How to Reinforce Doors: Entry Door and Lock Reinforcements

Updated: Jan. 03, 2024

Three simple upgrades to improve door security

FH04SEP_ENTDOR_04-2 door security secure doorsFamily Handyman
Prevent break-ins by upgrading and strengthening your deadbolt and lockset. Learn how to install a Grade 1 deadbolt, how to install a four-screw strike plate box, and how to beef up the lockset strike plate to protect your home.

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A full day

Step 1: Overview of door security locks

I never realized how easy it is to kick in a solid door that has old hardware until I tried it on our demonstration door. With two kicks in only five seconds, I destroyed the doorjamb and was in the house.

You need to upgrade the deadbolt and lockset plates of your exterior doors if you haven’t already done so. FBI burglary statistics show that 65 percent of home break-ins occur by forcing in the front, back or garage service door (not to mention the 12 percent of entries where burglars find your “hidden” key or simply walk in through an unlocked door). Here are some ways to prevent garage break-ins.  

In this story, we’ll show you how to strengthen your exterior secure doors in three ways. We’ll replace an old deadbolt with a quality Grade 1 deadbolt. Then, we’ll replace the deadbolt door strike plate with a four-screw strike box and faceplate—attached with 3-in. wood screws that reach the wall frame. Finally, we’ll replace the lip door strike plate and its wimpy 3/4-in. screws with 3-in. wood screws. We’ll also show you a handy method to turn a small deadbolt hole into a larger hole.

The techniques we show in this article will work on any type of exterior door. But keep in mind that these techniques may not be as effective if you have glass sidelight windows or large glass panels in your doors.

For this project, you need only basic carpentry tools, as well as a 2-1/8 in. hole saw bit and a 1-in. spade bit (check the deadbolt packaging for the exact bit size required). Home centers usually carry deadbolt installation kits with the right size bits. Sleep soundly at night knowing your home is safe from intruders with these apartment door security products.

Step 2: Check all exterior doors

A secure entry starts with a solid door and a Grade 1 or Grade 2 deadbolt with a solid 1-in. long throw bolt (see “Buying a Deadbolt”). Any exterior door that only has a lock in the doorknob isn’t secure. A sturdy screwdriver or small pry bar can quickly bow the doorjamb enough to release the latch.

Check your existing deadbolt. First, make sure the screws are tight. Open the door and extend the throw bolt. If it extends less than 1 in., or if it’s wobbly, a new deadbolt will be more secure.

Next, check the doorjamb and both strike plates. Remove the screws from the deadbolt and lockset strike plates on the door frame. If the screws aren’t 3 in. long, replace them, and also upgrade both plates. (Note: Use shorter screws if sidelight windows are less than 3 in. from the doorjamb.) These longer screws will reinforce the doorjamb, which is a vulnerable spot.

Step 3: Replace the deadbolt

Photo 1: How to remove an old deadbolt lock

Unscrew and remove the old deadbolt. Measure the hole size and backset distance before buying a new deadbolt.

Photo 2: Rebore the hole (if necessary)

Clamp 1/4-in. plywood over the hole location. Mark the new, larger hole centered over the existing hole, then bore it with a hole saw.

Photo 3: How to install a new deadbolt

Screw in the new deadbolt, chiseling out additional wood if necessary to get a flush fit. Then insert and screw in the new cylinder.

How to Replace a Deadbolt

Begin by removing the old deadbolt. Almost all types are held by two screws on the interior side of the door and two screws on the faceplate (Photo 1). Measure the cylinder hole size and the “backset” distance, that is, the distance from the center of the hole to the door edge (Photo 1). You’ll need these dimensions when you purchase a new deadbolt.

Photo 2 shows how to enlarge a deadbolt hole using scrap lumber, a task that is only necessary if your new deadbolt is too big to fit the existing hole (the normal size for a cylinder hole is 2-1/8 in.). The scrap board engages the center guide bit of the hole saw and keeps the new hole centered. Otherwise, you can’t get a clean and accurate cut.

To find the starting point for the hole saw bit, clamp the scrap board to the door and mark both the vertical and the horizontal center of the new cylinder hole. Make sure to hold the drill level and straight so the hole saw bit doesn’t bind and jerk your wrist and arm. If you don’t have a full-depth hole saw bit, chip the wood away from a partially drilled hole, then continue drilling. Go slow so you don’t splinter the opposite side when the bit goes through the door.

Now clean up the hole and test-fit the deadbolt. If the throw-bolt hole (which runs from the cylinder hole to the door edge) is too small, clean it out with a file. Make sure the attached throw-bolt door strike plate fits flush (Photo 3), then attach the bolt followed by the deadbolt cylinder. Hand-drive the screws; a power drill may strip the threads.

Odds of Home Burglary*

Your house is at greater risk of burglary if:

  • It sits on a corner lot (more visible to a browsing burglar and a natural place to stop and ask for directions)
  • It is located close to a major highway exit (less than 1 mile)
  • It is located on a through street, which gives a burglar a quicker escape (dead-end streets and cul-de-sacs are safer)
  • It borders a wooded area or playground (provides concealed access for burglars)
  • It is in a wealthier neighborhood
  • It features no signs of young children living there (burglars avoid as someone may be home)
  • It was recently purchased (burglars know you haven’t yet developed close familiarity with neighbors).

