Clera Windows + Doors Blog

How to Replace Door Locks

Replacing door locks is straightforward enough for most homeowners to safely do it by themselves. Most door locks come with instructions from the manufacturer on how to install the lock.

So whether you just need a replacement door lock because of a new housemate or because the old one is already worn out, this article covers the steps you need to take. Along the way, we will also touch on the main types of door locks.

Let’s get started!

Closeup of a rusty old door lock that needs to be replaced

Becoming Familiar with the Types of Door Locks

For most residential property doors, there are two main types of door locks used: knob lock and deadbolt locks. 

Knob Lock

The knob lock is the most common type of lock that you will see in various properties. By themselves, however, they are only used for interior doors because even basic tools like a hammer or wrench can be used to break into these locks. Knob locks have the lock cylinder in between the two knobs attached to the door.  

Deadbolt Locks

Deadbolt locks are often used for exterior doors (sometimes along with knob locks) because they provide the best protection against a break-in. The locking mechanism of deadbolt locks are able to provide the most resistance to battering and boring. There are three main types of deadbolt locks that you should know about: single cylinder deadbolts, double cylinder deadbolts, and the lockable thumbturn

Single Cylinder Deadbolts

The single cylinder deadbolt lock has a key cylinder on the external side and a thumbturn on the internal side. Because of this design, the primary weakness of these locks is that if access to the internal side is granted (e.g. through an open window), the front door can be opened using the thumbturn. 

Double Cylinder Deadbolts

To address the security weakness of the single cylinder deadbolt, double cylinder deadbolts use a key cylinder on both the internal and external sides of the door. However, it still has a disadvantage of requiring a key to open the door even from the inside of the house if it is locked. This can be a serious problem if there should be a fire or any similar emergency. 

Lockable Thumbturn

The lockable thumbturn is sort of a mix between the first two types of deadbolts that we discussed. It has a thumbturn on the internal side that also functions like the one in a single cylinder deadbolt – the difference is that this thumbturn can also be locked using a key.

So this means that if people are inside, the thumbturn can be just used regularly (not locked), and it will still lock the door from the external side – just like with a single cylinder deadbolt. 

However, if everyone will leave the house and the house would then need added security, the thumbturn can be locked – this way, even if a burglar breaks in through a window and tries to open the door from the inside, the door will remain shut.

The side view of a deadbolt lock with a knob lock

How to Replace Door Locks in 5 Steps

So now, we move on to the whole process of replacing the lock. We will follow this sequence of steps:

  1. Remove the old lock
  2. Measure the door’s hole for a new lock
  3. Place the old lock back temporarily (an optional step)
  4. Purchase the correct size of lock
  5. Install the new lock  

1. Removing the Lock

Removing the Knob Lock

  1. Remove the old knob lock by first loosening the screws that attach it in place. This can be found on the internal side of the knob lock. 
  2. As you loosen the screws, you will notice that the both knobs will start to fall off – you can hold them so that they do not fall to the floor.
  3. The internal knob will slide out easily. However, to allow the external know to slide out, simply press the latch on the side of the door inward and this will allow the external knob to be pulled right through. 
  4. Lastly, remove the entire latch assembly by unscrewing the screws of the latch plate and pulling the assembly out. 

Removing the Deadbolt Lock

  1. From the internal side of the deadbolt lock, remove the screws. 
  2. If you cannot see any screws at all, you would need to remove the protective plate (that some locks have) which is hiding the screws. To do this, you would need a correctly-sized allen wrench to remove the thumbturn. Once the thumbturn is removed, you can easily pry the protective plate out with a screwdriver and you will see the screws that you need to access. 
  3. Next, unscrew the plate of the bolt itself. Once unscrewed, this should slide out easily. 

2. Measuring the Door for a New Lock

These steps are the same for both knob locks and deadbolt locks. 

  1. Before buying a replacement lock, it is important to first make a few measurements – so have your tape measure ready.
  2. Remove the old lock (see steps above)
  3. Measure the diameter of the hole that holds the lock along with the distance from its center to the door’s edge. 
  4. You can put your old lock back on momentarily as you purchase a new one that will fit the door. This is IF the lock is still in the condition to be placed back. If you don’t need to reposition your lock, you can bring it along to the hardware store to help you purchase a correctly sized lock.  

3. Purchasing a New Lock

  1. When purchasing a new lock, refer to the measurements from the previous steps. You can ask for help in the hardware store as long as you have the measurements handy.
  2. Once you have your new door lock and you have gone home, first check if it comes with the cardboard template that shows you how the lock will fit your door. Fold this template along your door’s edge to see if the diagram aligns with the hole on the door. 
  3. If the cardboard template aligns perfectly with your door then you don’t have any problems and you can continue installation. However, if the diagram on the cardboard template does not match, you would need to go back to the hardware store, bring your old lock along, and ask for help in finding a replacement lock that really fits.

4. Installing the Lock

If you have already purchased a lock that is right for your door’s lock hole, you can now follow these easy steps to install it. 

You can also follow along these same steps to reattach an old lock (which you might want to do as you purchase a new one) – as long as the lock is in good enough condition to be reinstalled.  

Installing a Knob Lock

  1. Slide the latch assembly through the side of your door. Make sure that the curve side of the latch faces the door’s frame. 
  2. Then, screw the latch plate securely. 
  3. Next, put in the external knob (the one with the key slot) and make sure it is facing outside. 
  4. Then, take the internal knob and align it carefully. When aligned correctly, the screws should thread through securely and not sink in or fall out. 
  5. Tighten the screws in place.  
  6. Test your doorknob.

Installing a Deadbolt Lock

  1. Slide in the bolt through the side of the door. If you have bought a correctly sized deadbolt lock, this should line up with the hole of the door. T
  2. hen, screw the bolt plate securely. 
  3. Next, make sure that the correct piece is going to be on the external and internal side of the door. 
    1. For a single cylinder deadbolt lock, the thumbturn needs to be on the internal side. 
    2. For a double cylinder deadbolt lock, the cylinder with the screw holes needs to be on the internal side. 
    3. For a lockable thumbturn, the thumbturn needs to be on the internal side.
  4. Once everything is aligned properly, both sides should meet seamlessly in the middle. The screws should thread through securely and not sink in or fall out. 
  5. Tighten the screws in place. 
  6. Test your deadbolt lock. 

Conclusion

And there you have it! Easy steps to replace your door knob or deadbolt lock. Let us know in the comments below if you have any tips or tricks you’d like to share when to comes to replacing and installing new door locks.

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