Do you need a new deadbolt, or just a better-fitted one?
Most calls we get about deadbolts fall into a few groups. Some doors have no deadbolt at all, only a knob or lever latch that a flat tool can slip. Some have a deadbolt that is worn, loose, or dragging. Others have one that works fine but was set up years ago, and the owner has no idea who holds copies of the key. Each of those is a different job, and it is worth sorting out which one you have before anyone drills a hole in your door.
A deadbolt is the part of your door that does the real work against forced entry. A spring latch holds the door shut against the weather, but a deadbolt throws a solid steel bolt into the frame and stays there until a key or thumbturn pulls it back. When it is installed well, the door is hard to kick in and hard to pry. When it is installed badly, with a crooked bore, a short strike screw, or a bolt that barely catches the frame, it looks secure and is not.
That is why this page is about the installation itself: choosing the right style, boring and fitting it cleanly, and aligning the bolt so it throws without a fight. If you only want the existing lock to accept a different key, that is a lock rekey, a smaller job than a new deadbolt. If the whole lockset is worn out, lock replacement may be the better fit. We will tell you which one your door actually needs.
What is the difference between single and double cylinder deadbolt installation?
A single-cylinder deadbolt has a keyway on the outside and a thumbturn on the inside. You lock and unlock from indoors with your hand, no key needed. This is the standard choice for most homes because anyone inside can leave quickly, including in a fire or emergency.
A double-cylinder deadbolt has a keyway on both sides, so it takes a key to lock or unlock from inside as well. People ask for double cylinder deadbolt installation when there is glass in or beside the door. The reasoning is that a burglar who breaks the glass cannot simply reach in and turn a thumbturn. It is a legitimate use, but it comes with a real trade-off that we explain before we install one.
- Single cylinder: key outside, thumbturn inside. Fastest to exit, the usual recommendation for bedrooms, main entries, and most exterior doors.
- Double cylinder: key on both sides. Makes sense next to sidelights, a glass panel, or a window you cannot reinforce, but only if everyone in the home can get to a key quickly.
- Keyed-both-sides locks on a door you rely on as an exit can be restricted by building and fire codes, rental rules, or HOA rules. We cannot rule on your specific case, so check with your landlord, HOA, or the local building department before choosing one for a primary exit.
- If you want a double-cylinder lock, a common safety habit is to keep a key in a known spot near the door, out of reach from the glass. We will talk through what is practical for your household.
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Call (213) 577-1366How do we install or replace a deadbolt, step by step?
Whether we are adding a deadbolt where none exists or doing a deadbolt replacement on a worn one, the sequence is similar. The door is not a blank board. It has a thickness, a finish, and sometimes a previous owner's mistakes, and each of those affects how we proceed.
- Look at the door and frame. We check the door material, thickness, condition of the edge, whether it sags, and what is already drilled into it. A hollow or damaged door may need reinforcement before a new lock will hold.
- Confirm the hole sizes. Most residential deadbolts use a standard cross-bore hole through the face of the door and a smaller bore into the edge. We measure the backset, the distance from the door edge to the center of the bore, so the new lock lines up with what is already there or with the correct new layout.
- Choose single or double cylinder with you. We go over the exit and glass question above, then pick a lock body, finish, and grade that matches how the door is used.
- Remove the old hardware or mark and bore the new holes. For a replacement, we take out the old lock and check the bores for chipped wood or oversized holes. For a new installation, we use a template and a hole saw, drilling from both faces to avoid splintering.
- Fit the latch and strike. The bolt goes into the door edge and the strike plate into the frame. We set the strike so the bolt lands centered in its hole, and we use long screws that reach the wall stud rather than just the thin door jamb.
- Mount the cylinder and interior piece. The two halves connect through the door, and we tighten them evenly so nothing binds.
- Test it under real conditions. We run the bolt with the door open, then closed, then pulled against the frame the way a stuck door would be. Smooth throw, full extension, no scraping. We also test every key and the thumbturn.
- Hand over the keys and explain the lock. You get a clear walkthrough of how it works, what to watch for as the door ages, and what to call us about if it starts to drag.
What affects the cost of deadbolt installation in Simi Valley?
We do not quote numbers on a web page, because the honest answer depends on the door in front of us. What we can do is tell you exactly what moves the cost, so a quote over the phone makes sense when you hear it.
