Exterior door-- solid mahogany or 3-piece layup?

[Roger Marty]

I'm interested in building an exterior door for a master bedroom (cold climate, rarely used door, protected by a storm door). Found some nice Freud instructions:

http://www.ptreeusa.com/PDF/EDMS-Instructions.pdf

What I have in mind is mostly a glass insert door with mahogany rails and stiles.

Should I use solid 8/4 Honduran Mahogany planed to 1.75" thickness or epoxy three thinner pieces to make 1.75"?

[Robert LaPlaca]

Roger, not to be Mr. buzz kill, but I just bought some 8/4 South American Mahogany, it was $11 bf (5 to 9" width). It isn't easy to find quality SA Mahogany and when you find it, it is expensive.

[Sam Layton]

Hi Roger,

When I built my front door I laminated the stiles and rails. I think it makes the door a lot more stable. I used titebond III for the lamination. In addition, instead of 1.75", I went with 2 1/4". I used three laminations.

Sam

[John A langley]

use African mahogany you could make a core laminate the edge and face, also one piece would work, not a very good picture

[David Kumm]

You you use true Honduran with fairly VG, it won't matter if laminated or solid. The dry Mahogany is so stable it will be more about the joint construction than the rails and stiles that will determine the life of the door. Not the case with the African or Phillipine substitutes. Dave

[Jim Becker]

I like the lamination method because it can actually help overcome the challenge of building a door with sturdy, deep "mortise and tenon" type construction since you can build in the mortises while laying it up, rather than having to cut them out from a solid piece of wood.

[John TenEyck]

At $11/bf I would use laminated construction for sure, plus it's more stable. I use Plastic Resin Glue to glue the skins on the LVL cores and for gluing up the loose tenon joints.

John

[Dennis Yamamoto]

John,

What LVL cores do you use? I've seen some folks make staves out of LVL's or LSL's and them glue them up into a stave core door. Is this overkill, and can I just laminate over a "solid" length of LVL?

Thanks,

Dennis


At $11/bf I would use laminated construction for sure, plus it's more stable. I use Plastic Resin Glue to glue the skins on the LVL cores and for gluing up the loose tenon joints.

John

[John TenEyck]

I use LVL beams, and use it as stave core construction. I sand the LVL to get any coating off, rip it an eighth over the thickness I need, turn the staves 90 degrees, and glue them together with TB 3. I rip the stiles out of that to the width needed, then glue on my solid edges. I joint and plane that assembly and then glue on the skins with PRG. Unless it's an arched door, I don't worry about the exposed core at the top and bottom, but you can glue in a block of solid wood prior to gluing on the skins if you want. For an interior door I use 1/8" veneer and 3/16" for an exterior door.

I can't remember which LVL brand I've used but can let you know if needed. I have one in my shop right now ready to make an exterior door. Fwiw, I let the LVL acclimate to my shop just like I do solid wood before working it.

John

[Dimitrios Fradelakis]

Is their a downside (other than price) to using solid Honduran mahogany? What if loose tenons or even the largest and deepest dominos were used in the construction of a exterior door?

[Jamie Buxton]

Is their a downside (other than price) to using solid Honduran mahogany? What if loose tenons or even the largest and deepest dominos were used in the construction of a exterior door?

A downside to solid Honduran Mahogany is that the quality of the lumber has declined over the years. It used to be that you could buy lumber cut from old-growth trees which grew in a deep forest. The lumber was clear with very straight grain, so it was stable, and the door didn't twist or cup. Nowadays the lumber just isn't as nice. That's one of the reasons that commercial door-building outfits use stave core construction. The idea is that the expansions and contractions in all the various pieces of wood in the core kinda balance each other out, and the resulting stile or rail is stable.

[John TenEyck]

Exactly. Composite construction takes a little longer, too, but the result is a very stable door that isn't going to go wonky as the weather changes.

John

[peter gagliardi]

With proper stock selection, a solid door will far outlast a glued up unit with a junk core. Any wood used in the core that is not as durable as the face wood, is going backwards. Every glue line between layers creates another impermeable layer that moisture will get into quicker than it can leave, leading to premature failure.
Don't kid yourself about what the big factories put out being the highest quality. They supply a product that is value engineered to #1. Make as much profit as possible, and #2. Provide the lowest cost to do so, while providing a very basic warranty. They use cheap cores, because they don't want to spend on a quality on, because they are competing on a cost basis first, vs a quality basis.

[John TenEyck]

The opposite argument is equally valid.

John

[Mike Hollingsworth]

358057
I made my front door from 8/4 Mahogany acquired locally at $11/ft. I got my panels from Irion in PA for about $50 ft. His stuff weighed twice as much. Coloration is nearly the same 6 months after I took the photo.

[Robert LaPlaca]

358057
I made my front door from 8/4 Mahogany acquired locally at $11/ft. I got my panels from Irion in PA for about $50 ft. His stuff weighed twice as much. Coloration is nearly the same 6 months after I took the photo.

