How To Fit A Letterbox
Whether you’ve bought a new wooden door and need to fit a new letterbox, or you’re looking to replace your current one to upgrade the look of your door, this guide will help you confidently tackle the job.
We'll cover the basics of measuring and installing new letterboxes, replacing old letterboxes and troubleshooting some common issues. Let’s get started!
Contents
How to measure your door for a new letterbox
How to measure and replace an existing letterbox
What tools do I need?
- Ruler or tape measure
- Pencil
- Power jigsaw
- Fixing bolts
- Drill
- Narrow chisel and mallet
- Nuts
- Hinge-pin
How to measure your door for a new letterbox
First of all, you have to measure your door for a letterbox. There are plenty of different varieties of letterboxes, so there’s no one-size-fits-all measurement, but it’s a really easy measurement to work out:
Step 1: Measure the height
Start by deciding where you want to install the letterbox. It should ideally be at an easily accessible height.
Measure the height of the centre lock rail (the horizontal section where the letterbox will typically be fitted). Mark the midpoint in two places, approximately 35mm apart.
Step 2: Draw a line
Use a ruler to draw a straight horizontal line between the two marks you made. This line will be the centre of your letterbox position.
Step 3: Find the centre point
Find the centre point of the cross rail by measuring the width, then draw a short vertical line across the previous line. This cross-mark is the exact centre of the letterbox placement.
Step 4: Position the fixing bolts
Position the letterbox so that the centre aligns with the cross-mark on your door. Mark the positions of the fixing bolts on each side of the letterbox. This will ensure that the bolt holes align with your letterbox design so you can properly secure it.
How to fit a new letterbox
Next, you have to create the space to fit your letterbox into. We recommend using a power jigsaw to complete this job - it makes the process much easier!
Step 1: Drill the hole for the fixing bolts
Use the drill to make holes where you marked the fixing bolts. Make sure the holes are big enough for the bolts to slot into but small enough that the bolts have a secure, tight fit.
Step 2: Mark where to cut
Place the letterbox on the door - aligning it with the cross-mark - and trace around the inside edge with a pencil.
The area you trace should be slightly larger than the hinged part of the letterbox so it will open smoothly without catching on the door.
Step 3: Drill holes for the corners
Drill a hole for each corner of the letterbox. Use a drill large enough to create a hole that you can fit the blade of a power jigsaw into to make it easier to cut out the opening with the jigsaw, as they provide entry points for the blade.
Step 4: Cut out the space
Insert the power jigsaw into one of the corner holes and carefully cut along the rectangle to create the opening for your letterbox. Take your time doing this to ensure you get straight lines, which will help create a smoother finish.
Step 5: Cut a space for the hinge pin
If your letterbox has a hinge pin, use a narrow chisel and mallet to create a small recess where the hinge pin will sit. Smooth the edges with sandpaper so the letterbox opens and closes easily.
Step 6: Fix the letterbox
Fit the letterbox into position using the nuts and bolts supplied.
Ensure the letterbox is straight by double-checking with a spirit level before tightening fully.
Step 7: Shorten the bolts if necessary
If the bolts are longer than the thickness of your door - don't worry! You can shorten them with a hacksaw. Just be careful not to damage the door or the letterbox during this step.
How to measure and replace an existing letterbox
If your wooden or UPVC door has an existing letterbox slot, you can simply follow these steps to replace it:
Step 1: Remove the old letterbox
Start by unscrewing and removing the old letterbox. If your screws feel stuck, rusted or difficult to remove, use a lubricant to loosen them first so you don't damage the door or letterbox slot.
Step 2: Measure the existing opening
Use a tape measure to check the width, height, and depth of the existing cutout.
Take measurements in a few spots along the height to ensure accuracy, and note down the smallest measurements to ensure the new letterbox will fit within the opening.
Measure the depth of the cutout (from front to back) to ensure that the new letterbox will not stick out or be too recessed.
Before you buy a replacement letterbox, compare these measurements with the new letterbox dimensions. If your new letterbox is slightly smaller than your existing opening, use filler or caulk to seal any small gaps and prevent drafts or leaks. If your new letterbox is larger, follow the steps above to create a larger opening.
Step 3: Prepare the opening
Your new letterbox might have different fixing points to the old one. Measure the distance between the old fixing points and the new and if needed, fill in any old holes and drill in new ones.
Sand down rough edges, and if there’s any damage, apply filler or caulk to repair it. This step will help ensure a smooth, secure fit for the new letterbox.
Step 4: Fit the letterbox
Use the nuts and bolts supplied with the letterbox to secure it. You can use a spirit level to double-check it’s straight before tightening.
Troubleshooting common issues
Some common issues might arise even if you’re extra careful when installing your letterbox. Here are quick fixes to keep your letterbox in top shape.
- Crooked letterbox: If your letterbox looks crooked, loosen the screws slightly and adjust it before tightening. Use a spirit level to ensure a straight fit.
- Loose letterbox: If your letterbox doesn’t feel secure, add extra screws or fill any gaps with caulk or filler for a tighter fit.
- Weatherproofing problems: If water seeps through, add an extra sealant layer or consider installing a rain cover.
Shop external doors from Leader Online
By following these steps, you can ensure a well-fitted letterbox that enhances your door's function and look.
Shop our external doors and ensure your home makes a great first impression with everything from external wooden doors to exterior doors with glass.
Need more help? Contact our expert product team for more help and advice. We’ll know what size you need and can even discuss pricing and availability with you over the phone.
