Entry Door Ideas for a Jacuzzi Building

Thoughts on building a durable exterior door able to withstand the steamy environment of a room housing a hot tub. December 14, 2009

I'm replacing a door in a Jacuzzi building. The room is about 20' x 20' with a twelve foot ceiling, and the Jacuzzi's more like a pool with its own waterfall - when turned on this room fills with steam. The original door has warped very badly. It's 36'' x 8' with a full arch on the top, 2 1/4'' thick Doug fir. It was a frame and panel door and it looks like they slipped in some (4) allthread bars horizontally to maybe keep this thing together or to keep it from expanding, which didn't work. It's about 36 1/2'' wide right now. The warp is vertically and inwards about a good 2 inches - time for a new door.

I'm looking at making it out of clear western red cedar. I haven't decided on the method for doing the rail on the upper arch - mortise and tenon some pieces together at an angle then cut the arch on the band saw, or rip some 1/8 inch strips and glue then with Titebond 3 or epoxy over a plywood template of the arch, then connect it to the stiles, then make up some 5/4'' x 6'' T&G V-groove and float in the panel area. In the old door they used metal decorative clavos for a medieval look. I thought maybe I'd drawbore the rail and leave the pins proud and hit them with a chisel or a hand plane. Any thoughts on this would be much appreciated. Also, the finish I'm really not sure about. How about half a dozen coats of boiled linseed oil applied over the course of 2 weeks? Pre-finish the v-groove before assembly, mix a little wipe-on poly in with it for the last few coats.

This is a ski resort type climate on the outside of this door and no, it's definitely not protected from the weather. I would of course prefer not to see my door warp the same way and not close properly or not at all, as the case is now.

Forum Responses
(Architectural Woodworking Forum)
From contributor L:
This sounds like a good place for a fiberglass door. But it would put you out of a job.

From the original questioner:
Thanks. I have looked at the fiberglass doors - quite nice and they will even stain them for you. The building is round with the walls being solid stone with a half dozen wooden windows, with wooden shutters, wooden lounge chairs, hand hewn wooden beams in the ceiling... I'd hate to be the one to spoil the architect's vision. For the 10 mil it cost to build a place like this it would have been nice to design an entryway into this building with an inner door to help protect the entry door.

From contributor L:

If they are willing to pay, I think teak would fit the bill. Otherwise white oak, mahogany, sapelle, Spanish cedar in that order. Use full mortise and tenon if you have the capacity, or very large dowels and water resistant glue. Epoxy might not be a good choice if there is a lot of heat, but it would be very water resistant. Coating the door with the epoxy as a finish would make it pretty waterproof also. West System has an epoxy designed for this purpose. I have never used it so I cannot tell you how it works. It is used in the boating industry frequently and is very durable.

From contributor B:
I'm not sure a stile and rail vg paneled door, no matter wood species or construction method, will hold up in this type of application. You have a lose/lose scenario. The exterior face of the door is exposed, cold in the morning, baking in the day, cold at night with what I assume to be a very low RH in the mountain environment. All the while the interior face of the door is going from a fairly standard RH to a very high humidity in a short period of time.

If you do decide to go through with it, what contributor L suggests would probably be your best option. I'll throw in ipe as another species suggestion. I would be hesitant to extend a warranty.

From contributor T:
Is it possible to apply planking to a fiberglass door - for purely aesthetic reasons? Maybe you come up with a way to mount it with the idea of replacing it later - something like a refrigerator door panel. I'd hate to ruin the architect's vision also, but that vision may be blurred if he/she can't see how it will hold up to an extreme environment. They should know better.

From contributor K:
Has anyone ever used poplar for an exterior door to be painted? If not poplar, what wood would you recommend to be painted as an exterior door? Clear pine perhaps?

From contributor S:
Poplar, as we get it today, is not of the slow growth variety with dense, stable heartwood. Although it does machine and paint well, it is subject to perhaps more movement than you might like for a door exposed to the elements. In addition, if the door stands a chance of getting wet as a fairly common occurrence, you will probably get some nice mushrooms growing. Not really the best choice considering all the labor involved. Look at more stable material and look at vertical grain if possible. We usually use mahogany, Spanish cedar, Doug fir and old growth dense redwood (reclaimed). Yes, even if they are painted!

From the original questioner:
Thanks, all. I'm going with what contributor T mentioned, nice fiberglass slab to begin with, stainless hinges and hardware, 1/2" cedar on both sides. Now, for fastening the cedar - Liquid Nails directly to the slab, or cedar mounted to 1/4" plywood slid in on rails like a sub-zero refer panel?

From contributor C:
Sounds like you have a pretty effective plan. Cross pinning all tenons will minimize critical movement in expansion and help things to expand and contract more evenly.

From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
Although cedar does not move as much as a wood like white oak, it still will swell quite a bit if it is 8% MC when you install the door and then the waterfall is turned on and the RH approaches 100% RH. You might consider putting on the cedar on the inside of the door after the room is operational and the RH is up and after the cedar has been in the room (uninstalled) for a week to gain MC. (Otherwise, maybe you can think of another way to increase the MC of the cedar before installation and then avoid having it dry out.)

From contributor N:
Epoxy is the stuff to coat it with, regardless of the species. It is standard practice in the boatbuilding world. Even better is to make a weak batch of clear epoxy diluted into acetone. Brush this on first, for extreme penetration and a plasticizing effect. Then coat normally. Be aware epoxy breaks down quickly under UV exposure, and would need to be further protected with a UV resistant topcoat like spar varnish.

From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
You can also buy epoxy that has UV stabilizers in it. But a topcoat with UV stabilizers is a good idea for sure.