Interior door construction

[Dave Squires]

I'm looking to build some interior doors for my house. These are 3'x8' single shaker style. I was planning on using 1 3/4" poplar for the stiles and rails and dado 1/2" MDF for the inside panel. I was going to attach the rails/stiles with a Domino 700.

My concerns are whether the poplar will be stable enough. The other idea is to still use poplar, but to laminate two pieces of 7/8" to help with any movement. Would really appreciate any suggestions for this style of door to help ensure stability over time. Thank you!

To add, these will be painted.


452333

[Jim Becker]

Properly dried tulip poplar is just as stable as any other hardwood, so IMHO, no worries there if you use quality materials. Soft maple is an option that's similar in cost (in my area at least) if you need to compare and choose an alternative.

1.75" is pretty thick for an interior door. If it's replacing existing, the stops and hinge accomodations in the opening will have to be rejiggered.

As to your build methodology, I'd be doing it similar to you with the DF-700 and 14mm Dominos. As an alternative, working with three layers of .5" material laminated permits easy full depth M&T without chopping out the holes while also making it easy to do the half-inch panel. That's how I did the door for our basement stairway in the kitchen (pre-Domino in my shop), although I used .5" BB for the panels. I made moldings to match other doors in the house and applied them inside the panel openings after the door was glued up and fully assembled. (I had to make this door because it was an odd size and not, um...square. The one for the powder room will be similar...odd side and not even close to square. I have to match the openings as they cannot be adjusted. Old house fun)

[Dave Squires]

Thank you Jim, I like the idea of doing .5", could just hold back on the center for the dado. I was considering also using an LVL (https://www.menards.com/main/building-materials/trusses-i-joists-engineered-lumber/laminated-veneer-lumber-lvl-strand-lumber/1-3-4-x-7-1-4-lvl-1-9e/1061080/p-1444438528942.htm) for the frame, with it being painted, maybe this could be a good cost effective way and maintain stability.

[Jim Becker]

LVL is going to be darn tough compared to poplar or maple...it's also murder on tooling and heavier than all get-out.

[John TenEyck]

Poplar is fine but soft maple is better as it won't dent as easily and paints great. Use quarter or rift sawn wood for the greatest stability. I would glue the MDF panel in the frame. The Dominos will hold the frame together, but the glued in panel will make the whole assembly incredibly strong. An alternative to MDF is PlumaPly It's 2 or 3 mm of HDF on both sides of a plywood core. Just as flat as MDF but much stronger and paints great.

John

[Richard Coers]

I'm looking to build some interior doors for my house. These are 3'x8' single shaker style. I was planning on using 1 3/4" poplar for the stiles and rails and dado 1/2" MDF for the inside panel. I was going to attach the rails/stiles with a Domino 700.

My concerns are whether the poplar will be stable enough. The other idea is to still use poplar, but to laminate two pieces of 7/8" to help with any movement. Would really appreciate any suggestions for this style of door to help ensure stability over time. Thank you!

To add, these will be painted.


452333
Why so thick? The door is really 8'? You have 10' ceilings? Width of the rails and stiles will be a concern for the stability. Go too wide and you'll get boards that may be closer to the pith and those will move more.

[Jim Dwight]

1 3/4 is normal for exterior doors, 1 3/8 is the most typical thickness of interior doors. As has been mentioned, if you hang a 1 3/4 inch door in a jamb made for a 1 3/8 you will at least have to move the stops (if they are not intergral, if they are you have to change the jamb).

I made one door like you describe and illustrate. It was the interior door to my shop. I made the rails and stiles from construction lumber planned down to 1 3/8. I did not have a domino so I used traditional mortise and tenon joints. The mdf panel was in a dado as you plan but I also put a shop made molding around the panels that dressed them up. Construction lumber if frowned on by many but it worked fine for me. It is often not as stable as good hardwood, however.

[David Kumm]

I'm in the minority but I prefer 1.75" interior doors. The feel and heft on ball bearing hinges is hard to beat. If you keep your house reasonably temp and humidity controlled, solid wood should be a non issue, laminated or not. I'm looking at 3-8 doors I made 20 years ago for my office and they still look new in spite of peoples best efforts to screw them up. I would go with maple. you can dent poplar with a finger nail. I would also make sure you are happy with the 1/2" panel vs the 1.75" frame. I like more panel thickness but that is because all doors you buy cut costs by making panels thinner. Anything thicker than 1/2" might be too a lot of weight though. You also want to size the width so it looks appropriate to the hardware. I think a 3.75" backset looks better on that size door but you need5-5.5" frame to make it look right. I also use 4-4" ball bearing hinges on doors that size. They don't need to be as good as Hagar but at least similar to Emtek in quality. Dave

[David Zaret]

i agree with dave on 1.75" doors - that's my go-to, i like the heft and feel. for construction, i've had really good success with LVL cores, i use Timberstrand, edge it with solid stock, and veneer it with shop-sawn veneers. the doors are incredibly stable - they don't move at all. construction can be either domino 700s if i'm covering the edges with a moulding, or doing a straight shaker, or cope and stick with the Zuani set (or freeborn set). i cannot speak highly enough of the end result of doors made with timberstrand - they never, ever move.

