish,and work back to the rough!
Of course I start with the finish and work back to the rough–I’m not a dummy student. When I learn something from a carpentry like Jed Dixon, I remember the lesson.
Gary, you’re always full of insight and positive attitude. I’ve haven’t done the hollow blocking before, just built the backing in place. Looks like would save time & material. Wish I had know that trick before the last ceiling I did. As for layout, calculators are indespensible.
Good article on the basics of symmetrical layout. I use the same basic process for railing posts too. When is the next step article coming?
I’d like to know your thoughts on how to approach coffered ceilings in rooms that aren’t rectangle or have obstacles such as cabinetry that hits the ceiling on 70% of a wall or cabinets a foot shooter than the ceiling (just pretend they aren’t there?) and also say a 45degree window bump out in the center of a wall span. Those types of issues are the ones that have me drawing out 5 different ways to do it and second guessing my decisions.
Oh and not using a calculator is foolish.
GREAT idea for another “Layout” article!! You hit every one of the hot issues! When can you get that article to me? We’ll do the illustrations, but a few photos might help! :)
I’d love to write an article if I knew the answers. I’m not sure I do though. That’s why I asked!
You mean a PITA one like this. : ) ?[img]http://www.thisiscarpentry.com/wp-content/uploads/2012/08/rsz_100_2473-1.jpg[/img]
Is there a reason you can just use like pieces (not full length) of 2 by 6 or whatever width and screw to the ceiling for supports….then preassemble the u-shaped beams first and then fit over your 2 by 6 and screw in? then the screws would be covered by crown molding?
Is there a reason this wouldn’t work so you wouldn’t have to make those “hollow backings”?
That’s one approach. But it’s much easier to fit single boards at the intersections and at the wall terminations, rather than having to scribe three-sided beams.
I’ve just finished the kitchen design and have been told the GC and my clients want to put a coffered ceiling in the kitchen/dining room/great room that will be created when the existing walls are removed. I thought of the challenge to design the spacing ( the contractor may have a plan and we meet on Tuesday) and wanted to get some insight as to the way it is done and how it would look. So…I found your website and just saw the coffered ceiling and juncture with the cabinets in the above photo. having seen it, I would prefer to have a fascia above the cabinets whose depth varies from 12″ to 25″ so that the beams lay flat against the fascia and do not intersect the cabinetry below. Are there more photos or information showing that concept? Thank you.
I’m not sure what you mean by fascia above the cabinets. Are you talking about a soffit? I can’t imagine anything else that would vary from 12″ to 25″. Personally, I think more about the crown molding: it should be applied to the cabinets, too–same crown that’s in the coffered ceiling. So if the crown is in the kitchen, the beams should be, too.
This seems to be a great method for installing coffered ceilings, one thing you didnt mention is how you fasten your hollow backing units to the ceiling. If you dont get lucky enough to land under a ceiling joist, how to you ensure they are secure? especially in the case where heavy hardwood facade is installed over them.
I use PL Premium adhesive to secure the hollow backing to the ceiling, along with 15 ga. 2 1/2″ nails. If there’s no joists in the area, I cross nail to hold the backing up until the glue dries. Remember, as soon as you start installing the crown, the whole diaphragm is solidly secured to the joists and the ceiling, though the glue by itself will certainly hold. I know this from experience–try removing one of those pieces of backing and you’ll be pulling the drywall off the ceiling in pieces.
Thanks for the quick reply on my last question. The other thing I was wondering about was how you approach hanging your crown. Many people seem to prefer cutting and gluing up the crown on the bench then hanging as a single piece. If this is your preferred method, I would imagine you also miter your corners instead of coping, correct? If you put them up in single lengths I would imagine you cope as you would with a typical crown installation.
Thanks for your insight (and a great article by the way)
I use both methods and for specific reasons. I like to pre-assemble crown when the pieces aren’t too big and I can complete a lot of inside or inside and outside corners quickly and perfectly. But I also like to cope inside corners and move to my right around a room. If the pieces are long or difficult to install, I cope; if they’re short and can be handled easily, I pre-assemble. I’m in the middle of installing a coffered ceiling in my living room/kitchen. I’ve pre-assembled six of the big coffers–both the crown and the bedmold that the crown fits inside. But all of the end coffers that abut walls are being coped, even though they’re much smaller. That’s because the coffers are irregular or because it would be tough to get the pre-assembled frames into some of those tight areas. It’s always good to have several different methods for doing things.
