Installing Exterior French Doors: Install Flashing and Hardware

I’ll start by doing the two side flashings and then the head flashing. One of the details I like to do with a flexible flange like this is to roll the edge of the flashing up on the door by ¼ inch.

It’s only required that we use a 4-inch flashing, but we’re going to use a 6-inch flashing on here. I’m going to roll it up ¼ inch, so I’ll strike a line at 5¾ inches on the wall and line up the edge of the tape here. This way, if the flange ever shifts out of position, I’ll never get an air or water leak in there. Snapping a reference line gives me a consistent overlap in the corner; I wanted ¼ inch, and it’s pretty consistent all the way up.

Now that both sides are flashed, it’s time to do the top. You might think you don’t have to put any flashing on top with this big overhang, but it’s pretty important. Water goes everywhere, especially in a storm, but what if the customer decides to power-wash his house and you haven’t got it flashed? You get water inside the trim or the door. So, the head flashing is important. I call this the “money piece”; you leave this off, the door will leak.

Manufacturers supply Z-flashing for the top of the door. There’s normally a bead of sealant along the bottom of the Z-flashing. Let the flashing squish into the sealant so that no water can push up underneath, and get a good air seal. Come on top of the Z-flashing with another small piece of flashing tape or with the housewrap.

We’re leaving the Z-flashing off for now because we still have to do a lot of trim and siding work; the soffit is a mess. We’ll make sure to put the head flashing on top of the trim.

I need to fill up this area at the top of the door with either another piece of flashing tape or with housewrap. I’ll put up a piece of housewrap right now—a temporary measure until we get the trim in.

Next, I’ll put a bead of caulking along the joint between the flashing and the flange on the sides of the door, for a nice, watertight seal.

I’ll start hardware installation on the passive door—the door that gets closed first and latched. The other one is the active door—the door you need to open first in order to gain access to the house. I’ll start with the escutcheon plates on the passive door; the gasketed one is for the exterior. There are two brass screws that I’ll thread in from the inside. The parts and pieces we’re using here vary from manufacturer to manufacturer; that’s why it’s good to read the instructions before you get started. Be familiar with where the parts go and the sequence in which you need to install them. Don’t be in a hurry. I’m using a regular old screwdriver for this. I’m tempted to use a screw gun because it will be quicker; but with a screw gun, I run the risk of stripping the hardware. This is brass; it’s very soft.

Don’t snug up the screws just yet. Leave the escutcheon plate a little loose until the handle set is in. Grab the interior handle set first. The way to tell which handle set you’re working with is to look at the setscrew; it should be on the bottom. Take a spindle and align the V-groove of the spindle with the setscrew. Use your Allen key to snug up the setscrew into that V-groove. Put the bushing on next, and install the interior handle set from the inside. That’s why I didn’t want to tighten the escutcheon; I need a little bit of wiggle room so that when I put the handle set on, I can get the bushing right in. Next, from the outside, slide the other bushing on and install the exterior handle set. Using the Allen key, tighten the setscrew from underneath the exterior handle set.

Now that the handle is installed, tighten up the screws on the escutcheon plate.

I need to also put the strike on.

On the active door, you have an option on the escutcheon plate: a key lock or a blank. Ours was supplied with a blank, so we’ll have a blank on the outside of the door; there won’t be any key lock on the exterior. Setting up the escutcheon on the active door is the same as on the passive door, except there are a couple of pieces of hardware that aren’t on the other door. Next, install the interior escutcheon plate; the only difference between this one and the escutcheon on the passive door is that this one has a turnbolt on the interior to be able to lock the door.

Just lightly snug up the screws on the escutcheon so that you have wiggle room for when you put the handles in. Here’s a quick tip: When you install the handle set, insert the spindle in the handle and just snug it up with the Allen key in the setscrew before actually installing the handle set in the door. This way, you won’t have to work from underneath. After you snug up the setscrew, just back it off a little bit. Put the bushing on the interior handle set and install the handle from the inside. Then put on the exterior bushing and install the outdoor handle set. Tighten down the setscrews and the screws on the escutcheon plates.

Test the hardware. Everything works perfectly.

Now I can seal up the screw access holes in the door with the plugs provided by the manufacturer.

Before air sealing, I want to install a plate on the bottom, in the sill, to stabilize the double door in case somebody slams it. Only thing is, we put a sill pan in, so we’ll have to breach it in the area of the plate. We’ll just cut out a little piece of the sill pan, put the plate in, and tighten it down. Then put in a bead of sealant along the plate, where you cut out the piece of sill pan.

We’re pretty much done installing the door. The final step is air sealing. I wait until the very end, in case any tweaking or shimming has to be done during installation. To air seal, put backer rod in first. If water should get in behind the door flange for some reason, it’ll hit the backer rod, which has a little channel—so the water will reach the sill pan and then drain out.

To air seal, use spray foam around the perimeter of the door. I like to use a pro gun; when I pull the trigger, I release foam at the end of the nozzle, but the rest of it stays fluid within the nozzle. I’ve accidentally left a can of spray foam attached to the gun for two months, and it still functioned.

Use a window and door foam. It has to have low pressure, low expansion, and closed cell. Closed cell will stop the air movement, and low pressure and low expansion won’t distort the door frame.

The last thing I do on the inside is seal the joint between the sill pan and the threshold. I use sealant to block any air or water from coming through.

Trim off the excess foam, and touch up any spots where the foam didn’t get fully in between the shims.

That’ll be it for the interior. Let’s go outside and put up a couple of screen doors.