-- dz


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[David Kumm]

Beautiful David. What do you buy, the framing 2x6 or headers with 1/8" veneer? How thick to you band the edges, depending on profile? I've got some Hickory doors to make and they get so heavy I usually cut them down to 1.5". this might be an alternative unless I get some really nice 8/4 Hickory but that is getting hard to source locally. Do you run into issues with the solid edges telegraphing through the sides and seeing it under the veneer? Is the LVL hard on a WB or planer? I'm assuming you glue the edges, run the LVL through either machine to get flush, put on the veneer after that? Dave

[Dave Squires]

i agree with dave on 1.75" doors - that's my go-to, i like the heft and feel. for construction, i've had really good success with LVL cores, i use Timberstrand, edge it with solid stock, and veneer it with shop-sawn veneers. the doors are incredibly stable - they don't move at all. construction can be either domino 700s if i'm covering the edges with a moulding, or doing a straight shaker, or cope and stick with the Zuani set (or freeborn set). i cannot speak highly enough of the end result of doors made with timberstrand - they never, ever move.

-- dz


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That sounds good. Another idea I was considering is LSL (https://www.menards.com/main/building-materials/trusses-i-joists-engineered-lumber/laminated-veneer-lumber-lvl-strand-lumber/lp-reg-solidstart-reg-lsl-2-x-6-laminated-strand-lumber/1068518/p-1444438204228.htm). Could just go 1.5", but this would be pretty cost effective and I can't imagine any deflection at 8' with these as the frame. I was planning on going with soss hinges (3x 218). This would end up being about a 75lb door, which should have a pretty good feel to it.

[David Zaret]

dave - i buy the 2x6 timberstrand and hack it up as needed to make cores the size i need. if i need wider pieces, i just glue it together.

to machine the timberstrand, i take it raw, rip off the factory edge on the slider, clean up the other edge... and glue on some solid stock - this is rough at this point, just get it glued on. once dry, i slip a nasty set of tersas in the jointer and face joint the whole sandwich flat, then plane it down, again with nasty tersas that i hold back for precisely this type of thing. it machines just fine.

i run it through the wide belt with 60 grit just to open up the surfaces to get a solid glue bond... then i vacuum press on my shop-sawn veneers. then, either cope and stick on the shaper, or size and 14mm dominos, typically with thickened epoxy. the doors are solid, heavy, stable, flat. the edges are all solid wood, the timberstrand is buried in the cores. i've made... 20(?) this way with great success.

here's a shot of the joinery of one of the cherry doors i made with the zuani set - i think this was 1 3/8":

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[David Kumm]

I probably wouldn't want to run my Porter jointer over it but the ESTA in my 8" jointer would be OK. I've never had a door warp but worry that the wide rail is the weak joint. I've never had one fail but the TS or laminated core idea has tempted me. Do you make the loose tenons from TS or hardwood if not using Dominos? I run a Bacci and would guess a carbide end mill is better than HSS in that stuff.

What glue to you like for the veneer. I've used Resorcinol ( SP ) powder from Woodcraft and it likes to curl up the veneer vs even a slightly thinned slow set yellow glue. I also use epoxy for most doors unless I'm assembling the center rails and stiles and have more time. The outer with the loose tenons works best with epoxy. Dave

[David Zaret]

i think that any carbide tooling is fine. the timberstrand is rough, but probably easier on tooling than particle board. i haven't seen an issue with carbide hitting it. for glue, i really like two-part urea resin for doors, a great solution. better than epoxy for the veneering. but sometimes i use thickened epoxy for the loose tenon part of it because i can easily mix a small amount without measuring.

specifically, the two-part from vac-u-press (unibond 800, with the thickener) is my go-to. it''s wonderful stuff. if you keep it refrigerated it lasts a long time.

for the tenon stock, i use the largest dominos (14mm thick) and they are incredibly strong. i think that any comparable hardwood tenon would be just fine. these doors will absolutely outlive me, my kids, their kids.. unless somebody proactively rips them out. those joints aren't failing.

