Is Baltic birch plywood stable enough for interior slab doors?

[Ken Cobbing]

Hi all,

I am in the finishing stages of a total bathroom remodel. This includes replacing two pocket doors and one swinging door.

The replacement doors will be simple stained slabs so as to match the rest of the 1960s home.

I had considered just ordering lauan-veneered solid-core slabs (about $100 each). But I'm curious: is Baltic birch plywood stable enough to make an 80" tall slab door?

It seems like going with Baltic birch for the doors would be less expensive and higher quality compared with a manufactured solid-core door, and not very much work. In order to make a 1-3/8" thick door, I would need to glue two pieces of 18mm (~3/4") plywood together to arrive at a finished thickness of 36mm (1.42"). I think that gluing two panels together should result in a very flat panel, but I've never attempted anything like this before. What do you all think?

Thanks for reading :)

[Mike Kees]

You would need a flat surface for the glue up. I think I would just buy the slabs pre made. Can not see this being cheaper in the end.

[Andrew Seemann]

I don't think baltic birch would be stable enough for what you want to do. Event though they are solid and cross laminated, birch itself is not very stable. Large and long pieces of baltic birch plywood almost always have some cup or warp to them. Laminating might cancel that out, or it could double it. The other think to think about is how heavy two sheets of laminated birch would weigh.

Honestly the most stable solution is probably a hollow core door, basically a torsion box. You could take two pieces of stain grade hardwood 1/4" plywood (American made so it has a stable core like poplar or fir) and glue them to a frame to get 1 3/8". I did that to replace a set of old fashioned hanging accordion-type garage doors, and they have held up just fine for the 5 years they have been in service.

You could also just break down and buy a door. No shame in solving a problem with your checkbook:)

[Gary Ragatz]

Locally, Menard's is selling 4x8x3/4" baltic birch sheets for $62.29 (after a mail-in rebate) - can't see that beating the solid-core slabs at $100, even if your labor is free.

I've used commercially available solid-core doors - both as doors and as worktable tops. Never any complaints about quality/durability.

[johnny means]

Do you have a vacuum press? If not, clamping up a flat panel is going to be tricky?

[David Zaret]

no. don't do it. unless you have a vacuum press, use urea resin glue, use multiple sheets of thinner material... it won't stay flat. if you have the ability to laminate/veneer, consider using a core like timberstrand and veneering it. that stuff is stable, and absolutely won't move. i've made a ton of doors with timerstrand cores, and not a single one has moved at all. nearly everything i've made with baltic moves at least somewhat seasonally.

good luck with the project.

-- dz

[Ken Cobbing]

I don't think baltic birch would be stable enough for what you want to do. Event though they are solid and cross laminated, birch itself is not very stable. Large and long pieces of baltic birch plywood almost always have some cup or warp to them. Laminating might cancel that out, or it could double it.

Thanks Andrew. This is what I suspected. But also, I didn't consider that laminating could actually make the panel *less* flat. Makes sense.



The other think to think about is how heavy two sheets of laminated birch would weigh.

The door sizes are all 24 x 80 (small!). Each would take just less than a single 4x8 sheet which weighs about 85 lb. The pocket door track I installed is rated at 200lb. I think a manufactured solid-core door in the same size weighs about 75 lb, so I don't think weight is a consideration.



Honestly the most stable solution is probably a hollow core door, basically a torsion box. You could take two pieces of stain grade hardwood 1/4" plywood (American made so it has a stable core like poplar or fir) and glue them to a frame to get 1 3/8". I did that to replace a set of old fashioned hanging accordion-type garage doors, and they have held up just fine for the 5 years they have been in service.

You could also just break down and buy a door. No shame in solving a problem with your checkbook:)

Building a hollow-core door could work, but I'd rather have a solid-core door for noise insulation. I think your advice to just buy some manufactured solid-core slab doors is probably what I should do.


Locally, Menard's is selling 4x8x3/4" baltic birch sheets for $62.29 (after a mail-in rebate) - can't see that beating the solid-core slabs at $100, even if your labor is free.

Thanks, Gary. I normally pay about $50 per 4x8 sheet of Baltic birch. Since the doors are 24" x 80", I could get a full door from a single sheet. Still, about $100 per manufactured door (Lowes) is pretty cheap, so I guess price isn't too much of a consideration.



I've used commercially available solid-core doors - both as doors and as worktable tops. Never any complaints about quality/durability.

I agree completely, except in the case of these "flush" slab doors. The lauan veneer is razor thin and damages fairly easy. The reason I'm replacing all three original bathroom doors is because they all had substantial damage in the veneer. I figured the thick plies found in Baltic birch could be a solution for that.


Do you have a vacuum press? If not, clamping up a flat panel is going to be tricky?

Thanks, Johnny. No, I don't have a vacuum press. And after thinking about it more, I agree that trying to glue up a 24" x 80" panel and getting it flat would be quite difficult considering I haven't every attempted something like this before.