The biggest factor is whether this is a replacement or a new installation. Swapping a deadbolt into existing holes is a lighter-cost job than drilling a new bore into a door that never had one. The next factor is the lock itself: a basic residential grade, a heavier-duty grade, and a high-security cylinder with restricted keys are different products with different prices behind them.
Other things that change the total include:
- Door material and condition. Solid wood, hollow-core, steel, and fiberglass all drill differently, and a damaged edge or door that no longer sits true may need repair first.
- Single versus double cylinder, and whether you want the cylinders keyed alike with another lock on the property.
- Reinforcement. A longer strike, a reinforced strike box, or a door-edge plate adds parts and labor, and it is often the most worthwhile upgrade.
- How many doors. Doing the front, back, and garage entry in one visit usually makes better use of the trip than separate calls.
- Finish matching. If the new deadbolt has to match existing handles, or satisfy HOA hardware rules, the selection takes more care.
- Timing and location. A late-night call to a hillside street costs us more to reach than a planned daytime visit, and the quote reflects that.
- Our approach is to describe the work, name the parts, and give you a quote before we start. If a lighter-cost option will do the job well, we will say so. We would rather install the right lock once than sell you something your door cannot support.
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Call (213) 577-1366Which deadbolt should you choose: grade, bolt length, and strike plate?
Deadbolts are rated by the American National Standards Institute and the Builders Hardware Manufacturers Association. Grade 1 is the toughest, Grade 2 is solid residential duty, and Grade 3 is the lightest. Many hardware-store deadbolts sit at the lighter end. For an exterior door that faces a street or a side yard, we usually lean toward a stronger grade, but that depends on the door, the budget, and what the lock needs to withstand.
Bolt length matters more than people expect. A bolt that extends about an inch into the frame is far harder to defeat than one that barely clears the edge. But the length only helps if the frame behind the strike is solid. A strike plate fastened with short screws into a thin jamb is the weakest part of many entry doors, and a kick can split it open no matter how good the lock is. We almost always install longer screws that bite into the framing behind the jamb.
If you want a keyless or app-connected option, that is a different product category. We cover that on our smart lock installation page. If your priority is pick resistance, restricted key control, or drill protection, look at high-security locks instead of a standard deadbolt.
What should Simi Valley homeowners know about deadbolts on local doors?
Simi Valley is mostly a place of single-family homes. The valley floor is covered in 1960s and 1970s ranch tracts, with 1980s through 2000s master-planned housing in Wood Ranch and newer hillside homes in Big Sky. That mix shapes deadbolt work in a few predictable ways.
In the older tract neighborhoods in the 93063 and 93065 ZIP codes, we often meet doors that have been through decades of use. The door may have been refinished, the strike area may have been patched, and the bore may have been enlarged by a previous lock swap. A new deadbolt here often starts with checking whether the door still has enough sound wood around the holes. Tract homes also change hands, and after a sale, new owners frequently want fresh locks. If you only need the keys changed, that is a rekey. If you want a stronger, better-fitted lock at the same time, a deadbolt installation is the natural moment to do it.
In Wood Ranch, new homeowner lock packages are a common scenario. HOAs are common in the newer west-end communities, and some have rules about exterior hardware finish. If you live in an HOA, ask what is allowed before you pick a finish, and tell us when you call so we can bring the right options. A new owner can also have us install matching deadbolts on every exterior door in one visit, keyed so one key works for all of them.
Climate plays a bigger part than people realize. This inland valley has hot, dry summers and Santa Ana wind events that funnel through the Santa Susana Pass. Strong sun and repeated heating and cooling cycles make doors expand and contract, and they fade or stiffen exterior hardware on south-facing entries. That is a routine cause of a deadbolt that used to slide easily and now drags, or a bolt that no longer meets the strike. In those cases the problem is often alignment, not a failed lock, and part of our install work is setting the strike so there is a little tolerance for seasonal movement.
Bridle Path is an equestrian neighborhood with large lots and horse gates. A gate latch and a deadbolt are different tools. If your question is about a gate, take a look at gate lock repair. If it is a barn or tack-room door, a deadbolt may suit it, and we will look at the door and weather exposure first. In Santa Susana Knolls, which holds older custom hillside homes on winding streets, doors tend to be custom-sized, so we measure before assuming a standard lock will fit. Our mobile vans cover the area from our Westwood base, about 35 miles away, and we will tell you plainly when we call what the drive means for scheduling.
