Start with the door, not the box
It is natural to begin a lock project in the hardware aisle, comparing finishes and prices. A better starting point is the door itself. A lock is a guest in the door, and the host sets the terms. If the door is warped, the frame is soft or the measurements do not match, the most carefully chosen lock will disappoint.
Spending twenty minutes on the door first has a few benefits. You learn exactly which lock sizes fit. You spot problems that would have wrecked a new installation. And you can decide whether the project is a simple swap, a swap plus a repair, or a job for someone with the right tools.
This guide walks through the checks in a sensible order. None of them need special equipment beyond a tape measure, a notepad and a little patience. Photographs of the door and frame, taken from a few angles, are a useful record and can help if you later call for advice.
Keep a flashlight handy for this job. Many of the problems show up in shadows: a hairline crack near the strike, a missing screw in a hinge, a gap in the frame where the latch should seat.
Think of the checks as a form of insurance for your purchase. A few minutes of looking and measuring protects the money you are about to spend and the time you will invest in installation.
Measure what the lock needs to fit
Locks are made to fit standard dimensions, so the numbers matter. Start with the thickness of the door, measured at the edge. Most residential entry doors fall within a common range, but older, thinner or custom doors can differ. A lock designed for one thickness may not work on another without an adjustment kit.
Next, measure the backset, which is the distance from the edge of the door to the center of the large hole drilled in the face. Common backsets exist, and many locks come adjustable, but you should verify. Then measure the diameter of the large hole and the smaller hole in the edge. Our guide on backset and door prep measurements shows where to place the tape.
Also note the handing of the door, meaning which way it swings, and whether the lock you want is reversible. Some are, and some are made for one side only. Finally, see whether the door has any existing cutouts for a deadbolt, a second lock or a peephole, and whether they line up.
Do the measuring twice. A reading that is off by a small amount can lead you to buy the wrong part, and returns are a hassle. Write numbers down as you go instead of trusting memory.
Bring a straight edge or a small level if you have one. Holding it against the door face and frame can show warping that the eye misses. A door that bows even slightly can pull the bolt out of line when the lock is engaged, and the cure is usually at the hinges or the door itself, not the lock.
- Door thickness, measured at the edge.
- Backset, from the door edge to the center of the large hole.
- Diameter of the large face hole and the smaller edge hole.
- Handing of the door and whether the lock is reversible.
- Any extra holes for deadbolts, peepholes or old hardware.
Tell the dispatcher the Orlando area, what happened and what you are standing in front of, whether a door, a vehicle or a gate.
CallCheck how the door hangs and closes
Stand outside and close the door slowly. Watch the gap between the door and the frame along the top, the sides and the latch edge. It should be roughly even all around. A gap that is wide at the top and narrow at the bottom, or one that pinches at a corner, suggests the door has dropped or the hinges have loosened.
Listen to the latch as the door closes. It should click cleanly without slamming and without needing a push. If you have to lift or press the door to latch it, the bolt and strike are out of alignment. A new lock will not cure that, and it may make it worse if it demands tighter tolerances. Our guide on when a door will not latch explains common causes.
Look at the hinges. Are the screws tight and the leaves flush with the wood? A loose hinge shifts the door and throws the lock off. Tighten what you can, and note any screws that spin without gripping, which mean the wood behind them is stripped.
If the door has a sweep or weatherstripping, check whether it drags. Rubbing on the threshold can mimic a lock problem. Adjust or replace the sweep if needed before blaming the hardware.
Try this test with the lock open: close the door gently and see whether the latch tongue lands in the middle of the strike opening. If it rides on one edge, mark which side. That small observation tells a locksmith, or you, whether the plate needs shifting or the door needs adjusting at the hinges.
Look at the frame and the wood around the lock
Press a thumb gently into the frame around the strike plate and the latch hole. The wood should feel solid. If it feels soft, spongy or crumbles, there may be rot or insect damage. Tap with a knuckle along the frame, and listen for a hollow sound in places where it should be solid. Soft spots call for repair before any new hardware goes in.
