What does a proper deadbolt installation actually involve?
A deadbolt is only as good as the way it sits in the door. The hardware can be excellent, but if the bolt rubs the strike plate, the screws are short, or the hole is bored a little crooked, you end up with a lock that sticks in summer, gets forced in a hurry, or kicks in on the first hard shove. Most of what we do on a deadbolt call is not exotic. It is careful measuring, clean boring, and alignment.
Some Sylmar customers call because a door has never had a deadbolt and only has a knob lock. Others have a deadbolt that is worn out, loose, or keyed to a stranger's old set of keys. Some are renters or new owners who want the entry doors to be solid before the first night in the place. In every case the job comes down to the same question: what is this door made of, how thick is it, and what kind of lock suits the way you live?
This page covers installing a new deadbolt and replacing an existing one. If you are locked out right now, our house lockout service is the place to start, and we can talk about the deadbolt once you are back inside.
Single-cylinder or double-cylinder: which deadbolt fits your door?
The cylinder type is the first decision, and it is where we spend the most time talking with customers, because the wrong choice can cause real problems later.
A single-cylinder deadbolt takes a key on the outside and has a thumbturn on the inside. It is the right answer for the large majority of solid entry doors. You can leave the house quickly, and nobody who reaches in through a broken window pane can open it without a key.
A double-cylinder deadbolt takes a key on both sides. We install these most often on doors with glass in or beside them, where a thumbturn within arm's reach of the glass would defeat the lock. The tradeoff is real: if the key is not in the lock, you cannot get out in a hurry during a fire or emergency.
- Choose single-cylinder for solid doors, bedrooms-side exits, and anywhere a fast exit matters.
- Consider double-cylinder for doors with glass panes or sidelights within reach of the inside hardware.
- Check your rules first. Fire and building codes in many places restrict keyed-both-sides locks on residential exit doors, and landlords or HOAs often set their own rules. We will tell you what we know, but confirm with your landlord, HOA, or the local building department if you rent or live in a managed community.
- If you do use a double-cylinder, keep a key in a safe, known spot near the door and make sure everyone in the home knows where it is.
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Call (213) 577-1366How we install a deadbolt, step by step
Whether we are adding a deadbolt where none existed or swapping an old one, the sequence is much the same. Here is how a typical visit goes.
- Look at the door. We check thickness, material (solid wood, hollow core, metal, or fiberglass), condition of the edge, and the frame. A cracked or rotted door or jamb changes the plan.
- Talk through the lock. We confirm single or double cylinder, the security grade you want, and whether you want it keyed to match other locks on the property.
- Mark and bore. For a new installation we mark the height and use a template to drill the standard cross bore and the edge bore for the bolt. For a replacement, we confirm the existing holes match the new lock and correct them if they do not.
- Install the latch and lock body. The bolt goes in square, the faceplate sits flush, and the cylinder pieces connect without forcing.
- Fit the strike plate. We chisel the jamb so the strike sits flush, then drive long screws that reach the wall framing rather than only the thin jamb. This is what turns a deadbolt from decoration into real resistance.
- Test it. We cycle the bolt with the door open and closed, check that it throws fully without rubbing, and confirm every key works. If the door has swelled or shifted, we adjust before we leave.
- Hand over keys and explain. You get the keys, and we point out anything about the door itself that needs attention.
Deadbolt replacement: when a swap makes more sense than a repair
A deadbolt that is stiff, loose on the door, or hard to turn is not always ready for the trash. Sometimes it needs adjusting, or the door has moved and the strike needs to be shifted. If the problem is a worn part or a misaligned bolt, a repair may be the more economical route, and we will say so. Our lock replacement page explains how we think about repair versus replacing in general.
Deadbolt replacement is the better call in a few situations: the lock is visibly worn or corroded, the key turns but the bolt does not move reliably, the lock is a low-grade model that you want to upgrade, or the cylinder was damaged during an attempted break-in. It is also sensible when you do not know how many copies of the old key exist.
If the existing lock is in good shape and your main worry is who has keys, rekeying may be enough. We cover that on our lock rekeying page. Rekeying changes the inside of the cylinder so old keys stop working, without buying a new deadbolt.
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Call (213) 577-1366What affects the cost of deadbolt installation in Sylmar?
We do not quote numbers on a web page because the honest answer depends on your door. When you call (213) 577-1366, we ask a few questions so the quote you hear reflects your situation. These are the factors that move the cost up or down.
- New installation versus replacement. Boring a fresh door takes more work than swapping a lock into holes that already fit.
- Door material and condition. Solid wood, metal, and fiberglass doors are all bored differently, and a damaged door edge may need repair first.
- Security grade of the hardware. A heavier-duty deadbolt with a reinforced strike costs more than a basic residential model. Our high-security lock options go further for people who want pick and drill resistance.
- Single or double cylinder. Double-cylinder hardware is a different product and usually costs somewhat more.
- Number of doors and keying. Several doors keyed alike takes extra setup but saves you carrying a ring of keys.
- Time of day and distance. A late-night visit or a longer drive takes more of our time than a scheduled daytime job.
- Frame work. If the jamb is split or the strike area is weak, reinforcing it is part of making the lock actually hold.
What do deadbolts look like on Sylmar homes?
Sylmar's housing is a real mix, and the right deadbolt job changes with the building. Much of the ZIP code 91342 is postwar through 1980s tract housing. Those homes often have original front doors that have been repainted many times, and an older knob-and-deadbolt pair that may have been replaced once or twice. Around Los Angeles Mission College, we see the pattern that goes with that: someone buys or rents a tract home, and the first thing they want is a solid deadbolt on the entry door with keys nobody else holds. Adding or replacing a deadbolt is often paired with rekeying the rest of the house after a move-in.