I think I should just go with some manufactured doors and try my best to protect the thin veneer with a good finish.

[Mark Gibney]

David any chance you can give me a link to the timberstrand product you're talking about? I'd really like to look into it.
Thanks

[David Zaret]

hey mark,

timberstrand is basically LVL material, without the waxy coating. it's "engineered lumber" used for ultra-straight and strong 2x stock for interior construction. there are alternatives - i think that Menards has a competing product. timberstrand in particular is a Weyerhaeuser product:

https://www.weyerhaeuser.com/woodproducts/engineered-lumber/timberstrand-lsl/

i was fortunate to find it available at a local lumberyard - this isn't necessarily a big-box product, but again, i think menards has a competitor.

i use it as door cores, and i machine it as i would any lumber core. it's a bit harder on the knives, but worth it. most of the time i use shop-made veneer over it, but i have used "thick" commercial veneer. here's one of the many doors i've made with timberstrand, this one clad in cherry:

444884444885

[Frederick Skelly]

hey mark,

timberstrand is basically LVL material, without the waxy coating. it's "engineered lumber" used for ultra-straight and strong 2x stock for interior construction. there are alternatives - i think that Menards has a competing product. timberstrand in particular is a Weyerhaeuser product:

https://www.weyerhaeuser.com/woodproducts/engineered-lumber/timberstrand-lsl/

i was fortunate to find it available at a local lumberyard - this isn't necessarily a big-box product, but again, i think menards has a competitor.

i use it as door cores, and i machine it as i would any lumber core. it's a bit harder on the knives, but worth it. most of the time i use shop-made veneer over it, but i have used "thick" commercial veneer. here's one of the many doors i've made with timberstrand, this one clad in cherry:

444884444885

David, do you think this material can be face glued together with Titebond-type glues? I'm wondering if it could be laminated into a workbench top instead of 2x4s.

Thank you,
Fred

[roger wiegand]

Are these prices for real? 18 mm Baltic birch ply is currently selling for $118 for a 4x8 sheet here (mostly it comes 5x5 though) We don't have Menards, but I've never seen actual Baltic birch or even a similar North American product like Appleply at Lowes or Home Depot. They had a similar looking product that I bought once, but it was garbage, full of voids and made from some soft white wood.


https://sawmillcreek.org/images/misc/quote_icon.png Originally Posted by Gary Ragatz https://sawmillcreek.org/images/buttons/viewpost-right.png (https://sawmillcreek.org/showthread.php?p=3069815#post3069815)
Locally, Menard's is selling 4x8x3/4" baltic birch sheets for $62.29 (after a mail-in rebate) - can't see that beating the solid-core slabs at $100, even if your labor is free.



Thanks, Gary. I normally pay about $50 per 4x8 sheet of Baltic birch. Since the doors are 24" x 80", I could get a full door from a single sheet. Still, about $100 per manufactured door (Lowes) is pretty cheap, so I guess price isn't too much of a consideration.

[Steve Rozmiarek]

I think you'll find that the prices are off a wild right now, a simple slab door here is actually cheaper than a sheet of BB ply.

[Jim Becker]

Provided you buy quality pieces and have an absolutely flat surface to do the glue-up, preferably with some method to "press" the workpiece while the glue sets, you can be successful. Do keep in mind that most true BB is only 60" long and you're making 80" doors according to your description. Nominal 4x8 BB is made, but it's a lot harder to find and you do NOT want a lot of the lower cost "multicore" sheet goods that are on the market, especially at box stores.

Steve does make a good point, however....it may actually be more cost effective to source a pre-made solid slab door than to make it from raw materials, especially if it's a "normal" sized door.

[Ken Cobbing]

Are these prices for real? 18 mm Baltic birch ply is currently selling for $118 for a 4x8 sheet here (mostly it comes 5x5 though) We don't have Menards, but I've never seen actual Baltic birch or even a similar North American product like Appleply at Lowes or Home Depot. They had a similar looking product that I bought once, but it was garbage, full of voids and made from some soft white wood.

I think pricing for Baltic birch varies greatly depending on region. For 18mm, I last paid $32 per 5x5 and $51 per 4x8. Technically, this was for Russian birch. I have never seen anything claiming to be Baltic birch at a big box store.

I'll bet you didn't know that you are located just down the street from the American sales contact for "the" manufacturer of Baltic birch, Riga Ply, with mills in Latvia, Estonia, Lithuania, and Finland. Give them a call and ask about pricing:

https://www.finieris.com/en/products/plywood/raw-plywood/riga-ply

Riga Wood North America Inc.
1309 Beacon Street, Suite 315, Brookline, MA 02446, USA
Phone +1 774 400 4111
E-mail: ekerijs@rigawood.com
(ekerijs@rigawood.com)
I'm very curious about what pricing is like for this "true" Baltic birch. Post here or send me a PM if you find out :)

[roger wiegand]

No, I didn't know they were in Boston. I'll ask, I doubt that with my consumption of a half dozen sheets a year I'll have much luck buying directly from the importer! I go to Boulter Plywood for anything where I need to be sure of quality. I'm sure they are not the cheapest, but they always have what I need and it's always first rate. But a factor of 2-3 is enough to get me to look elsewhere!