[mreza Salav]

I made 31 doors and jambs for them for our house (documented in threads here) out of Maple at 1.75" thick with 3/4" thick plywood panels gluing. These were stained. After 6 years of use I still love the end result. I would use plywood instead of MDF and wood add a middle rail.

[Larry Edgerton]

1 3/4 Doors on my house, ash. I do a lot f custom doors and most interior doors are 1 3/4" unless they are replacements for existing. Have done a lot of doors out of Tulip, no problems. I do a base coat of thinned west system on poplar doors to toughen the surface before primer.

I do disagree that you need bearing hinges. You need better than the box store junk for sure, and I have great success with cast iron hinges from Renovators. They work like magic, never have wear issues and are WAY better looking.

[David Zaret]

1 3/4 Doors on my house, ash. I do a lot f custom doors and most interior doors are 1 3/4" unless they are replacements for existing. Have done a lot of doors out of Tulip, no problems. I do a base coat of thinned west system on poplar doors to toughen the surface before primer.

I do disagree that you need bearing hinges. You need better than the box store junk for sure, and I have great success with cast iron hinges from Renovators. They work like magic, never have wear issues and are WAY better looking.



tightening up the poplar with epoxy is a great idea. how do you thin the epoxy for this application - acetone?

[David Kumm]

Good to hear from you Larry, still got the big shaper?

I'm tempted to try the TS at least for the wide rails on a 6 panel door. Stiles stay pretty stable unless you fit the door tight in the summer which is a different issue. Would anyone estimate the extra work vs the cost of solid wood assuming non exotic stuff like Cherry, maple, walnut etc. Dave

[John TenEyck]

Good to hear from you Larry, still got the big shaper?

I'm tempted to try the TS at least for the wide rails on a 6 panel door. Stiles stay pretty stable unless you fit the door tight in the summer which is a different issue. Would anyone estimate the extra work vs the cost of solid wood assuming non exotic stuff like Cherry, maple, walnut etc. Dave

For me the cost of solid wood is nothing compared to how much time it takes to make a stave or LVL / veneered door. Most of the doors I've made are stave core/veneered, both interior and exterior so I'm pretty efficient at the process, which is very similar to what DZ described. It has to take me at least 5 or 6 more labor hours to make a stave core/veneered door. In addition, you have the WIP time waiting for the glue to cure in the vacuum bag. Great doors, which is why I make them that way, but it's a time sucker for me.

FWIW, be careful using LVL cores for an exterior door. I had the veneer split on one wide bottom rail on the exterior side. The veneer wanted to shrink but the core wouldn't let it so it split. After that learning lesson I only use stave core or solid wood for exterior door rails.

John

[David Kumm]

I'm curious as to the benefit of the extra time. I understand that certain wood, or certain designs benefit greatly from the stave, TS, type of construction. More traditional doors with panels and center stiles don't seem to me to be worth the effort. My raised panels are 1.5" thick with 1/2" tongues and I would think a 3/4" or greater flat panel would have even more structure to it. I'm not second guessing, just want to know if there are benefits I'm not seeing. Dave

[Joe Calhoon]

Lot of acceptable ways to build interior doors. 1.75” is the way to go for a custom interior. Sometimes thicker on tall and wide. I prefer to go solid wood whenever I can get good material. 2 piece lamination is a bad idea. Did some of that early on...
I mostly use real wood stave cores when I need stability or grain matching and working with unstable material. Rails I Mostly use solid wood. LVL or timber strand is a bad idea for any wide rail unless you use very thin face veneer. With walnut and cherry sometimes a stave core allows for getting rid of sapwood. Generally though I prefer well seasoned and well faced solid wood.

We used timberstrand on a few interior projects and did not care for it. Hard maple and VG fir are 2 species I would not put on timberstrand.
Timber strand is easier to build compared to solid wood for engineered stiles but I have a dislike for man made materials in my doors. A lot of companies are successful using it though. I occasionally use LVL for exterior door stiles when working with difficult materials like barn wood.

[David Zaret]

john - i agree with you it's a time sucker, for sure. the reason i switched from solid wood to LVL was movement. i built 10 or so doors, carefully selected stock, did careful glue ups... and yet, i'd say on half of them, they moved, even a little. 1/16" of bow along a stile is enough to annoy me. for my interior LVL core doors, i'm yet to see anything move a hair. more work, for sure. good info on the exterior use, thanks for that.

joe -- a while back, you gave jim biddle a sample of a stave core product you use... i don't know where you get it, or what it is, but if i could buy that stuff, i would do it in place of the timberstrand. it's simply not a product i've ever seen. LVL is, generally speaking, a poor compromise to a commercial solid stave core... i simply don't know where to find such a thing.

