Coffered Ceiling Beam Materials
The design is calling for 3/4" solid material on the two sides and bottom of the "beam". The sides will be attached to cleats secured to the ceiling. The design is roughly 15' x 15', so ideally I'd like to use 16' lengths to minimize joints. I've considered 1x poplar, 3/4" primed MDF, 5/8" MDF or 1/2" birch ply for the box beam. Anyone have a suggestion?
From contributor L:
You’re asking about the beam itself, and not the mounting material "underneath" the beam holding it to the ceiling, right? If it's getting painted, and unless there is a good or required reason to use real wood (like it will be "distressed" before or after installation), MDF is the way to go. It's dimensionally stable, holds a good detailed edge and paints out well. You might get someone to fingerjoint two 8' rips into your 16' pieces, but a scarf joint made on site would work well since most coffered ceilings are high up and finished dark. If it needs be real wood, use poplar. For the mounting blocking, I’ve found rips of 1" (or 1.125" subfloor material) plywood to work well. If you need more thickness, double it up. 2x6" dimensional lumber could twist on you and make it a struggle to get the beam installed.
From contributor V:
How big are the beams? You can get primed MDF up to 1x12 in 16' lengths, so that's an easy method (if heavy). I'm thinking plywood would be most difficult because you'd need to have some joints. Depending on your layout, that might not be a problem though. Last, but not least, poplar would be a great way to go - it's just the more expensive option (Poplar ply = $1 +/- per square foot, MDF about $.60, Poplar around $2.2).
From contributor G:
If you look at the picture as a whole then poplar will probably be cheaper. The extra labor that you are going to introduce to make each one of the seams seem like they aren't there will probably offset the cost of the solid stock rather quickly. You only have to lift one pc and you won't have to have to deal with the seam at all. Going from MDF to poplar will cost you about $9 each. In my world that is about 9 minutes worth of time. If it will save you that much time you'll break even and it'll make the job easier. If it saves you more then you will profit by doing it this way. Figure out your own pricing, I just did it off the top of my head and didn't calculate it out.
From the original questioner:
Thanks to all who offered assistance. We'll be going with the 1x poplar for the box beam. I was leaning toward MDF but was hesitant due to the weight. We'll be preassembling the "beam" on the floor and then lifting it into place. Just felt that the poplar would be more rigid than the MDF and not flop around as much. All the other mouldings will be MDF. Once again, thanks everyone for your opinions.
From contributor M:
In the future if you want to use MDF try the "ultralite" – it’s less than half the weight of regular.
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