What does deadbolt installation actually involve?
A deadbolt is the part of your entry door that does the real work against force. The latch in a knob or handle keeps the door closed on a normal day. The deadbolt keeps it closed when someone leans on it, pries at it, or kicks it. That only works if the bolt is the right size, the holes are cut cleanly, and the bolt lands in a strike plate that is screwed into the framing behind the jamb rather than just into the thin wood of the jamb itself. Most of what we do on a deadbolt installation call comes down to those details, not the lock body.
People in Monrovia call us about deadbolts for a handful of reasons: a front door that never had one, an old one that sticks or spins freely, a move into a new house or apartment, a break-in attempt that left the door or jamb damaged, or a decision to switch to a double cylinder because there is glass next to the door. Each of those leads to a slightly different job, so we begin by looking at the door, the edge, the jamb and whatever hardware is already there.
Single-cylinder or double-cylinder: which deadbolt fits your Monrovia door?
A single-cylinder deadbolt takes a key on the outside and has a thumbturn on the inside. It is the standard choice for most homes because anyone inside can leave quickly without hunting for a key. If your door is solid and there is no glass within arm's reach of the interior hardware, this is almost always what we recommend.
A double-cylinder deadbolt takes a key on both sides. Its purpose is narrow: if there is a window, a sidelight or a glass panel in the door close enough that someone could break it, reach in and turn a thumbturn, a keyed interior cylinder removes that shortcut. The trade-off is real. In a fire or other emergency, anyone inside needs a key to get out, and a key that is lost, misplaced or too far away becomes a hazard. Some situations, including rental agreements and certain occupancies, restrict or discourage double-cylinder locks, so we talk through your setup honestly before installing one and tell you plainly when a single cylinder is the better answer.
- Single cylinder: simplest exit, best for solid doors with no nearby glass.
- Double cylinder: for doors with glass or sidelights within reach, with a key needed from inside.
- Grade matters: deadbolts are rated under the ANSI/BHMA system, with Grade 1 the heaviest-duty and Grade 3 the lightest residential rating.
- Finish and style are cosmetic, but the bolt, the strike and the way it is installed decide how well the door resists force.
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Call (213) 577-1366How we install or replace a deadbolt, step by step
Whether we are adding a new deadbolt or replacing a worn one, the order of work is the same. We do not rush the measuring, because a deadbolt that is a fraction off will bind, and a deadbolt that binds eventually gets left unlocked.
- Inspect the door: thickness, material, condition of the edge, the jamb, and any glass nearby. This tells us whether a standard install is enough or whether the door needs repair first.
- Choose the lock with you: single or double cylinder, hardware grade, finish, and whether it should be keyed to match your existing locks or work with a key you already carry.
- Check the prep. Most residential doors use a face hole of 2-1/8 inches and an edge hole of 1 inch, with a backset of either 2-3/8 or 2-3/4 inches. If we are replacing a deadbolt, we confirm which one your door has. If it is a new install, we mark and drill with a jig so the holes are square and centered.
- Cut the latch recess on the edge of the door so the faceplate sits flush, then set the bolt assembly and cylinder and tighten the through-screws evenly.
- Install the strike plate and reinforce it with long screws that reach the wall framing, so a kick does not simply split the jamb.
- Test the lock: bolt fully extended, no drag on the strike, smooth key action from each side, and a clean thumbturn or second key cylinder. We run it with the door closed and open, not just on the bench.
- Hand over the keys, explain how the lock is set up, and leave the door and floor clean.
What affects the cost of deadbolt installation?
We do not give a number over a web page, because the honest answer depends on the door in front of us. What we can do is explain what moves the total up or down, so nothing on the invoice is a surprise. We walk through these factors before we start work.
The lighter-cost route is usually a straightforward replacement on a door that already has the right holes in good condition. Adding a deadbolt where none existed, or repairing a door that has been poorly drilled before, takes more labor and sometimes extra hardware.
