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How to Secure the Door Between Your Garage and House

By Guardian Angel DIY · Updated October 27, 2026 · 9 min read

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The door between your garage and your house is one of the most overlooked entrances in the home. It is usually a plain interior-grade door with a knob lock, it is often left unlocked because it feels like it is inside, and it sits behind a garage door that may be open, forced or opened with a stolen remote. Once someone is in the garage, this door is all that stands between them and your family. The fixes are simple, and most take less than an hour.

Why this door matters

Three things make the garage-to-house door a special risk.

• It is hidden. Once the garage door closes behind someone, nobody on the street can see them working on the interior door. A person can take their time.
• It is often weak. Many are hollow or thin doors fitted with a basic knob and no deadbolt, and short screws hold the frame.
• It is often unlocked. People who lock the front door every night often forget this one, especially when they come and go through the garage.

The garage also contains tools. A crowbar, a hammer and a saw are all within reach for anyone who gets inside, which makes a weak door even weaker. And if your remote is in a car outside, or your keypad code is easy to guess, the garage may open without any force at all. Our guide to securing the garage door and opener covers that outer layer.

Check your door first (10 minutes)

1. The knock test. Rap on the door. A hollow sound means a hollow-core door, which is weak. Solid wood, solid-core, steel and fiberglass doors sound dense.
2. The lock test. Does the door have a deadbolt, or only a knob lock? Is the bolt a full inch?
3. The screw test. Remove one strike plate screw and look at the length. Anything under an inch or so is only holding the thin jamb.
4. The closing test. Open the door halfway and let go. Does it close and latch on its own? Many codes require it.
5. The gap test. Look at the gap at the latch side and under the door. A big gap lets a pry tool in, and lets fumes into your home.
6. The habit test. How often is the door unlocked? Count a week.

The code and safety question

Before you replace this door, you should know why it is built the way it is. A garage can be the place where a fire starts, because it stores fuel, paint and tools. It is also where a running car can fill the space with carbon monoxide. For those reasons, building codes in many places require the door between an attached garage and the living space to be solid or fire-rated, and to close by itself, and they often require sealing gaps.

The rules vary by location and by when the house was built, so check your local code or ask your building department before you replace the door. If you swap it, choose a replacement that meets the same requirements. Do not replace it with a lighter door, and do not remove a self-closing device. Two safety rules apply regardless of code:

• Never run a vehicle in an attached garage, even with the garage door open. Carbon monoxide can seep into the house.
• Install carbon monoxide alarms on every level and near bedrooms, and test them monthly.

Fix 1: Long screws in the strike plate and hinges ($8 to $11)

This is the best value fix on any door. Short factory screws hold the strike plate and hinges to the thin jamb, and a hard push splits it. Replace them with 3 to 3.5 inch screws that reach the framing. It takes about ten minutes.

1. Remove one screw at a time from the strike plate and drill a small pilot hole through the jamb into the stud.
2. Drive in a long screw until snug, without over-tightening.
3. Repeat for the other strike screws, then at least two screws in each hinge on the frame side.
4. Test the latch and the deadbolt. If either binds, back the screws off a little.

Fix 2: A real deadbolt ($25 to $45)

If the door has only a knob lock, add a Grade 1 deadbolt. A deadbolt is a solid bolt that cannot be pushed back, and a Grade 1 rating means it meets the highest residential standard. Use a single-cylinder lock (a key outside, a thumb turn inside), so everyone can leave quickly in a fire. Our deadbolt guide explains the grades and the features to look for.

Fix 3: Reinforce the lock area ($18 to $22)

After the screws, the next weak point is the jamb around the deadbolt. A reinforcement plate spreads the force and stops the frame from splitting. It installs with a drill in about fifteen minutes and releases quickly from the inside, so it does not trap anyone. Do both the screws and the plate: the screws strengthen the connection to the house, and the plate strengthens the jamb itself.

Fix 4: Make the door close and latch on its own

A door that stays open or swings loose defeats the lock. Many garage doors have a spring hinge or a door closer that returns the door to the closed position. If yours does not close firmly, check the closer or spring hinges and adjust or replace them. A door that closes by itself helps with the lock, with fumes and with fire protection. Check that the latch bolt fully engages the strike each time, and that weatherstripping does not stop it.

Fix 5: Seal the gaps

Weatherstripping around the door and a sweep at the bottom help in three ways. They keep out drafts and pests, they reduce the chance that fumes pass into the house, and they make it harder to slide a thin tool through a gap. Check that the weatherstripping does not prevent the door from latching, and replace it when it is worn.

Fix 6: Lock it and use the right habit

• Lock it at night and when you leave. Make it part of the same routine as the front door.
• Keep it locked even when you are home, especially when the garage door is open and you are in the yard.
• Avoid a spare key hidden in the garage. The garage is the first place to look.
• Keep the keypad code private, and change it when anyone leaves your household.

Optional: a backup bar or stop

If you want more delay, a kick-down door stop or a door security bar adds resistance at the base of the door. A kick-down stop is a low-cost extra layer that doubles as a door holder, and a security bar offers much more resistance, but it must release from inside in seconds. Neither should block your escape. Because this door is an exit in a fire, keep any added device quick to release.

What it costs: a simple plan

Common mistakes to avoid

• Leaving it unlocked because it is "inside." It is a main entrance.
• Replacing it with a lighter door. You may break code and weaken protection.
• Removing the self-closer. It matters for fire and fumes.
• Using short screws. The frame is where doors fail.
• Blocking the exit. Any bar or stop must release quickly.
• Running a car in the garage. Never, even with the door open.

If you rent

Ask your landlord before you change a lock or a hinge. A portable door stop, weatherstripping and a carbon monoxide alarm are easy and usually allowed. If the door is hollow, loose or does not close, report it as a repair in writing, since it also affects fire safety.

Frequently asked questions