Near the Foothill Boulevard corridor there are newer gated townhome and small-lot developments. The doors there are usually newer, but HOA rules may limit what hardware you can put on the front. Check the rules before choosing a finish or a double-cylinder model, and we can work with what the community allows.
Farther toward the foothills, near Kagel Canyon and Lopez Canyon, and on the larger lots along corridors like Glenoaks Boulevard and Hubbard Street, you will find long driveways, detached garages, and perimeter gates. A side door on a detached garage deserves a real deadbolt as much as the front door does. For the gate itself, see our gate lock repair page. Sylmar also has several large mobile home parks, where the entry doors are lighter than a standard house door and the hole spacing is not always standard. We check the door before promising a particular lock will fit.
We are based at 10740 Wilshire Blvd in Westwood, about 24 miles from Sylmar, and our mobile vans come to you. See our mobile locksmith service for how that works.
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Call (213) 577-1366How do Sylmar's heat and wind affect a deadbolt?
The northern end of the Valley gets very hot in summer, and that matters for deadbolts more than people expect. Wood doors can warp in the heat, and weatherstripping loosens. A door that closed cleanly in spring may drag in August, and the bolt no longer lines up with the strike hole. That is usually a strike plate adjustment, not a bad lock, and we check it during any installation so the alignment is right for the door as it sits now.
Strong Santa Ana winds funnel through Newhall Pass and the foothill canyons and push dust into exposed hardware. Deadbolts on a covered front door are mostly shielded, but locks on side doors, patio doors, and gates take the dust directly. If your deadbolt is on an exposed door, we can point you to hardware that handles that better, and a little dry lubricant, not oil, helps keep dust from caking in the cylinder.
Why call Wilshire Lock & Key for your deadbolt?
We have been in business since 1987, and we serve 140 cities across Los Angeles and Ventura counties, Sylmar among them. A few things about how we work are worth knowing before you call.
You deal with one company. There is no call center passing your job to an unknown contractor. The same business that answers the phone at (213) 577-1366 sends the technician, and David, our owner and lead technician, oversees the work. We have a Westwood storefront at 10740 Wilshire Blvd and mobile vans for house calls, so we can handle both a quick part pickup and a full on-site installation.
We answer 24 hours a day, 7 days a week, year-round. Most deadbolt jobs can be scheduled, but if a break-in or lost key means your door will not secure tonight, call. Our residential locksmith page covers the rest of what we do for homes, and our Sylmar page has the local overview.
We also tell you when a deadbolt is not the answer. If the door or frame is the weak point, we say so. If a lighter-cost option does the job, we recommend it. If you are thinking about keypad or app-controlled hardware instead, our smart lock installation page is where that conversation lives.
How to check any locksmith before they touch your door
California requires locksmith companies to hold a BSIS LCO license, issued through the Bureau of Security and Investigative Services. Ask any locksmith you call for their license number, and look it up before work begins. Also ask for a full quote before the technician starts, confirm who is actually coming, and be wary of anyone who wants to drill out a lock that could be opened or replaced more simply.
For a deadbolt installation, a reasonable technician should be able to tell you the door type, the lock grade, whether it is single or double cylinder, and what is included. If those answers are vague over the phone, keep looking.
Frequently asked questions
Can you install a deadbolt on a door that doesn't have one?
Yes, in most cases. We check that the door is thick enough and solid enough to take the bore holes, then drill, install, and fit the strike into the frame. Hollow or damaged doors may need repair or reinforcement first, and we will tell you before we start.
What is the difference between a single-cylinder and a double-cylinder deadbolt?
A single-cylinder deadbolt uses a key outside and a thumbturn inside. A double-cylinder deadbolt needs a key on both sides. Double-cylinder locks make sense mainly for doors with glass nearby, but they can slow your exit in an emergency, so check fire code and HOA or landlord rules before choosing one.
Are double-cylinder deadbolts allowed on a home in Sylmar?
It depends on the building, the type of door, and the rules that apply to you. Many places restrict keyed-both-sides locks on exit doors, and landlords and HOAs often have their own rules. We can explain what we know, but confirm with your landlord, HOA, or the local building department.
Do I need a new deadbolt or just rekeying?
If the deadbolt is in good condition and you only want old keys to stop working, rekeying is usually the more economical route. If the lock is worn, damaged, low-grade, or you want an upgrade, replacement makes more sense. We will look at the lock and tell you which fits.
Will a new deadbolt fit my existing door holes?
Often yes, since most residential doors use a standard cross bore and edge bore. Older doors, mobile home doors, and doors that were modified before may not match. We check the holes and door thickness before choosing the lock, and we correct the holes when they are off.
Why does my deadbolt stick in the summer heat?
Heat can swell or warp a wood door and shift it slightly in the frame, so the bolt no longer lines up with the strike hole. That is often fixed by adjusting the strike plate rather than replacing the lock. If the lock itself is worn, replacement may be the better call.
Can you install a deadbolt on a mobile home door?
Usually, yes, but mobile home doors are often lighter and the hardware spacing is not always standard. We examine the door first and choose a lock that fits properly, rather than forcing a standard model onto it.
Do you install deadbolts at night or on weekends?
Yes. We answer the phone at (213) 577-1366 around the clock, every day of the year. Most deadbolt jobs can wait for daytime, but if a door cannot be secured tonight, call and we will work out the next step. You can also reach us through our contact page.
More locksmith help in Sylmar
Deadbolt Installation near Sylmar
Reviewed by David, Owner & Lead Technician, Wilshire Lock & Key — in the locksmith trade since 1987.
Last updated 2026-10-11.