Thanks for the info on layout. Very helpful. I have a popcorn master bedroom ceiling that I want to get rid of and thought coffering would help me do that. I figured I would add a drywall piece before the inside molding. Saving me from re-boarding the whole ceiling. Any advice on materials if the ceiling will be painted all white?
Hello again Gary,
Do you have any thoughts on using MDF stock to build the ceiling vs solid wood? Normally I would never consider subbing MDF for solid wood in trim applications but since its a ceiling, it will never get touched and the thought of all that wood contracting and opening up paint gaps gives me anxiety.
I don’t like the idea of using MDF because when you install the beam bottom, you’re nailing into the endgrain of the MDF, which has no holding strength and will split easily. In this case, wood is good. Use dry material. In most parts of the country, you can find a source for fingerjoint jamb material in 16′ lengths. It’s reasonably priced and dry.
Pre-assembling the coffers seems to be easy enough and the quickest way to complete the ceiling. But can’t it be somewhat difficult to raise the assemblies into the hollow backing components? I am working on a ceiling that will have 42 inch square assemblies. I realize what you mean by exact, but some clearance is needed to make inserting that assembly a little easier and if so what would you suggest?
We subtracted about 1/32″ from the I.D. of the hollow backing for each bed molding measurement. And we subtracted nothing for the crown. The crown slips in easy at the top becuase it’s angled in. If the bottom of the crown hangs up a little on the ends of the bed molding, and you can’t slip it past, plane off a little from the back of the crown–just a little, and it will slip into place. With the size coffers you’re using, you’ll be able to bow your pre-assembled pieces, too, as least in one direction, which helps a lot, too. I hate subtracting too much for ‘wiggle’ room becuase then the joints would be tight at the intersections!
Just one more question. I envisioned the pre assembly being the crown and the 42 inch square side boards that they are adjacent to, to be one unit. But your reply seems to indicate they are two separate assemblies. I think I would prefer them to be separate, but assembling the crown would involve more work. I think I may not be fully understanding the process. Hope you can help me out.
Here is a link to a JLC article that explains the process.
Love all your techniques and tips. Have a question about a project. I have a 15’x15′ Living room with 10′ high ceilings. What dimension should I make the beams?
It’s usually the height of the room that matters most, though the dimensions are critical for small rooms, too. I’d say your room is on the edge, not big, not small, so I’d consider 3 1/2″ to 5 1/2″ wide beams, and not make them much deeper than 5″. But that’s totally my opinion. Others might have a different opinion.
For a room this size would you suggest a 9 or 12 square grid? I like the idea of 12 and having a beam down the center of the room, however, I’m not sure if 12 squares will be too much and too busy looking. Thanks in advance for your input.
Heres a ceiling i layed out.
I used 2×6’s lag bolted to the ceiling joists as supports and added another layer across the bolted sections, everything else is poplar 1x.
I had a question about some of the other pictures of coffered ceilings on this thread.
Why are the main rails lower than the cross rails? Every one I’ve ever seen or done from scratch–all the rails are even on the bottom.
Am i doing it wrong or is this just an aesthetic choice or were those kit ceilings?
There are a wide wide variety of coffered ceiling styles, many of which are specific to individual historic styles, period styles. And there are also a lot of different ways to install them. These days, with all the adhesives we have, whenever I see someone using lag bolts, I’m surprised, and using solid lumber for backing also makes the job tougher. Solid lumber backing is never straight, or even close to it, and it’s never dimensionally precise either, which makes it tough to establish layout and backing that’s precise enough to pre-assemble the coffers. But everyone has their own approach, so whatever works for you!
Hello everyone, I have a customer wanting coffered ceilings in her living room and kitchen. They are both
one great big room. 15’x40′ total. The living area being 14’x20′ and the kitchen being 15’x20′ my only transition is along the interior lenght wall where a small 1′ return jots in that 12″ to go from 14′ to 15′ in width where the two rooms seperate at tile to wood flooring transition. This room is square except the one return. My Dilemma is finding the accurate beam size for the coffered ceiling so that both rooms look uniform together and the layout is accurate. Someone please help.
Amateur carpenter here. I LOVE this site! Have a question for Gary or anyone else who can help me out. I am building a coffered ceiling in my theater room. I’ve built my hollow boxes and am in the process of mounting them on the ceiling. My guide lines are snapped and the boxes dry fit really well. My question is, should I use shims to make sure the boxes are level before securing them in place?