Mike, ix-nay on Irion Lumber, it's hard enough to find quality SA Mahogany needed for period furniture, without everyone knowing where to source the quality stuff. Really good mahogany should be heavy, dark and finely grained..

[lowell holmes]

I personally would go with Mike's suggestion. My front door is vertical grain fir. I would never laminate an exterior door. But, that's just me.

[John TenEyck]

A pro friend of mine has built hundreds and hundreds of exterior doors over the past 25 years using laminated construction, and ships them all over the country. Not one has failed. That is proof enough to me that it is reliable.

John

[David Kumm]

I don't think the issue is whether stave core or laminated doors will fail- they won't- but rather if someone new to making doors, maybe new to resawing and veneering skins for the core, and glueing the solid edges, will gain enough benefit for the extra work. I don't know the experience of the OP but first doors are never as easy as the last. Quality dried and carefully chosen solid will hold up in a Northern climate protected and little used. Either method will likely outlast most of us. The sun has caused more door maintenance issues in my life than the number of laminations. Dave

[peter gagliardi]

No matter what method is picked, failure starts WHEN water gets in. And unless it is very well protected, water ALWAYS gets in. Just a question of time.
I have in the back room of my shop, a set of turn of the century doors that were stave core construction. I keep them because they are a nice design, I like to look at and study old methods, and because water got to them, and they failed. 1/4" veneer faces just peeling off, and staves behind separated at all the glue joints.
Came out of a very nice brownstone in Boston.
I replaced with solid, about 10 years ago.
Only about another 70 years to go to see which lasted longer.
Glue joints fail with moisture cycling, or the glue/wood interface zone. Less joints, and less moisture= less failure

Protect your door, whatever method you choose.

[Mel Fulks]

I've had to make doors to replace some older ones that were early stave core. Did seem they were failing from moisture. Was surprised they attempted that with old type glue. Haven't seen any failures with modern glues except on doors that did not have paint or varnish on top and bottom. We started putting large stickers on our doors saying all waranty claims would be void if top and bottom rail edges were not painted. I've seen no failures on doors made even with just "water resistant" glues that were well sealed on all surfaces. Have seen a bunch of mahogany doors get painted just several years out due to finish getting shabby.

[Bill Adamsen]

Depending on the stability of the wood chosen, I'd probably go solid, but if using a core, choose wisely.

I do a fair amount of work on wood boats. WWII introduced hot laminated (autoclaves) plywoods which were used extensively on boats generally smaller in size. Generally the approach was outside skins of the best quality materials (various mahogany ... best being Honduran) and then cores of either cheaper grades of Mahogany or sometimes secondary woods such as poplar. Laminations were glued and then stapled before being pushed into the autoclave to activate the glue with heat and applied pressure.

Fifty years later we get to see how those different laminations held up ... and let me tell you ... it's not always pretty! I have seen hulls that look perfect from the outside and yet the interior core of poplar is virtually gone. Obviously the hull is not a worthwhile restoration candidate. Hulls of Honduran Mahogany are sometimes as beautiful and stiff as the day they left the factory. What we refer to as Philippine Mahogany performs variably. Remarkably, the heat activated glues from fifty years ago hold up remarkably well. A door is not a boat, but the lesson is, choose the core wisely.

[rudy de haas]

My front door was made by Peter Gillighan many years ago (probably circa 1992?) and long before we bought the house. It is Honduras Mahogany over some kind of MDF core. It is well protected from the weather by a long overhang and the fact that it faces away from prevailing winds. Every few years I put a little oil on it and it looks brand new - we have low humidty, but temperatures range from below -40 C to above 34C.

One note about Honduras mahogany: it is quite soft. This makes it easy to work with, but bad for heavy use applications like a door in a busy business or office. I've been using Santos Mahogany for interior stuff (e.g. stair headers, bathroom cabinets): it's cheaper, harder, easier to get, and very similar in color.

[Warren Lake]

old guy made multi core doors that had to last 300 years. Another reason for stave besides stability is you can make any thickness you want. I wrinkled my nose when he said 300 years and he said go to Europe and look at Churches and Cathedrals. Some of the church doors were up to six inches thick with cores running in different layers he drew it once and I didint get it. He got belted once doing a door and making a short cut. He did city Hall here and the doors were designed by engineers with threaded rods and stuff. He told it wont last and he would not do it, he built them as they did in Europe and put a 25 year warranty on them. The owners of the company flipped out that he put any warranty on them.

I havent done big doors and do small ones as he did One thing comes to mind when you talk 1/4" outside veneer its going to fall on the profile somewhere. He said they tried to put the face into a certian place in the profile where it would not show much. Id think thicker would be better for a few reasons if you can get it out of the material you are starting with. 4/4 now isnt what it was in the past. pretty sure his usual outside thickness was 3/8". I had a church door cross section I cant find and last time he stopped by did a fast drawing of a 2 1/4 door, he saw a door here i took ouit of the garbadge of a company that closed and it just perked him up right away.