How to Install a Dog Door in a Metal Door (Step by Step)

Yes, you can put a dog door in most metal doors. Here is how to install a dog door in a metal door: confirm the door is not fire-rated, mark a square, level opening at least 4 inches from the bottom and side, drill the corners, cut with a fine-tooth metal blade, prime the bare edges, then sleeve a self-framing pet door through and screw it together.

The specifics below come from Hale's Door Model installation manual, which has a section for metal and steel-skin doors.

Can you put a dog door in a metal door?

In most homes, yes. With the right blade, a steel door cuts cleanly. Hale's manual puts it plainly: "The Hale Pet Door™ door model is completely self-framing. There is no need to frame out the inside of your door."

Before you mark anything, check these four things.

Fire-rated doors and the garage-to-house door

Do not cut a fire-rated door on your own. Fire doors carry a label that identifies the agency that certified them. The Steel Door Institute explains that changes beyond what the NFPA 80 standard allows require contacting that listing agency with a description of the change, and warns that "even small modifications" can let fire and smoke spread faster (Steel Door Institute).

Be careful with the door between an attached garage and the house, too. The International Residential Code, Section R302.5.1, requires that door to be solid wood or solid or honeycomb-core steel at least 1 3/8 inches thick, or a 20-minute fire-rated door, with a self-closing or automatic-closing device (City of Boise IRC handout). A hole in that door can work against the purpose of the rule. Ask your local building department before you cut it.

Your door's warranty

Cutting an opening may affect the warranty from your door's manufacturer. Check the door warranty before you start.

Steel-skin foam core vs. hollow metal

Metal doors come in two broad kinds. Steel-skin doors are what Hale's manual describes as "a foam core covered with thin steel skin." They cut much like any other door, but the thin skin dents easily, so blade choice and saw control matter.

Commercial-style hollow metal doors are different. They can have welded internal reinforcements such as stiffeners, which the Steel Door Institute notes can sometimes show through paint (SDI primer and topcoat guide). You do not want to discover one halfway through a cut. If the door is a commercial-style hollow metal door, talk to an installer before cutting.

Door thickness: 1 1/4" to 2" for the Door Model

Measure the door's thickness at the spot you plan to cut. The Hale Door Model pet door is designed for doors between 1 1/4" and 2" thick. The spec sheet lists the standard gap between the frames as 1 9/32" to 2", and the frame can be factory modified to collapse to as little as 3/4". If your door is between 1/2" and 1 3/8" thick and you did not order a factory cut-down, the kit should include a build-out that matches the frame color.

Sizing and placement

Pick the size before you pick the spot. Hale's manual says, "If in doubt, larger is better." Use the pet door sizing guide to measure your dog:

• Height: measure from the floor to the top of the shoulders (withers). The top of the flap should be 1 to 2 inches above that.
• Width: measure the widest point of the chest and add 1 to 2 inches.
• More than one pet: make sure the tallest pet has shoulder clearance and the shortest one will not have to jump.

Then check the placement rules from the manual:

• Keep the rough opening at least 4 inches from both the bottom and the side of the door "to maintain the integrity of the door construction." The manual notes this can vary with the size and type of door.
• Make sure nothing above the opening, such as a lockset, kick plate or closer, blocks the security cover from sliding in. If something does, a side-loading cover is available.
• Keep the opening square and level on both faces of the door.

Common rough openings from the sizing guide (width x height):

If you ordered a custom size, use the rough opening dimensions you gave Hale when you ordered.

Tools and blades by door type

You need a drill to start the opening and the screw holes, a saw to finish the cut, and a screwdriver. Add a level, a pencil, painter's tape, a tape measure, drop cloths, a metal file, eye protection and gloves. The kit includes the 5/8" #6 Phillips screws and a 7/64" drill bit.

The right saw depends on what the door is made of. This table summarizes Hale's manual:

The two blade counts are not a contradiction. The 14-tpi blade is the manual's general metal-door instruction; the 18-tpi minimum is its specific advice for the thin skin of a foam-core door when the opening is larger than a Medium.

How to install a dog door in a metal door, step by step

If you get stuck, Hale offers a free consultation with an experienced installer at 1-800-646-4773.

1. Check the kit. Confirm you have both frame halves, the security cover, the screws, the 7/64" bit and the instructions, plus the build-out if your door is thin.
2. Protect the area. Lay drop cloths on both sides of the door.
3. Mark the opening. Use a level and pencil to mark all four sides of the rough opening. Outline it with masking tape and step back to check size and height one last time.
4. Drill the corners. Drill holes at the corners, inside your lines, large enough for the saw blade. The manual suggests holding a level on the drill bit so the inside and outside faces of the opening stay aligned.
5. Cut the opening. Use the blade from the table for your door. Let the saw do the work. The manual warns: "Be careful that the saw blade does not dent the other side of the door while you cut."
6. Clean the edges. Deburr and prime the cut metal (see the next section) before the frame goes in.
7. Prep the frame. Separate the frame halves, remove the security cover, and back out the pin-lock screws a few turns so they do not hold the frame off the door.
8. Test fit. Put the inner frame (the one with the cover track) in from inside, slide the outer frame in from outside, and squeeze the halves together. If you use the optional raincap, hook it on the top of the outer frame first.
9. Drill and screw. Using the pre-drilled pilot holes and the supplied bit, drill one hole at the bottom and insert one screw loosely. Level the frame, tighten, then drill and drive the rest. Retighten the pin-lock screws.
10. Seal. Caulk three sides as described below.
11. Finish. Slide in the security cover, test the lock, and clean the frame and flaps with soap and water or an ammonia-free glass cleaner. Adjust the magnets if the flaps do not seal and swing freely.

