Fitting a Security Chain - Secure Your Front Door and Your Home with a Security Door Chain

Summary: How to attach a security chain to your front door. Security chains allow you to partially open the door to talk to strangers and find out why they have knocked. If set properly they will allow the caller to pass you an identification card if necessary but it will not open wide enough for them to gain entry without your permission. The security chain gives you full control over who enters your home. In this DIY guide we show you how you can fit a door chain in 3 easy to follow steps and ensure your home is safe and secure.

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Step 1: Fitting the Security Door Chain to the Frame

The first step is to locate the strongest part of your door. Usually this is wide rail fitted horizontally in the centre of the door, called the lock rail.

Not all doors feature this so if yours doesn't, don't worry. Given that it is an external door you are fitting your security chain to, it will have very strong upright rails, or door jambs as they are called, so you will be fine to fix it in place here.

The lock rail for an external door is designed to receive mortice locks and latches so needs to be a little thicker than the rest of the door, as the mortice lock itself is quite wide.

Parts of an external door

How to identify the different parts of an external door

Having decided where the main chain keep will go, look to the door frame to position the chain. The chain bracket can be fitted horizontally as shown in the image below, or it can be fitted vertically if needed.

Most security chains are made to similar dimensions, so if you are thinking of buying one check that you have at least 34mm of door frame showing on the closing side (leading edge) of your door.

Door lock positioned horizontally

Dimensions of a standard door lock positioned horizontally

Hold the chain bracket to the frame, opposite the top half of the lock rail (A). The reason we fit to the top half of the lock rail (B) is because the letterbox is usually fitted in the centre of this rail. With a big hole cut for the letter box, the centre of the rail is marginally weaker than the timber top and bottom which run straight through the mid section of the door without interruption.

The lock rail of an external door

Identifying the wide lock rail of an external door

Mark the position of the screw holes for the chain. As mentioned it does not matter if the chain is fitted vertically or horizontally, it depends on the room you have available on the frame. What does matter however is that when the security chain is not being used it is fitted in a way which allows the free end to be hung in the chain bracket slot. This saves it dangling about and getting caught between door and frame which could potentially damage the door and also the frame.

How to mark out for the bracket on a door security chain

Marking position of screw holes for security chain bracket

Drill pilot holes for the door chain bracket screws. Make sure you use screws which are at least 1-inch (25mm) long.

Quite often the screws sent with the chain are simply not long enough for the job and could easily rip out if the door was given some abuse. See our project on Pilot Holes and Countersinking here.

Drill pilot holes for security chain bracket

Pilot holes make it easier to fix a security chain bracket

Fix the security chain bracket with a screwdriver into the pilot holes you have just created. Be careful if you use a battery operated screwdriver in this position as the door frame is very often close up to the door reveal and, if the screws are driven in straight as they really should be, the spinning of the drill chuck could easily rub against the door reveal as do some damage.

In the video below you will see us fitting the screws in at a slight angle. One reason for this is that a door chain had been fitted on this door before but the screws were too short and the chain got ripped out. We therefore screwed in at an angle to ensure we were getting the best fix possible.

Fitting security chain bracket with a screwdriver

Use a screwdriver to fit security chain bracket

Hang the security chain in the slot provided (A in the image below) to keep it out of the way for step 2.

Make sure the security chain cannot damage the door

Keeping the security chain out of the way will reduce risk of damage to the edge of the door

The security door chain bracket is designed so that when the chain is not in use it can be hung up, out of the way in the spare section of bracket (A). This stops it accidentally swinging in between the door and the frame and damaging the edge of either, or both.

Close up of security chain frame bracket and position of the chain

The position of the security chain bracket must allow for safe keeping of the chain

Step 2 - Fitting the Security Door Chain Keep to the Door

Place the security chain keep onto the lock rail of the door opposite the chain bracket you have just fixed. Drop the chain into it. Slide the fitting towards the centre of the door so that the chain tightens up but you are still able to lift it out when the door is closed.

Set the position of the security door chain keep

Mark the keep position of the security door chain by sliding it along the lock rail until you are happy

The door should not be allowed to open wide enough for even the tiniest hand to be able to lift the chain out of its retaining bracket.

In most cases this will mean that the front edge of the keep will be about 50mm from the edge of the door. The nearer the edge of the door you place the keep, the wider the door will open when the chain is locked in its closed position.

When you have established exactly where the keep needs to go so that it can easily be fitted and removed from the keep and also prevent the door from opening too widely, mark its final position.

Mark position of security chain keep with a pencil

When you are sure of position of chain keep and mark it

Hold the keep in position or mark the holes if needed with a pencil or pen. Additionally, before marking them, use a small spirit level such as a boat float to make sure the keep is level.

Once you have ensured it is level and you have made your marks, drill your pilot holes as before.

Drilling pilot holes to fit security chain keep

Drilling pilot holes for security chain keep

With your holes now drilled you can fix the keep into its final position.

Fitting a security door chain keep into position

Carefully screw a security door frame keep into position

Step 3 - Testing the Fit of Your Door Security Chain

When you have finished screwing the door chain keep into position, drop the chain into the slot and open the door. Ask a friend or partner to try and remove the chain, from the outside, while the door is open. If you have followed the two previous steps properly and watched the video of course..... They will not be able to get in..... Pat your self on the back for a job well done!

A fully fitted door security chain

security door chain completely fitted

Foiling burglars with well fitted door security chain

A well fitted and secure door chain will help to foil burglaries - Get your door chain now from our online store here

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