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 the work has not changed in its basics: a good lock on a bad door is wasted money, and a careful install on a decent door is worth it. David, the owner and lead technician, oversees how we do this work, from the bore measurements to the strike alignment.
We run a storefront at 10740 Wilshire Blvd in Westwood and mobile service vans, so the person you talk to is part of the same company that comes to your door. There is no dispatch middleman reselling your call to whoever is available. We serve 140 cities across Los Angeles and Ventura counties, and Simi Valley is one of them.
The phone, (213) 577-1366, is answered 24 hours a day, seven days a week, year-round. That matters if a break-in damaged your door at night and you need it secured right away. For planned work, call during the day and we can talk through the door and choose the hardware before anyone arrives. For general home work beyond deadbolts, see our residential locksmith page.
How do you check that a locksmith is properly licensed in California?
California requires locksmith companies to hold a license from the Bureau of Security and Investigative Services, known as a BSIS Locksmith Company (LCO) license. Ask any locksmith you are considering for the license number, and check it with BSIS before they start work. A legitimate company will give it to you without hesitation.
A few other signals are worth watching. Be careful with anyone who will not tell you the company name on the phone, who quotes a very low figure and then raises it at the door, or who wants to drill out a lock that could have been picked or reused. Ask for the job description and parts in writing or by text before work begins, and ask who will actually arrive.
What if you are locked out or the deadbolt fails?
A deadbolt that jams in the locked position can turn into a lockout, and a lockout is a separate situation from an installation. If you are outside your home right now, see our house lockout service, and we will start there. Once you are inside, we can look at why the deadbolt failed and whether repair, replacement, or a fresh installation is the right path. If you would like us to come to you, our mobile locksmith service covers how that works.
Frequently asked questions
Can you install a deadbolt on a door that does not have one?
Yes, in most cases. We check the door's thickness, material, and condition, then bore a new cross-bore and edge hole using a template, install the bolt, and set a strike in the frame. Thin hollow doors or damaged edges may need reinforcement first, and we will tell you before we drill.
What is the difference between deadbolt installation and deadbolt replacement?
Installation means adding a deadbolt where there is none, which involves drilling new holes. Replacement means swapping an existing deadbolt, often into the same holes, which is usually less work. If the old holes are damaged or the wrong size, a replacement can turn into a repair job on the door.
Should I get a single or double cylinder deadbolt?
Most homes should use single cylinder, with a key outside and a thumbturn inside, so you can exit quickly. Double cylinder makes sense when glass sits within reach of the lock, but a key is needed to exit. Check building, fire, rental, and HOA rules before choosing one for a main exit.
How long does a deadbolt installation take?
A straightforward replacement into existing holes is usually quick. A new installation takes longer because of drilling, fitting the strike, and testing. Doors that need repair or reinforcement take more time. When you call, describe the door and we will give you a realistic sense of the visit.
My deadbolt sticks in summer. Does it need replacing?
Not always. Simi Valley's heat can make doors expand and hardware stiffen, especially on south-facing entries, which pulls the bolt out of line with the strike. Often the fix is adjusting or re-setting the strike, or lubricating and checking the door. We will tell you whether the lock itself is worn out.
Do I need to ask my HOA before changing a deadbolt?
If you live in an HOA community, such as the newer west-end developments, it is smart to check. Some HOAs set rules about exterior hardware finish or style. Tell us what finish is required and we can bring options that fit, so the new lock does not have to be swapped later.
Can you make all my deadbolts use one key?
Yes. We can install or key multiple deadbolts alike so one key opens the front, back, and garage entry doors. If you already have locks you want to keep, we can often rekey them to match. Ask when you call and we will plan the visit around it.
Is a deadbolt enough, or should I add anything else?
A deadbolt is only as strong as the door and frame around it. Longer strike screws, a reinforced strike, and a solid door make a major difference. If you want keyless entry or pick-resistant cylinders, we can discuss smart locks or high-security options, depending on your goals.
Do you install deadbolts at night or on weekends in Simi Valley?
Our phone line, (213) 577-1366, is answered 24 hours a day, seven days a week, year-round. If a forced entry has left your door unsecured, call right away. For planned installs, daytime calls let us talk through the door and choose the hardware before the visit.
More locksmith help in Simi Valley
Deadbolt Installation near Simi Valley
Reviewed by David, Owner & Lead Technician, Wilshire Lock & Key — in the locksmith trade since 1987.
Last updated 2026-10-11.