How to Install a Door Reinforcement Lock?


A door reinforcement lock is a low-profile lock that might look like much – but can provide an impressive level of extra security to your doorway. These locks use a fairly straightforward design, with a bracket that flips down into a locked position – acting as a physical barricade to anyone trying to force their way inside.

You can install a door reinforcement lock in a variety of different inward opening doors, including both standard single doors and French doors. The basic process of installing them remains the same though, and it should only take about 10 minutes to complete.

I’ll break down how to install a door reinforcement lock in step-by-step detail, so you’ll be able to complete the process on your own in no time at all.

Tools & Materials

How to Install a Door Reinforcement Lock – Guide

Step 1: Plan Installation Location

First off, you’ll want to determine where on your door jamb you plan to install your lock. These locks can be installed either on the side jambs or on the head jamb, depending on your preference.

testing the lock fit
Testing the door lock fit.

You also want to make sure you install the lock at least 6-inches away from any other lock to make it more effective.

With the door closed, and the door lock in the locked position, slide the mounting plate in between the door edge and the jamb. The goal here is to make sure you’ll have enough room for the mounting plate to fit in between without it jamming the door shut.

If the plate doesn’t fit, then you’ll need to break out the hammer and chisel to make a mortise in the jamb. This will allow the mounting plate to fit in place properly without the door being difficult to open and close.

Step 2: Mortise the Door Jamb (Optional)

If your mounting plate didn’t fit, then you’ll need to make room for it by creating a mortise in the door jamb. In my case, the mounting plate actually fit fine, but there was a piece of trim that partially blocked the edge of the lock from sliding all the way into place, so I made a mortise in the piece of trim.

To make the mortise, hold up the reinforcement lock in place where you want to mount it. Then, use a pencil to trace the edge of the mounting plate.

tracing the mortise
Tracing the mortise.

Then using a hammer and chisel remove about 1/16” of material from the door jamb to create the mortise. You don’t need to be perfect here, as the mounting plate will cover up the mortise, so don’t worry too much about it looking pretty.

creating mortise with hammer and chisel
Making the mortise with a hammer and chisel.

When you’ve created your mortise, line up the mounting plate as you did in the previous step, and check the fit. If the door opens and closes smoothly and unencumbered then you’re good to go. If it’s still getting caught, then you’ll need to go back and remove more material until the mounting plate fits in the jamb.

Step 3: Test Fit the Lock

Next up, you’ll want to test fit the lock by partially mounting it in place. In my case, the lock has an oblong-shaped hole for this purpose.

Line up the lock and mark the center of the oblong-shaped hole. Then use your drill bit to create a hole in the same spot you just marked. The oblong hole allows you to make minor adjustments to the position of the lock before you mount all of the remaining crews, so you’ll still be able to fine-tune the fit before reaching the final mounting position.

mounting the door lock

Then partially drive the smaller screw in place to hold the lock in place. You want to fine-tune the fit so the door fits flush with the padded edge of the lock when it’s closed.

Step 4: Fasten the Remaining Screws

Next up, you’ll want to fasten the remaining screws in place to mount the lock in its final position. My lock came with two sets of screws, one ¾” and one 3”. I used the 3” screws to mount the lock in its final position.

fastening the mounting screws

Now, open and close the door a few times and test out your new lock!

One thing to keep in mind with these locks is that they can only be locked/unlocked from the inside. That makes them ideal for weaker and more vulnerable doorways like French doors.


Denis Gardner

I've loved tinkering and fixing things for as long as I can remember. So, naturally, I gravitated towards DIY and home improvement when I bought my first home. Nowadays you can find me writing about my passions or messing around with my newest tool!

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