Look for cracks and splits near the strike, especially above and below it. A hairline crack can grow under stress. Check the area around the hinges as well. Past attempts to force the door, or just years of slamming, can leave damage that is not obvious from a distance. If you see any, take photos and mention them when you talk to a locksmith.
Humidity matters here. In Central Florida's wet season, doors and frames can swell, sometimes enough to change how a lock fits. If a door sticks in summer and loosens in winter, note it. A lock should be set to work across the seasons, not only on the day it is installed. See humidity and swollen doors.
Consider the finish and the climate when you look at the hardware. Rust staining around the strike or hinges suggests moisture is getting in. That is a clue to choose corrosion resistant parts and to seal the area when you finish.
Check the strike plate and the screws
Inspect the strike plate on the frame. Is it flush with the wood? Does the bolt hit the center of the hole? Are the screws tight, and do they look long enough? Builders often use short screws that only reach the thin jamb. Longer ones that reach the stud behind are a common, inexpensive improvement. Our guides on how strike plates affect door security and screw length and strike plate security explain why.
If you plan to install a better deadbolt, check that the strike is up to the task. A heavy bolt in a flimsy plate is a mismatch. Ask whether a reinforced plate would suit your frame. You may find that spending a little on the plate and screws improves the door more than spending a lot on the lock itself.
Make a note of the shape and size of the existing plate. If you replace it, the new one should match or you may have to alter the frame. Cutting more wood out of the frame weakens it, so it is better to choose a plate that fits what is already there.
Think about lighting and visibility at the door. A well lit entry discourages trouble and makes it easier to use the lock at night. See peepholes, door viewers and cameras at the entry for related ideas.
Door color and finish can also hide problems. Layers of paint thicken the edges of a door, narrowing gaps and making the latch tighter in the wet season. If a repaint is planned, consider doing it before the new lock goes in, so the final fit includes the paint.
Glass, sidelights and nearby weak points
Look at what is around the lock. A door with glass close to the thumb turn, a sidelight next to the frame or a window within reach of the handle changes the security picture. A strong lock does not protect against someone reaching through broken glass to turn a knob. Options exist, including moving the lock, reinforcing the glass or choosing a different style. We discuss them in single cylinder or double cylinder deadbolt.
Check the hinge side as well. If the hinges are exposed on the outside, or the door opens outward, think about whether the pins and hinge screws are secure. See hinge side security basics for what to look for.
Look at the door material itself. A hollow core interior door is not made for exterior security. A thin wood door with a decorative panel may be weak around the lock. Metal and solid wood or fiberglass doors with proper cores perform better. If the door is the weak point, consider whether upgrading the door makes more sense than upgrading the lock.
If you rent, remember that changes to the door or lock may need permission. Ask first, keep original parts and report frame damage to the landlord instead of repairing it yourself without approval.
Match the lock to how the door is used
Consider who uses the door and how often. A front entry that sees heavy daily use needs a lock built for it. A side door used rarely can be more modest. A door used by children needs a handle they can operate. A door used by an older relative may call for a lever. See choosing between knob, lever and handleset locks for a comparison.
Think about grade and construction too. A higher grade lock is built to take more use and force, but only helps if the door and frame support it. Our overview of lock grades explained for homeowners helps you read the labels.
If you want a smart or keypad lock, check the clearance on the inside of the door for the bulkier housing, and think about batteries and weather. Our note on smart lock questions to ask first lists the points to settle before buying.
Special cases: old homes, metal doors and new construction
Older homes may have mortise locks, unusual door thicknesses or frames that have been painted and patched many times. A modern lock may require adapting the door or choosing a model designed to fit older prep. Our pages on mortise locks in older homes and skeleton keys in historic homes explain what you may be dealing with.
Metal doors have their own prep, and drilling them requires care. A metal door in a wooden frame needs attention to the strike side so that the plate does not tear out. In new construction, you have the advantage of planning from the start. See entry doors in new construction, hardware planning.