--- dz

[Mel Fulks]

Have to disagree on 1 and 3/4. It’s okay in some places ,I think it depends on the situation . Right now a lot of clunky ,everything must
be asymmetrical stuff is the style. So fat doors are are okay. Jefferson’s old house has doors 1and 1/4 on inside. Been there a long time .
But that’s a house where anything fat ...never had a chance !

[Joe Calhoon]

Very true in historical work Mel. Years ago we did a new house that was a exact shaker reproduction. The architect was associated with one of the Shaker villages. The interior doors were all called out at 1 1/8”. And exterior at 1 1/2”.

[Joe Calhoon]

joe -- a while back, you gave jim biddle a sample of a stave core product you use... i don't know where you get it, or what it is, but if i could buy that stuff, i would do it in place of the timberstrand. it's simply not a product i've ever seen. LVL is, generally speaking, a poor compromise to a commercial solid stave core... i simply don't know where to find such a thing.

--- dz

Dave, look at the barn wood core. It’s a LVL designed for doors with vertical grain and supposedly drier than construction LVL. It comes in 36”X 98” sheets in two thickness. I get it from National Wood Products. They are tight lipped about the product name. I think it comes from the Northwest. It’s straight, I usually just band it, flush trim and abrasive plane before gluing the skins on.

[Joe Calhoon]

452412
here is the picture, couldn’t insert it in the other post for some reason

[Brad Shipton]

If you have access to a glulam supplier that makes for a nice core as well. A bit lighter too. Joe has shown off some BauBuche before as well. That would be great, but not easy to find.

Was it easy to find hardware for those 1" passage doors or was that custom as well?

[Mel Fulks]

Joe ,I remember one really large job where I actually changed the couple’s choice. All the doors were spect. 1 and 3/4 “ , I told them it was
too thick for inside. They said the architect was afraid we couldn’t make them all straight enough. Told them to bring any 1 and 3/8ths doors
back that that were not straight enough ,and I would stop whatever I was doing and replace it. And I was just an employee !

[Jared Sankovich]

Count me in the thicker door is better camp. I prefer 1.75 interior doors. I also prefer 1.125" cabinet doors.

[William Hodge]

I make solid wood through mortise and tenon doors. I copy existing for old buildings. Custom cope and stick and custom panel profiles are typical. I built my first door in 1985.

Poplar works well for interior doors. Knowing the wood in its rough state, and being able to pick good wood for stiles, is crucial. Being able to see the finished product in a rough board makes pulling stock easier. Go for the stiles first, cut the bad ones up for rails. Never make the top rails and mid stiles wider than the stiles. The bad stiles have to go somewhere.

Wood will move, wood will check, wood is wood. Planning for movement and accepting wood as a variable raw material makes it easier to accept a product that looks like wood, a variable raw material.

A full or partially plastic door will be more appealing, just like a laminate floor will look perfect, compared to a wood floor. Wood grain plastic laminate table tops will never check. 4' x 8' sheets of wood grain paneling were a familiar feature of 1970' rec rooms. You need to decide whether you want a plastic door or a wooden door.

[Michael W. Clark]

452412
here is the picture, couldn’t insert it in the other post for some reason

How thick of a face veneer do you typically use? I’m doing some doors that are barn door arrangement but not the rustic style. I think I almost got the veneer too thin on the stave cores. I’m doing loose tenons, wish I had done a stub tendon instead. Panels will be solid, held in with applied moldings.

The doors are on our master bath, its a big room so moisture not a huge issue. Two doors to cover opening, 100" x 60". They slide apart in the middle, couldn't do one door due to obstructions. Here is a fit-up of one half. Need to do mortises and tennons but procrastinating as I don't want to mess it up.

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[Larry Edgerton]

Good to hear from you Larry, still got the big shaper?

I'm tempted to try the TS at least for the wide rails on a 6 panel door. Stiles stay pretty stable unless you fit the door tight in the summer which is a different issue. Would anyone estimate the extra work vs the cost of solid wood assuming non exotic stuff like Cherry, maple, walnut etc. Dave


Hi David K. Yes I still have the beast, love the thing. Still, getting old and thinking of getting one with at least some readouts. Also was wondering if the sliding table add on that SCMI sells in Europe is available here, gave up on finding a factory Unitronix tenoning table. The double spindle thing is really handy, but really at 7'6" long it is just two shapers with one top.Was about to buy a new SCM but got a divorce instead. Bought her out of my house that I built and paid for. Stuff happens....