Effective burglary deterrents:*

  • Burglar alarm installed
  • Deadbolt locks on all secure doors
  • House is occupied
  • Newspaper and mail picked up
  • Lights and noise (TV, radio) inside house (set on timer when gone)
  • Car in the driveway
  • Motion-activated exterior lights
  • Dog in the house.

(*Taken from a research study, “Knowing Your Odds: Home Burglary and the Odds Ratio,” by S. Hakim, G. Renger and Y. Shachamurove, City College of New York and University of Pennsylvania, Sept. 2000)

Step 4: Replace the lockset door strike plate

Replace the lockset strike plate

Remove the lockset’s lip strike plate and 3/4-in. screws. Predrill and attach a new plate with No. 8 x 3-in. screws that are angled in slightly to catch the stud. Predrill with a 1/8-in. bit.

To further reinforce the doorjamb, install a new strike plate in place of the old lip door strike plate that serves the doorknob lockset. Attach it with 3-in. screws. Make sure the screwheads seat flush with the face of the strike plate. We used No. 8 x 3-in. screws. No. 10 x 3-in. screws (used for the deadbolt plate) were too large. Remember to angle the screws back slightly to be sure to catch the framing (Figure A). Again, you may have to chisel a slightly larger mortise and predrill to drive the screws.

Buying a Deadbolt

Most people choose a deadbolt for its color or finish, but when entry door security locks are paramount, the critical deadbolt feature is its grade. The American National Standards Institute (ANSI) subjects all locks and components to attacks by hammers, saws, wrenches and other tools. Then it grades the lock: Grade 1 (best and toughest), Grade 2 or Grade 3.

Most locks you find in home centers and hardware stores are Grade 2 or 3. Some Grade 2 locks may list Grade 1 components on the package, but that doesn’t give the lock a Grade 1 rating. However, Grade 2 is still a good-quality lock for residential use. We only found one fully compliant Grade 1 deadbolt in local home centers and hardware stores. Professional locksmiths also are a good resource to find Grade 1 deadbolts.

Before you shop for a deadbolt, measure the hole size where the current cylinder fits, as well as the “backset” distance from the center of the cylinder hole to the edge of the door (Photo 1, Step 3). Most new deadbolts require a 2-1/8 in. cylinder hole, but some of them have inserts to fit the smaller 1-1/2 in. hole, so you don’t have to drill to enlarge the hole (Photo 2, Step 3).

The backset distance is usually either 2-3/8 or 2-3/4 in., so make sure the new deadbolt has the identical backset. Most new locks are adjustable to fit either backset dimension. Just read the box carefully (you may have to open it and read the directions to find the information).

Also decide whether to buy a single cylinder (keyed on exterior side of lock only) or a double cylinder deadbolt (keyed on both sides). Check local building codes too, as they may prohibit double cylinder locks for fire safety reasons (it’s more difficult to escape because you must have the key).

Step 5: Replace the deadbolt strike plate

Photo 1: Mark the deadbolt hole

Mark the center of the existing deadbolt hole. Then remove the old strike plate.

Photo 2: Score the outline of the new strike plate

Align new strike faceplate on the jamb, predrill screw holes and attach it. Score around the inner and outer edges with a utility knife. Remove the faceplate.

Photo 3: Drill out the strike box

Drill two holes that span the strike box dimensions, using a 1-in. spade bit.

Photo 4: Chisel the jamb

Chisel out the strike box and strike plate areas so the strike plate will fit flush with the doorjamb surface.

Photo 5: Install the strike box and plate

Drill pilot holes for all four No. 10 x 3-in. wood screws. Install the top and bottom screws.

Photo 6: Finish up

Drive the final two screws so they’re flush inside the box.

Install a heavy-duty door strike plate lock to strengthen the doorjamb. We didn’t use the strike plate lock that came with the deadbolt. We opted for a more secure strike box plate that features four screws instead of two. (Two screws are installed inside the strike box to add strength; see Photo 6.) Mark the center of the old deadbolt strike plate (Photo 1), then temporarily install the new faceplate and deeply score around it to mark its position (Photo 2).

Next, remove the plate, then chisel and drill out space for both the new plate and the strike box. If the strike box is larger than the existing hole, use a 1-in. spade bit to bore two holes, spaced apart the width and the depth of the box (Photo 3).

Now, remove the wood with a wood chisel to fit both the strike box plate and the faceplate (Photo 4). Be sure to use the wood chisel with the bevel side against the wood to keep from gouging too deep.

Finally, mount the plate and box and attach them with four 3-in. screws (Photo 5). Predrill pilot holes into the wall studs to make the screws easier to drive. Set the screws snug to the plate; overdriving might bow the jamb.

Now, kick back and rest a little easier, knowing you’ve made your home more secure.

Figure A: Doorjamb Cutaway

Three-inch screws will go through the frame and penetrate the wall studs 1-1/2 to 2 in. Angle the screws back slightly into the wall to make sure they hit the studs. The studs become the primary door reinforcement, not the jamb.

Required Tools for this door reinforcement Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Cordless drill
  • Utility knife
  • Wood chisel
You’ll need this specific bits for your drill:
2 1/8 in. hole saw,
1 In. spade bit

Required Materials for this door reinforcement Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

  • 3-in. screws
  • Grade 1 or 2 deadbolt lock (1 in. long throw bolt)
  • Lockset strike plate
  • Reinforced deadbolt strike plate