- New install versus replacement: drilling new holes takes more work than swapping a deadbolt into existing ones.
- Single versus double cylinder, since the double has an extra keyed cylinder and more parts.
- Hardware grade: heavier-duty deadbolts cost more than light residential ones.
- Condition of the door and jamb: oversized or misaligned holes may need repair plates or filler, and a split jamb may need reinforcing.
- Strike and jamb reinforcement, which is worth doing on any entry door but adds material and time.
- Keying: matching an existing key, keying several locks alike, or adding spare keys.
- How many doors are involved in one visit.
- Timing and travel: a late-night call is different from a scheduled daytime appointment, and we drive to Monrovia from our Westwood base.
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Call (213) 577-1366Deadbolt replacement, rekey, or something else?
Not every deadbolt problem needs a new deadbolt. If the lock works smoothly and you only want different keys, for instance after a move or after a key went missing, rekeying is often the more economical route, because we change the internal pins and keep the hardware. If the lock is worn, loose, damaged, or simply too light for the door, replacement is the right call.
We would rather tell you which one you need than sell the larger job. If the bolt is fine but the door has dropped or swollen so the bolt scrapes the strike, a small adjustment or lock repair may be all it takes. If you want a keypad or app-controlled lock instead of a traditional key cylinder, that is a different product and a different install, and we cover it under smart lock installation. For locks built to resist picking, drilling and bumping beyond standard grades, see our page on high-security locks. And if you want the broader picture of new hardware on any door, our lock installation service covers handlesets, knobs and other locks beyond the deadbolt.
Deadbolt installation across Monrovia: older homes, townhomes and apartments
Monrovia is not one kind of door. North of Foothill Boulevard, including the streets in and around Old Town Monrovia and the hillside houses climbing toward the Monrovia Highlands, there is a deep stock of Victorian, Craftsman and early-1900s homes, and an active historic preservation program protects many of them. Those front doors are often solid, older and fitted with legacy hardware. Fitting a modern deadbolt into a door like that takes care: we check for existing bores, fill or plate old holes where needed, and keep the work as unobtrusive as we can. If your house falls under the preservation program, check what is allowed for visible exterior hardware before changing anything on the front of the door.
Around the Station Square area near the A Line, newer townhome projects have gone up, and their doors are usually prepared for standard deadbolts, so replacement is often a matter of matching the existing holes and upgrading the grade of the lock. A familiar local call is a townhome lockout in those newer developments; if you are locked out right now, our house lockout service is the first call, and we can talk deadbolt upgrades once you are back inside.
South Monrovia is mostly smaller postwar houses and apartment buildings, where a deadbolt that is tired, loose or keyed to a long list of past tenants is common. Apartment rekeys in South Monrovia complexes are a regular type of work, and deadbolt replacement often comes with it. Whether you are in 91016 near Huntington Drive, along Myrtle Avenue or off the Foothill Boulevard corridor, we work from the same method: look at the door first, then choose the lock.
The climate matters too. Monrovia sits in a San Gabriel Valley foothill climate with hot summers and periodic Santa Ana winds. The realistic effects on a deadbolt are heat-driven door swelling, which makes a bolt drag against a strike that fit fine in winter, and wind-blown dust that works into cylinders and slows them down. There is no coastal salt air here, so corrosion is not the concern. We set the bolt with a little working clearance and test it at the door's actual position, not just on the bench.
Locked out or need a locksmith now?
We answer around the clock, every day of the year.
Call (213) 577-1366Why call Wilshire Lock & Key for a deadbolt?
We have been in business since 1987, and we serve 140 cities across Los Angeles and Ventura counties, Monrovia among them. We operate a real storefront at 10740 Wilshire Blvd in Westwood along with mobile service vans, so the person who answers the phone works for the same company that sends the van. There is no dispatch middleman, no lead-selling site, and no stranger in an unmarked car you never spoke to.
