Building laminated veneered doors

[Larry Edgerton]

Ok, while you doors guys are here I would like an opinion.

I want to build an exterior door for my own house with Padauk on the inside and white oak on the outside. I have built many commercial doors this way, Baltic birch or Appleply core with wood overlays on both sides, but always the same species. I did some tests with Padauk and White oak and the expansion rates are really close but still I hesitate. I lay up the layers with West System and finish with the same with 207, so moisture transfer is minimal, but still....

Thoughts?

[Malcolm Schweizer]

Malcolm, Are you dealing with Preservation Virginia or an architect who wants to make sure his client gets the tax credits? Sounds to me like the latter.

Thankfully, I deal with Preservation NC much more than Preservation Virginia, but what dealings I've had with Preservation Virginia were nothing more than pleasant and reasonable. I can't say the same when there was an architect between us.

Virginia Preservation, but I deal indirectly through the owner of the building. I think it may be dependent on who you talk to as to what they require you to do, but I have seen some pretty picky stuff. That said, they have also worked with the owner on some other things.

[Malcolm Schweizer]

Ok, while you doors guys are here I would like an opinion.

I want to build an exterior door for my own house with Padauk on the inside and white oak on the outside. I have built many commercial doors this way, Baltic birch or Appleply core with wood overlays on both sides, but always the same species. I did some tests with Padauk and White oak and the expansion rates are really close but still I hesitate. I lay up the layers with West System and finish with the same with 207, so moisture transfer is minimal, but still....

Thoughts?

These are my thoughts, and just to give advice, but you’ll get many answers and then you have to make your own decision- you know how that goes on forums!

Personally I am not a fan of plywood doors for exterior. I also build boats, and I know marine grade ply can withstand a lot, but aside from marine grade (true Lloyd’s certified) I don’t trust plywood for exterior. Now, let me be clear- it is done, and it seems to work- I’m just saying I prefer not to trust the glue up in the plywood itself. You are doing the right thing using West System for the laminations. I would not use it as an exterior coat. Even the 207 needs to still have a UV protector over it. Also, epoxy doesn’t flex and move with minute movements in the wood- not just from moisture, but from heat and cold. Epoxy will crack (I’m talking about epoxy used as a surface coat, not the glue up) and let in moisture over time. I have seen it many times in boats. I use a good marine varnish like Goldspar for exterior doors. Again, I’m talking about coating the exterior- you’re fine with epoxy as a glue for the laminations. It is what I would choose.

I see no issue with your wood choice for the veneer. It should be beautiful.

Edit to reiterate plywood doors are done for exterior- I just choose not to do it. It requires me to rely on someone else’s glue.

[John TenEyck]

I built an exterior door with white oak exterior veneer over an LVL core, with ash on the inside, with T-88 epoxy. One night a couple of months after I installed the door, when it was really cold, like zero, the owner heard a loud crack. The next morning he found that that the veneer had cracked right at the middle of the bottom rail. I replaced that bottom rail (not easy) with one made with a wood stave core and used 1/8" thick veneer instead of 1/4", and it has been fine now for several years.

Thick veneer over a very stable substrate is not a good choice for an exterior door, IMO.

John

[Malcolm Schweizer]

I built an exterior door with white oak exterior veneer over an LVL core, with ash on the inside, with T-88 epoxy. One night a couple of months after I installed the door, when it was really cold, like zero, the owner heard a loud crack. The next morning he found that that the veneer had cracked right at the middle of the bottom rail. I replaced that bottom rail (not easy) with one made with a wood stave core and used 1/8" thick veneer instead of 1/4", and it has been fine now for several years.

Thick veneer over a very stable substrate is not a good choice for an exterior door, IMO.

John

I agree with you. There is too thick and there is too thin. It’s a balancing act.

[Warren Lake]

old guy used 1/4 and 3/8". Some amount depends on your core and how its constructed. Thickest doors they did were six inches with a whole number of cores opposed to each other.

[Mel Fulks]

The old books say ,over 1/8th is a “ facing” , that means “ too thick to be veneer” so
“don’t use it for veneer”.

[Warren Lake]

the six inch doors had to last 300 years. He took a short cut once and got whacked for it.

[Tom M King]

Virginia Preservation, but I deal indirectly through the owner of the building. I think it may be dependent on who you talk to as to what they require you to do, but I have seen some pretty picky stuff. That said, they have also worked with the owner on some other things.

PVa has some strange ones that expect the impossible. They've always been pleased with anything they've ever looked at that I did though, after the fact.

The absolute strangest thing was some temporary doors I had up while we rebuilt the originals. The temporary doors were just plywood reinforced with some YP cross pieces and brackets to hold a YP 2x to bar the door. The four people visiting from PVa were three ladies probably in their late 80's and one man not much younger. They all absolutely raved about those plywood doors when there were many other things there that should have been right up their alley.

When I showed the the old plaster that I had repaired all the cracks in and put a skim coat on, they absolutely loved it but said that it was impossible to skim coat old plaster.

I absolutely love dealing with Preservation North Carolina. They go along with anything I want to do and love it. They call me once in a while for an opinion on something too.