For remodels, doors may be replaced, reframed or rehung. A new door can have a different prep from the old one. Check before you buy locks, and ask the supplier about hole sizes. Matching locks to a new door at the planning stage saves rework later. Our guide on renovation lock planning for remodels covers it.
Add a note about any paperwork or rules that apply, such as an HOA requirement on exterior finishes or a landlord condition on changes. Requirements vary, so the person to ask is your association or property manager.
A worked example: replacing a front door deadbolt
Suppose a household wants a stronger deadbolt on the front door. They begin by measuring: the door is a standard thickness, the backset is a common size, and the holes match what most deadbolts expect. So far, so good. They close the door and notice that the latch edge gap is wider at the top than at the bottom, and the bolt drags slightly when turned.
Looking closer, they find that the top hinge has two loose screws. Tightening them reduces the gap but does not remove it. The strike plate is held by two short screws, and the wood around one of them feels slightly soft. The household realizes that the lock was never the whole story. They decide to replace the hinge screws with longer ones, repair the soft spot and fit a reinforced strike, then install the new deadbolt.
The result is a lock that turns smoothly, a door that closes evenly and a frame that holds the bolt properly. Had they simply bought a stronger lock, they would have spent more and gained little. The checks cost them an afternoon, and they changed the outcome. This kind of sequence is common, and a locksmith can walk through it with you if you prefer to have help.
Write it down: a short door profile
Once you have done the checks, write a short profile for each door. Include the thickness, backset, hole sizes, handing, frame condition, strike plate type, any problems and what you want from the new lock. Keep it with your records. It makes shopping simpler and helps if you later ask for help.
A profile also helps you compare options honestly. If a lock does not match your numbers, you know before you buy. If the frame needs repair, you know before the lock arrives. If a door has quirks, you can describe them accurately instead of from memory.
When you call a locksmith, the profile lets you describe the situation clearly. The more precise the description, the better the advice. Ownership or authority is confirmed before work starts, the work and price are explained first, and the finished lock is tested with you.
When to bring in a locksmith
If the checks reveal problems you are not comfortable fixing, such as a soft frame, a binding door or an odd prep, a locksmith can help. Describe what you found, and they can explain what is likely needed. For lock replacement and repair, see lock replacement and repair, and for a full look at your doors, see need locks looked over.
You can also ask whether a rekey might serve you better than a replacement. Our guide on lock replacement or rekeying explains how to decide. Often the lock is fine and what you want is a new key.
A little preparation makes the whole project calmer. Check the door, write it down, choose a lock to match and get help where you need it. The result is a lock that fits, works smoothly and does its job.
Questions people ask
What measurements do I need before buying a lock?
Door thickness, backset, the diameter of the large face hole and the smaller edge hole, and the handing of the door. Note any extra holes for old hardware. These numbers help you pick a lock that fits without altering the door.
How can I tell if my frame is damaged?
Press gently around the strike plate and latch hole, looking for soft or spongy wood, cracks or splits. Tap along the frame to listen for hollow spots. Screws that spin without gripping are another sign. If you find damage, have it repaired before new hardware goes in.
Why does my door stick in summer?
Wood absorbs moisture and swells in humid weather, which can make the door bind against the frame or the bolt press against the strike. It may ease in drier months. Checking hinges and fit helps, and a professional can advise on lasting fixes.
Should I replace the door or just the lock?
If the door is thin, hollow, damaged or poorly fitted, a better lock may not help much. A solid door in good shape with a sound frame deserves a good lock. A locksmith can look at both and give an honest view.
Do I need to check the strike plate if I only want a new handle?
It is a good idea. A new handle may change how the latch sits, and a worn or misaligned plate can make the door hard to close. A short look and a tightening of screws costs almost nothing and can prevent trouble.
Can a locksmith help me choose a lock that fits?
Yes. Describe your door, the measurements you took and what you want. They can recommend hardware that suits the prep and the frame, and explain the work and price before anything begins.