David, the owner and lead technician, oversees our work. For a deadbolt job that means the details above, the clean bore, the reinforced strike, the test with the door closed, are the standard we hold ourselves to, not an optional extra.
Our phone line, (213) 577-1366, is answered 24 hours a day, 7 days a week, year-round. A deadbolt install is usually something you can schedule, but a broken or damaged one on your front door is not, and we treat it that way. If a door cannot be secured tonight, see our page on emergency locksmith help in Monrovia.
What should you ask any locksmith before they install a deadbolt?
Ask for their California BSIS locksmith company license. California requires locksmith companies to hold a Locksmith Company (LCO) license issued by the Bureau of Security and Investigative Services, and any honest locksmith will give you that number without hesitation. Our license number is being added to this site, and we are happy to talk about it when you call.
Beyond that, a few practical questions separate careful work from rushed work. Ask what grade of deadbolt they intend to use, whether the strike will be reinforced with long screws, and what happens if the door turns out to need repair. Ask who will actually be at your door. Be cautious of anyone who names a rock-bottom number over the phone before seeing anything, then adds charges once they arrive.
If you own rental property in Monrovia and need several doors done at once, with keying that makes sense for turnover, our page for locksmith for landlords explains how we handle multi-unit work.
Frequently asked questions
Can you install a deadbolt on a door that does not have one?
Yes. We measure the door, drill the face and edge holes with a jig, cut the latch recess, set the bolt and fit a reinforced strike plate. We first check that the door is thick and sound enough to take a deadbolt without weakening it. Hollow, damaged or very thin doors may need repair or a different approach, and we say so before starting.
What is the difference between a single-cylinder and a double-cylinder deadbolt?
A single cylinder has a key outside and a thumbturn inside. A double cylinder needs a key on both sides. Double cylinders are for doors with glass close enough to the interior hardware that someone could break it and reach in. The trade-off is that you need a key to get out, which can be dangerous in an emergency, so we only recommend it where the glass really justifies it.
Is a double-cylinder deadbolt allowed in my home or rental?
It depends on the building, how it is used, and your lease. Some situations restrict or discourage keyed-both-sides locks because of exit safety. We cannot rule on your specific property, but we will explain the safety concerns, and renters should check with their landlord or property manager before we install one.
Should I replace my deadbolt or just rekey it?
If the lock is in good shape and you only want different keys, rekeying is usually the more economical route. If the deadbolt is loose, worn, damaged, low-grade for the door it protects, or the wrong style for your needs, replacement makes more sense. We look at the lock and tell you which one it needs.
Do you install deadbolts on Victorian and Craftsman doors in Monrovia?
Yes. Older solid doors north of Foothill Boulevard take a deadbolt well when the prep is done carefully. We check for old bores or legacy hardware, plate or fill what we need to, and keep the work tidy. If your home is under Monrovia's historic preservation program, check what is allowed on visible exterior hardware first.
Why does my deadbolt stick in summer?
Heat can make a wood door swell slightly, so the bolt no longer lines up cleanly with the strike. Dust carried by Santa Ana winds can also slow the cylinder. Sometimes a small strike adjustment fixes it, and sometimes the hardware is simply worn. If it fights you every time, have it looked at before it fails with the door shut.
Can you key the new deadbolt to match my other locks?
In many cases yes. We can key a new deadbolt to work with a key you already carry, or set up several locks alike so one key covers your doors. Tell us what you have when you call and we will confirm what is possible with your existing hardware.
Do you come to Monrovia at night or on weekends?
Our line at (213) 577-1366 is answered 24 hours a day, 7 days a week, year-round, and we serve Monrovia from our Westwood storefront with mobile vans. If your door cannot be secured, call right away. For planned deadbolt work, tell us what you need and we will schedule it.
More locksmith help in Monrovia
Deadbolt Installation near Monrovia
Reviewed by David, Owner & Lead Technician, Wilshire Lock & Key — in the locksmith trade since 1987.
Last updated 2026-10-11.