I just moved into my new house and changed all the locks except one. The house was built in 1930 and the back of the house has a "mud room". The door into the house from the mud room is normal. The door into the mud room from the outside is 1 1/8" thick. I want to install a matching dead bolt like the rest of the house.

How can i install a dead bolt into a thin door?

The best thing i can think of is to install "decorative" plates on the inside and outside of the door to make up the thickness before drilling for the lock. The only draw back being that i will have to notch out molding where the extra thickness would be.

  • The item normally termed a "deadbolt" is a 1" thick bar attached to a key cylinder used to secure exterior doors. Is that what you mean by "deadbolt"? Why do you want to install one on an interior door? The other doors in the house also have deadbolts installed?
    – Chris M.
    Commented Jun 27, 2017 at 20:16
  • @ChrisM. Other way around. An interior door already has a deadbolt. I want to put one on the exterior door.
    – vini_i
    Commented Jun 27, 2017 at 20:18
  • Ah, now I understand. Presumably, the intent of the deadbolt between the mud room and the house is to mitigate the lack of ability to install a modern deadbolt in the thinner exterior door.
    – Chris M.
    Commented Jun 27, 2017 at 20:25
  • @ChrisM. The mud room is not over the basement of the house. It may have been an add on after the house was built. This may also explain why there is an exterior door between the mud room and the house.
    – vini_i
    Commented Jun 27, 2017 at 20:32

2 Answers 2


To my knowledge, you won't find any modern in-door deadbolts that can accommodate such a thin door. Even if you padded the width of your door around the installation point to reach the minimum needed, drilling the hole for the deadbolt will essentially remove a notch from your original door (deadbolts are commonly 1" thick). Your spacers will have to go all the way to the edge of the door to conceal the deadbolt.

A simpler solution would be to use a surface-mount deadbolt, which requires only that you drill a hole for the rim cylinder. You may have to add a spacer around the rim cylinder to get a flush fit, but it won't end up being the only thing concealing the lock mechanism from tampering. That link shows several types, including jimmy proof deadbolts and night latches.

  • The idea of using a surface-mount deadbolt is a great one. The OP did say he wanted to use the same type of deadbolt he had for the other door, but I think he could reconsider. Commented Jun 27, 2017 at 21:52
  • 1
    @JimStewart The door is actually already equipped with a Rim dead bolt. I changed all the locks in the house to Shclage and I could not find a Schlage made Rim deadbolt. After a conversation with my local key shop, they have Schlage sile Rim lock cylinders and they can rekey them to my key. This way all i have to replace is the cylinder and keep the existing lock.
    – vini_i
    Commented Jun 29, 2017 at 12:17

We have a 1-1/8" thick solid oak framed screen door bought from a custom door manufacturer. The company supplied a small handle set w/ slide lock with instructions for drilling for the handle and bolt holes, which I followed. It sounds to me like your door into the mudroom was originally intended for that kind of light duty door lock.

To install a standard deadbolt I would attach suitable pieces of 1/2 inch plywood on the inside of the door and the jamb and proceed to cut holes according to the instructions for the deadbolt.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.