How to Install French Doors
"Why are there so many questions and complaints about door install? I believe that door installation—and most carpentry or tradesman projects for that matter—requires a level of abstract thinking."
My good friends behind the counter at Dunn Lumber tell me that one question in particular keeps popping up: How do I install a door? The truth is, there's a lot of information out there on this subject and some of it may seem conflicting. I've seen lots of different approaches that provide some great information, but on the flip side, there is some not-so-great information. Some posts leave out steps from an install process, leaving the reader confused. There are many kinds of doors and many kinds of applications, so what's the solution?
I recommend creating a basic start-to-finish method and sticking with it consistently.
I can sometimes go an entire year without working on a house built after 1915. My company, Westbrook Restorations, works mostly with historic homes, so I consistently use an approach that works well with all the adverse conditions I have to deal with to make a door work well and look good.
What I'm going to focus on today is what I've learned over my 30-year career as a master carpenter. Our video on the double-door install isn't really a how-to video, as much as an opportunity to show that a door can be installed in a 100-year-old wall where there previously was no opening without patching the lath and plaster. It can be done!
Mind the Gap
The most common complaint my good friend Duane gets from contractors about double doors or "French" doors as I have gotten in the habit of calling them, is that the gap in the middle is too big or too tight and the doors don't flush out at the bottom. These days, Duane is a second-generation door expert that manages a major door supplier here in Seattle. For me the complaints beg the question: Why is he even getting these complaints? Isn't it just a matter of shimming and adjusting the doors and jamb so everything lines up?
Doors are not the easiest thing to install and do require a level of abstract thinking with all the interconnecting variables involved. There are so many different types of doors, from interior to exterior, out-swing to in-swing, composite to metal to wood. There are different thresholds to consider, and weather stripping, and—well, the list goes on!
You may already know that the wall applications are different as well. There might be a bow in the king stud, or the bottom of the wall doesn't line up in with the other side of the opening, or perhaps the wall is out of plumb or floor out of level. Of course, seemingly to complicate things, it seems that every carpenter has a different way of approaching and visualizing the install, and some who have installed many doors may have the thought process so engrained in their technique that installation becomes natural and effortless!
Abstract Thinking
So, back to the question above: Why are there so many questions and complaints about door install? I believe that door installation—and most carpentry or tradesman projects for that matter—requires a level of abstract thinking. As tradespeople, we do it every day. It's difficult, if not impossible, to define all these variables in an all-inclusive how-to video or single lesson.
This is precisely why I have a lot of respect for experienced tradespeople all over the world who have that unexplainable ability to go beyond basic installation commonalities and into the realm of adjusting to the unique variables for the good of the operation. If you're just starting out, or you're experienced and really want to up your game, my advice is to learn all the basics you can, be consistent, and build on that foundation. Watch an experienced craftsperson and how he moves. Find a mentor who can answer all your questions or take you under her wing. Watch videos and read books. Don't stop learning. I'll never forget what an old craftsman told me once: "The day I stop learn'n my craft, I'll be six feet under!"
With all that said, here are a few tips and tricks to keep in mind when setting any door:
Tip 1: Check the Opening for Plumb
Check the opening for plumb—not just the rough opening, but the wall itself. Do the bottom plates line up? What about the floor? Is it level? Learn what the opening is telling you so you can make a decision as to how you will set the jamb. If you can move a bottom plate a bit, that's okay because it will make setting the door easier. Don't start wailing away with a sledge on a 100-year-old antique wall with lath and plaster unless you want to pay to patch plaster! I'm just saying: Common sense has a roll to play.
Tip 2: Use a Flashing Pan
If you're setting an exterior door, use a flashing pan. I cannot stress this enough. I have made a living replacing rot and structural decay directly related to moisture infiltration from leaky thresholds. Just make sure you run a bead of high grade, flexible calking compound toward the warm side under the threshold for a thermal break and to adhere the threshold in place. If the floor isn't level, I like to cut taper strips the width of the rough opening, or shim a 1x6 for the flashing pan to sit onto. Use adhesive to keep everything solid over time.
Tip 3: Decide the Best Position for the Jamb
Once you have the rough opening prepped and jamb temporarily in place with shims, you must decide the best position for the jamb to set into the rough opening, but also adjusted so the door slab will close against the stop touching from top to bottom all at the same time. With double doors, you must ensure that both door slabs line up flush with each other at the bottom. This why I say to myself that I'm adjusting the jamb to the doors.
Tip 4: Use Long, High-Strength Screws
When securing the hinges, use long, high-strength screws. (I like to use a 3 ½" to 4" screw.) Be sure you leave enough play at the top hinge to tighten that screw down the line of time for fine tuning.
Tip 5: Shim the Jamb
One final little nuance: I sometimes shim the jamb in such a way as to flex the non-hinged side ever so slightly wider than the hinge side, because it helps to avoid binding on the edge of the door and jamb with paint build up over time. The whole point to this is mostly being aware to not shim the non-hinge side so tightly that it causes binding.
In any case, this whole article is more about thinking about your craft than about how to install an exterior door. It's about continuous learning and education. It's about putting aside ego and learning from other professionals so you can earn the respect you deserve and the dollars you're worth!
As always, I welcome any tips, tricks, or stories you'd like to share, because I have found no better way to learn than by having a conversation!
