Interior and Exterior Wood Door Construction Specs
Door makers discuss what is adequate thickness for large interior or exterior doors, and whether to laminate or use solid wood for stiles, rails, and panels. October 2, 2007
Question
I've got a two part question. First, are interior doors (A. mahogany) 1 3/8 x 36 x 93" with a lock rail and a raised panel top and bottom? Can I get away with stile and rail milled out of 8/4 material, or would you do a sandwiched glue up with epoxy? Second, exterior doors same material but 1 3/4 x 42-48 x 93"... I will definitely sandwich S&R, but would you use two 5/4 boards and match for color or would you resaw 9 or 10/4 and then glue back together? I've got a lot of doors, so I would like to use the easiest way possible but still make sure they are engineered properly, and yes, these will all be flat jointed, etc. I live in Hawaii so we don't have extreme weather fluctuations.
Forum Responses
(Architectural Woodworking Forum)
From contributor D:
My initial reaction to the interior door specs is that it is too thin at 1-3/8... For a 36 x 93, I feel that they should be at least 1-3/4" thick, and 2" would calm my fears of stress warping/flexing. For interior use, epoxy is overkill, unless you feel you will need a long open time.
For the exterior, going the laminated route is great insurance, but again, at 1-3/4", I feel it's too thin for the dimensions you quote... I'd personally not do it less than 2-1/4" thick. Much more stable, much better sleep! For glue, again, epoxy is okay, but polyurethane would be better for tight joints/miniscule glue lines - if you do use epoxy, don't clamp it too hard, or you risk starving the joints.
From contributor G:
I would make the interior doors 1.75 in thickness with 3 laminations for the stiles and rails, 2 laminations for the panel if it is to be at least 1.375 inches thick using TB2 or similar glue.
Exterior 2.25 with 3 laminations for the stiles and rails and 3 laminations for the panel regardless of the thickness using TB3 or TB2 or epoxy depending on exposure. Grain and color for me depends on the finish and client's wishes.
From contributor M:
You people don't build any doors for profit, do you? How do you make any money laminating 3 layers of wood for a 1 3/8" door? Get on with it and quit worrying.
From contributor D:
I get paid very well for my laminated exterior doors specifically *because* they're laminated solids. Regardless of method, would you build a 36 x 93 mahogany interior door at only 1-3/8 thick? Aside from looking disproportionate, it would be a tad floppy. I agree that laminated for interior is over-engineered, but if the customer wants genuine solid through and through, laminating is good insurance. If they only want to pay for veneer, then no, laminated can not compare price-wise.
From contributor G:
We build doors with pride and for profit. We laminate all of our doors no matter where they go. We have clients, new and repeat, stopping by our shop everyday looking for work to be done. If they are shopping for price only, most of the time we don't do the job. We don't make 1.375 thick doors, period.
From the original questioner:
Thanks for the responses. I will change my interior door thickness, but I am stuck with the exterior width due to the sliding track. What is a ballpark figure that you would charge for an A. mahogany raised panel door that is pre-hung and laminated, say 36x93"?
From contributor M:
Cost plus profit is what I would charge.
From contributor A:
For a single door with just 2 panels it would be $2400.
From the original questioner:
Wow, $2400 - that seems pretty steep for 1 door! Good for you if you can get that price. On a separate note, do you stipulate in your contract about acceptable wood movement? For example, Walzcraft makes interior doors and their tolerance is (specified in the catalog) 1/4"(!) for 80" doors (and these are double lam). What's acceptable to you door guys?
From contributor G:
$450 to fabricate door and one piece rabbeted jamb. $90 to prehang, $180 to install on site. Lumber cost varies with type of wood. If we finish, $225 and up depending on what the owner wants. More or less, $1500.