Deburring and protecting the cut edges

Cutting a steel door leaves sharp burrs and exposes bare steel along the edge of the opening. Run a metal file along each edge to knock off the burrs. That lets the frame seat flat.

Then treat the bare metal. For scratches that reach bare steel on a steel door, the Steel Door Institute recommends sanding to bare metal with 300-grit sandpaper, wiping it clean, and touching up with a rust-inhibitive primer. If rust has already formed, it says to sand it off and re-prime with a direct-to-metal (DTM) primer with rust inhibitors (SDI). Apply the same approach to the cut edges and let the primer dry before you install the frame. The pet door frame covers the edge, but moisture can still reach it.

Sealing and caulking: three sides, not the bottom

Hale's manual says you can fill gaps or seal the edges with caulk once the pet door is installed, with one firm rule: "Do not caulk the bottom of the inside or outside frame."

• Put blue painter's tape around the three sides you will caulk.
• Apply caulk to the top and both sides, smooth it, then pull the tape for a clean line.
• For the best protection against water and better energy efficiency, the manual recommends caulking both the inside and outside frames.
• On embossed or panel-style steel doors, fill deep gaps with caulking backer rod first, then caulk.

On a door that faces rain, consider a raincap, which hooks onto the outer frame and diverts water from above.

Common mistakes

• Cutting a fire-rated or garage-entry door without checking. Look for a label and ask first.
• Using a coarse blade on a thin steel skin. For openings larger than a Medium in a foam-core door, the manual calls for at least 18 teeth per inch.
• Denting the far side. A long blade or too much force can push into the opposite skin.
• Going too low or too close to the edge. Stay at least 4 inches from the bottom and side unless the door type allows otherwise.
• Buying too small. The manual notes a door that is too small may be harmful for your pet.
• Skipping the test fit. Fit the frames before you drill any screw holes.
• Leaving bare steel unprimed. Prime the edges before the frame goes on.
• Caulking the bottom. Leave the bottom of both frames uncaulked.

When to hire a pro

Any person with a working knowledge of power tools and basic home construction can install a Hale Door Model, according to the manual. Hire help if the door may be fire-rated, if it is a commercial hollow metal door, if the door is expensive or new, or if you are not comfortable cutting steel. You can find an installer near you, or call 1-800-646-4773 for a free consultation. For a broader look at the tradeoffs, see DIY vs. professional dog door installation.

Whoever installs it, the Door Model carries a lifetime frame warranty and 10-year prorated flap warranty. Full dimensions for every size are on the technical specs page.

Frequently asked questions

Can you put a dog door in a steel door?

Yes. Steel-skin doors have a thin steel skin over a foam core and can be cut with a diamond blade and a fine reciprocating saw blade. A self-framing pet door needs no framing inside the door. Do not cut a fire-rated door, and check local code before cutting the door between your garage and house.

What blade cuts a metal door for a dog door?

Hale's manual calls for a 14-tooth-per-inch reciprocating saw blade for metal doors. For steel-skin foam-core doors, use a diamond blade on a circular saw for Medium and smaller openings, or plunge the diamond blade on each side and finish with a fine blade of at least 18 teeth per inch.

Do I need to frame the inside of a metal door?

Not with a self-framing pet door. The Hale Door Model has an inner and outer aluminum frame that sleeve together through the opening and screw tight, covering the cut edges. You do not need to add wood framing inside a foam-core or hollow door. Do prime any bare steel along the cut edges first.

How far from the bottom of the door should a dog door be?

Hale's installation manual says the rough opening should be no less than four inches from both the bottom and the side of the door to maintain the door's structure. This can vary with the door's size and type. Set the height so the top of the flap sits 1 to 2 inches above your dog's shoulders.

Will a dog door in a metal door rust?

Cutting exposes bare steel, which can rust if left untreated. File off the burrs, then follow the Steel Door Institute's guidance: sand bare spots, wipe them clean and apply a rust-inhibitive primer. Caulk the top and sides of the pet door frame, but leave the bottom uncaulked.

Sources

• Hale Pet Door, Door Model Installation Instructions (PDF): www.halepetdoor.com/diy-installation-manuals/Door_Model_Installation.pdf
• Hale Pet Door, Door Model Technical Specifications (PDF): www.halepetdoor.com/specs/doormodeltechnicalspecifications.pdf
• Steel Door Institute, "Common Field Issues Affecting Fire Doors & Frames"
• Steel Door Institute, "Proper Jobsite Storage of Steel Doors & Frames and Field Application of Primer and Topcoat" (PDF)
• City of Boise Planning and Development Services, IRC Code Handout #435, Section R302 Dwelling/Garage Separation (PDF)