Best clear exterior finish for oak door facing south?

['89cab]

I just purchased a new front door which is not installed yet. I did not have a clear varnish applied because I was concerned about exposure to sun and moisture (rarely direct rain, but fog and normal coastal moisture) particularly to the bottom third of the door. Because of its size, weight, and cost I don’t want to take it off and refinish any time in the future.

I’m thinking of applying exterior tung oil to the outside and satin Varathane to the inside. I’m assuming I will reapply the tung oil every year or so.

How about tung oil on inside as well? Is marine varnish appropriate?

Recommendations?

[Zeke]

I don't think an oil only finish on the outside is what you want. If it is, you will be applying it a lot more than once every two years. Think every 2 months. Also, be careful when applying any clear over an oil stain or penetrating oil. You may get some reaction and some reactions aren't pretty.

Marine products are appropriate but sometimes not user friendly. If I were using a marine varnish, I would want a clean room and the door flat on sawhorses. It likes to run. The rest of the products available now in CA aren't worth the time or effort. The VOC laws have ruined the formulas. I'll bet we use half again much more paint these days due to premature failure. Makes a lot of sense, doesn't it?

A quart will do 8 door sides, one coat. Have someone ship you a quart of the good stuff from AZ or wherever. I'll bet the formulas in FL are pretty good, but I don't know.

[Porsche-O-Phile]

Good question.

With a south-facing door (in the northern hemisphere, I'm assuming) you'll have more solar exposure and therefore I'd consider UV resistance to be an important feature. Other than that, not much to add to what's been said.

[Rusty Heap]

YUP, I've used a marine spar varathane with great results on our south faces outside deck door.

[dipso]

A god oil-base marine varnish will work. Like Milt said, see f you can get it out of state. I have a south facing wood door with McCloskeys on it, seems fine.
The oil based enamels were discontinued about 6 to 9 months ago. You can still get oil primer and lacquer though, so oil varnish might still be available. I don't know.
Make sure you varnish the top and bottom of the door,inside the knob holes, as well as behind the hinges. This is very important if you want to keep the door from swelling and/or soaking any moisture.

[John_AZ]

My home has a N/S exposure. Entry doors on north side have MinWax Helmsman and hold up well. The Helmsman did not hold up on the south side doors after 1 or 2 seasons-depending on heat and monsoon.



I am not familiar with CA and VOC approved levels.

My south doors are exposed to the harshest climate in AZ and require work every year. I replaced 4 french doors with steel and leaded glass inserts-basicly 3 pane thermal. I got tired of the work.

This Old House has this solution for southern exposure doors:


Q: I have completely refinished my solid-cedar front door twice—by sanding it to bare wood, staining it, then applying a marine spar varnish—but the finish still doesn't hold up long under our fierce desert sun. Is there anything I can do to help this door?

—Mary Zahora, Gold Canyon, Ariz.

A: Norm Abram replies: I can tell you from personal experience, with the oak threshold at my front door and the teak on my boat, that keeping a clear finish on outdoor wood isn't easy.

First, you need to prepare the surface properly by completely removing the finish and any sun-damaged wood. When the surface is pristine, apply at least five coats of marine spar varnish loaded with UV inhibitors; one or two coats isn't enough. Then, once a year, sand the varnish with 220-grit paper and apply two more coats, which provide fresh protection from the sun. That's what I do with my boat, and it's only exposed to the weather about seven months of the year!

If that sounds like too much work, and painting the door isn't an option, try an *exterior-grade penetrating oil like Penofin or Australian Timber Oil. Penetrating oils don't form a hard, glossy finish like varnish, so they can't peel. And while you'll need to reoil the door more frequently—at least twice a year—at least oil is easy to apply. I've used it on some outdoor furniture projects and it holds up pretty well if you keep after it.

Good luck,

John_AZ

[reed930]

I used Epifanes marine varnish on a '40s wooden diving board about three years ago. The board is exposed to prety harsh conditions, i.e. chlorine, UV, abrasion. It has held up beautifully. It's a bit more expensive than the big-box stuff but is worth it over the long run.

[charleskieffner]

well funny you mention this. had some doors to do recently. doug firs with marine spar varnish. all exposed to mega sun all day. marine spar varnish reacts with uv's and in 6-9 months starts to onion peel.

we went with 3 coats of acrylic clear coat. water based does not react with uv's. oil based DOES react w/uv's. as per our local dunn edwardo's.

[look 171]

I have 2 set of single lite french door in the back of the house that face west. The are one year old Fir doors. on one set, it has 3 coats of marine poly. The other, I coated it with a 2 part epoxy. I think it will out last the poly, we will see. The oil base poly doors have patina nicely. I think the tung oil will only work on oily woods like ipe and teak. I have a Ipe deck treated with Penofin. That my friend, is good oil. I usually oil once a year. UV protection is great. The Ipe isn't gray yet after 5 years.