The PVa ones can be a strange bunch. I'm in the middle of dealing with them right now on a dry stacked foundation they want done to look original but suggest using cinder blocks and bricks. The bricks are new bricks that supposedly look old, but to me they're nothing at all like the old bricks. One good thing about PVa is that they seem to have plenty of grant money available, but really oddly award it for stuff that doesn't really matter.

Are there tax credits still available in Virginia? The outfit I'm working with is tax free, so it really doesn't matter to them about whether something qualifies for a tax credit or not.

[John TenEyck]

The old books say ,over 1/8th is a “ facing” , that means “ too thick to be veneer” so
“don’t use it for veneer”.

Yes, and yet the Germans use veneers around 7 mm for some exterior doors. And the guy who mentored me on exterior doors used 1/4" veneer. I built a couple that way w/o issue, including one in very brutal conditions. All was OK, until the one with white oak.

It is, indeed, a balancing act. I now use 1/8" veneer over stave core construction. So far, so good.

John

[Larry Edgerton]

Malcolm. I top coat with automotive clears after the 207, first a clear adhesion promoting primer made for urethane bumpers, then several coats of a flexible clear like Sherwin Williams 7000 so it gets UV protection from that. Plus it is on the North side of the house, under a roof.

I have already built doors in this manner. The plywood is totally encased inside the door with epoxy. I have one that has been in the weather for 30 years and is still in perfect working order. The overlays are 3/4" thick and the edges of the ply are all buried under solid wood. Makes a nice solid 2 1/4" thick door.

My question was if using two species would be a problem, as the technique is proven with one. The entryway is trimmed in Padauk, so I want to match, but padauk would not look good on the outside and is too brittle fr outside duty in my opinion.

I think I will just try it, its just a door. If it does not warp fine, if it does I will make a new door. I get to experiment on my own house.

[Malcolm Schweizer]

PVa has some strange ones that expect the impossible. They've always been pleased with anything they've ever looked at that I did though, after the fact.

The absolute strangest thing was some temporary doors I had up while we rebuilt the originals. The temporary doors were just plywood reinforced with some YP cross pieces and brackets to hold a YP 2x to bar the door. The four people visiting from PVa were three ladies probably in their late 80's and one man not much younger. They all absolutely raved about those plywood doors when there were many other things there that should have been right up their alley.

When I showed the the old plaster that I had repaired all the cracks in and put a skim coat on, they absolutely loved it but said that it was impossible to skim coat old plaster.

I absolutely love dealing with Preservation North Carolina. They go along with anything I want to do and love it. They call me once in a while for an opinion on something too.

The PVa ones can be a strange bunch. I'm in the middle of dealing with them right now on a dry stacked foundation they want done to look original but suggest using cinder blocks and bricks. The bricks are new bricks that supposedly look old, but to me they're nothing at all like the old bricks. One good thing about PVa is that they seem to have plenty of grant money available, but really oddly award it for stuff that doesn't really matter.

Are there tax credits still available in Virginia? The outfit I'm working with is tax free, so it really doesn't matter to them about whether something qualifies for a tax credit or not.

Oh there are certainly tax credits, as well as grants. My house was built in 1880. I’m trying to get in on the grants myself. The project we are working on now has big tax credits and also is partly funded by grants.

[Joe Calhoon]

Yes, and yet the Germans use veneers around 7 mm for some exterior doors. And the guy who mentored me on exterior doors used 1/4" veneer. I built a couple that way w/o issue, including one in very brutal conditions. All was OK, until the one with white oak.

It is, indeed, a balancing act. I now use 1/8" veneer over stave core construction. So far, so good.

John

John, thick skins are fine over a solid wood stave core. If using LVL or Timberstrand type Cora then you need to use thin veneer. Myself I would not use 1/8” on an exterior door. Plenty of manufacturers do though.

[John TenEyck]

Malcolm. I top coat with automotive clears after the 207, first a clear adhesion promoting primer made for urethane bumpers, then several coats of a flexible clear like Sherwin Williams 7000 so it gets UV protection from that. Plus it is on the North side of the house, under a roof.

I have already built doors in this manner. The plywood is totally encased inside the door with epoxy. I have one that has been in the weather for 30 years and is still in perfect working order. The overlays are 3/4" thick and the edges of the ply are all buried under solid wood. Makes a nice solid 2 1/4" thick door.

My question was if using two species would be a problem, as the technique is proven with one. The entryway is trimmed in Padauk, so I want to match, but padauk would not look good on the outside and is too brittle fr outside duty in my opinion.

I think I will just try it, its just a door. If it does not warp fine, if it does I will make a new door. I get to experiment on my own house.

Larry, I made my front door with Sapele finished with Prolux Door and Window finish on the outside and maple painted white on the inside, over a stave core. Both veneers are 1/8". It's been fine for about 5 years now. No issues whatsoever.

John

[John TenEyck]

John, thick skins are fine over a solid wood stave core. If using LVL or Timberstrand type Cora then you need to use thin veneer. Myself I would not use 1/8” on an exterior door. Plenty of manufacturers do though.

Thanks Joe. I thought the Germans were/are putting 7 mm over a composite core?

John