In answer to the original question, for the time, trouble and money I'd definitely go with a store-bought solid core door. If you live near Boston there is a place called Builder's Supply in Peabody that has the best prices around on doors, really cheap if you can use one of their returns.

[mark mcfarlane]

$51 for a 4*8 sheet of real baltic birch is amazing. Is that the pre- or post-Covid-19 price?

Last week I paid $42 for a sheet of 5/8" BC plywood. I was astounded at how expensive it was. I needed a temporary front door for a neighbor's house. Even OSB was something like $30 for a 1/2" sheet.

[Frank Pratt]

There are several grades of BB plywood, so prices vary by grade. But $51 for an 18 mm, 4x8 sheet was almost certainly not Baltic Birch, unless it was damaged stock. I've seen "BB like" plywood in 4x8, but not the real thing.

[Ken Cobbing]

@Mark: Those prices were pre-Covid, but last week I called and checked on pricing and prices do not seem to have changed (although I only checked on 5x5 sheets, so I don't know if the price for 4x8 has changed). I have also purchased BC and CDX plywood in recent weeks and those prices have gone through the roof so I was expecting the same for the Baltic birch and was pleasantly surprised that it has remained stable.

@Frank: the grade of the plywood I have purchased is B/BB, which I believe is the highest grade available. It is "real" Russian birch, with Cyrillic characters stamped on the factory edge. No voids and fantastic quality IMO. I purchase it in both 5x5 and 4x8 sheets and they are stamped from the same Russian mill. The 4x8 sheets actually cost more per sq ft than the 5x5 sheets.

I'm not surprised that your pricing is higher being landlocked in Alberta (beautiful country). My guess is that pricing is much lower in the USA, and substantially lower for those close to Eastern seaports. But I'm certainly no expert.

[mark mcfarlane]

Thanks Ken for the clarifications. Those are really good prices.

[Frank Pratt]

Ken, that does make sense. We pay well over $100 for 4x8 Russian birch, but that is with our funny money. I've never actually used the 4x8, so can't comment on the quality. It's so much more expensive/sq. ft. than the 5x5 Baltic birch & I've not had a project that needed the longer dimension.

[Malcolm Schweizer]

I have used Baltic Birch extensively in furniture building, and I also build high-end mahogany doors. The problems I see with your idea are as follows:
- Weight: it’s going to be really heavy for a hinged door. Pocket doors won’t be as big of a deal.
- You said you wanted to stain them to match other doors. Baltic Birch is not friendly with stains. They don’t penetrate well, and leave you with a splotchy look and it is hard to get a good color. It always looks like stained birch.
- You need a solid wood to mount your hinge to. I would shy away from mounting a hinge into the edge grain of any plywood. A solution would be to rabbet in a solid edge on both sides- so it doesn’t look like you laminated plywood.
- Acoustical qualities may not be favorable. It would be a very hard door and reflect sound. Not a huge deal, but something to consider.

As for movement, I think you would be OK with a laminated door. I would build a flat table and use jointed 2x4’s clamped along the top of the glueup every foot or maybe 18”. Clamp it down on either side to pull the two tight together. I am more concerned with warping than movement, with my interpretation being movement is expansion and contraction, and warping is distortion. Again, I would frame the edges at minimum to counter this. A better idea is build a frame out of a similar hardwood, and groove the inner edges for a single 3/4” panel of birch. That would be one solid door.

Edit: Like this, but rabbet or groove in a ply panel. These were glass doors. We rabbeted in the glass and made a trim piece to hold the glass in.

444969

[johnny means]

- Weight: it’s going to be really heavy for a hinged door. Pocket doors won’t be as big of a deal.


444969

I can't say I've ever run into a problem with doors being to heavy and I've made doors with three figure weights. Most clients like the heavier doors.

[Tom M King]

Anytime I was building cabinets for one of my houses, we'd rip it as it came off the truck, or trailer first thing. Saved a lot of handling whole sheets.

I've built a few doors out of two layers of 3/4" cabinet Birch plywood. I parked a wheel of the truck on the middle for clamping. Those doors, in our house in kneewalls upstairs, are still good after 40 years. They're only about 6' tall, but some taller I don't would make a lot of difference.

[Mark Gibney]

Thanks David, I'm going to try to get some locally.
I make benches and TV consoles using PSL beams - I wonder if this is essentially the same stuff?

[Tom M King]

The screw size for house door hinges is no.9. You can get them off Amazon in 2-1/4" length, in your choice of finish. We have had any issue with the hinges on those doors, all the years it took for our children to get to the point that they are grown, and gone, with daily use. I used 4" door hinges for exterior doors, since the doors are 1-1/2" thick.