Dave Z. Yes. I called West System and told them what I wanted to do and that is what they recommended.

I have built a few exterior doors with a baltic birch or appleply core through the whole door with one sided wood faces applied to both sides in a bed of West System. Very heavy, thick but extremely durable. I do a West soak on the face side with 207 hardener before a base coat of automotive clear flexible adhesion promoting primer followed by an automotive clearcoat. No failures in 35 years of Northern Michigan exposure. Expensive process, but for those times when money is no object.....

I love reading all you guys different solutions................

[Peter Kelly]

Very true in historical work Mel. Years ago we did a new house that was a exact shaker reproduction. The architect was associated with one of the Shaker villages. The interior doors were all called out at 1 1/8”. And exterior at 1 1/2”.What sort of period-consistent hardware works with an 1-1/8" passage door? Even those black rim latches from Acorn require at least 1-3/8". Was this also a custom thing?

[David Zaret]

for shop-sawn veneer, i target 0.050" thick.





How thick of a face veneer do you typically use? I’m doing some doors that are barn door arrangement but not the rustic style. I think I almost got the veneer too thin on the stave cores. I’m doing loose tenons, wish I had done a stub tendon instead. Panels will be solid, held in with applied moldings.

The doors are on our master bath, its a big room so moisture not a huge issue. Two doors to cover opening, 100" x 60". They slide apart in the middle, couldn't do one door due to obstructions. Here is a fit-up of one half. Need to do mortises and tennons but procrastinating as I don't want to mess it up.

452431

[Joe Calhoon]

What sort of period-consistent hardware works with an 1-1/8" passage door? Even those black rim latches from Acorn require at least 1-3/8". Was this also a custom thing?

That job was more than 25 years ago. If I remember the interiors were forged thumb latches and mortise locks on the exterior. No tubular latches. Ball and Ball maybe. What I remember most from that job was the doors had a small bead detail on the sticking. Times were lean then and I decided to apply the bead instead of having custom cutters made. Huge mistake, what a tedious job applying hard maple beads to both sides of the doors!

[Joe Calhoon]

How thick of a face veneer do you typically use? I’m doing some doors that are barn door arrangement but not the rustic style. I think I almost got the veneer too thin on the stave cores. I’m doing loose tenons, wish I had done a stub tendon instead. Panels will be solid, held in with applied moldings.



Being in the custom door business we end up with many different constructions that require creative solutions on making stiles.
like I mentioned, solid is my choice when proper materials are available. Typically 1 3/4 interior doors with a stave core get 3mm skins. The skin edge usually disappears with edge easing. Sometimes on thick wallet jobs the edges are mitered into the skins. (Much labor to do this.) with knotty white oak and cherry where the material is only available in 4/4 sometimes we do a 3 layer stile with thick faces and a thin core and mitered outside edges. This knotty material can be problematic doing 3 mm skins.

I rarely do exterior doors with skins because I dislike glue joints to the weather. If I do use skins in this application they are thick 7 to 8mm.

[John TenEyck]

As you can see by the prior responses, there is no hard and fast rule for veneer thickness, especially for interior doors. That said, to stand up to hard use I wouldn't go less than 1/16", and I see no reason to go thicker than 1/8". Sometimes you have to adjust the thickness of the veneer if the core comes out a little thinner than your target. So if my core came out at 1-3/16 instead of the 1-1/4" target I would make the veneers 3/32" thick. Why would the cores come out thin? Well, sometimes there is a bit of bow in them after glue up and by the time you joint and plane them flat they are a little under target. So you can either start over and make new ones or adjust the thickness of the veneer and use them. I've chosen the latter so far w/o problems.

John

[Mel Fulks]

And there is a good reason for the veneer to not go over 1/8”....because it wouldn’t be a veneer anymore ,It would be a “facing”.
So anytime something is impossible....Don’t Do It !!

[David Zaret]

we really need a "Like" button on SMC.

[David Zaret]

this weekend i find myself making a 1 3/4" service door in cherry. here's a shot of the stiles, ready for veneering. i know that others (with much more experience and wisdom than i have) have had issues with timberstrand, but thus far, and in lieu of other good available core options, it serves me well.

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[John TenEyck]

I built a couple of exterior doors with LVL cores. I think it's fine as long as the stiles aren't too wide nor the veneer too thick. As I mentioned earlier, I had some 1/4" white oak veneer split on a 13" wide bottom rail that had an LVL core. Since that experience, I've gone back to wood stave core construction. But for stiles I think it's fine.

John

[David Zaret]

here's a shot of the door end joint:

453404

[John TenEyck]

That looks mighty fine, David.

John