How to Measure and Install Your UPVC Letterbox: A Comprehensive Guide

Upgrading or replacing a UPVC letterbox can enhance the appearance and functionality of your door. Whether it’s due to wear and tear, a broken flap, or simply for aesthetic reasons, installing a new letterbox is a straightforward process when done correctly. In this guide, we’ll walk you through the steps to measure and install Your UPVC letterbox, along with tips, tools, and best practices. By following these instructions, you’ll have a perfectly fitted letterbox ready to welcome your daily mail.

Why Choose a UPVC Letterbox?

UPVC (Unplasticised Polyvinyl Chloride) letterboxes are an excellent choice for homeowners due to their impressive durability, cost-effectiveness, and ease of maintenance. Designed to resist harsh weather conditions and rusting, they are built to last for years with minimal upkeep. The material’s smooth surface also makes cleaning simple, requiring just a damp cloth to maintain its appearance.

One of the greatest advantages of UPVC letterboxes is their versatility. They come in a wide array of styles, colours, and sizes such as the 10″ Letterbox (40-80mm) and 12″ Letterbox (40-80mm) allowing homeowners to select an option that perfectly complements the aesthetic of their property.

For those seeking enhanced security, options like the Mila SuperSecure Letterplates provide anti-snap and anti-fishing features, making them an excellent choice for safeguarding your mail. Whether you’re updating an old letterbox or installing one for the first time, UPVC offers a practical, stylish, and reliable solution.

Before You Begin: What You’ll Need

Tools & Materials:

• Measuring tape (preferably metric)
• Screwdriver (flathead and Phillips)
• Pencil or marker
• Replacement UPVC letterbox
• A soft cloth for cleaning
• Optional: A small hacksaw or file (if adjustments are needed)

Ensure you purchase a letterbox specifically designed for UPVC doors. Most UK homeowners prefer to buy from trusted suppliers like NE Lock & Key to guarantee durability and weather resistance.

Step-by-Step Guide to Measuring Your Existing Letterbox

Accurate measurements are key to selecting the right letterbox for your door. Follow these steps to ensure precision.

Measure the External Dimensions: Begin by measuring the current letterbox’s overall external dimensions—height, width, and the centre distance between the mounting screw holes. Take care to get precise measurements to avoid gaps or fitting issues.

Check the Aperture (Opening) Size: Next, measure the actual hole cut into your UPVC door. This aperture size is crucial. Measure both the width and height of the internal opening. Since UPVC doors differ in thickness, it’s essential to find a letterbox that can accommodate your door’s depth.

Door Thickness: If you’re unsure about the door’s thickness, open the door and measure from the interior to the exterior face. Confirm that your chosen letterbox model can handle this thickness. Many UPVC letterboxes are adjustable to fit a range of door depths, typically between 40-80mm.

Note Any Irregularities: UPVC doors can sometimes have contours or mouldings around the letterbox area. Make sure to note these details, as you’ll need to ensure the replacement fits flush.

Write all measurements down carefully. Having accurate numbers makes it easier to find a suitable replacement.

Choosing the Right UPVC Letterbox

When selecting a new letterbox, keep these factors in mind:

• Material: Opt for a durable UPVC or aluminium flap for added strength.
• Weather Resistance: Ensure the letterbox includes a draught seal or brush to prevent wind and rain from entering your home.
• Design: Choose a style and colour that complements your door. Products like the Arrone Letterboxes offer a combination of functionality and aesthetic appeal.
• Security Features: Look for anti-snap and anti-fishing designs to protect your mail.

How to Install Your New UPVC Letterbox

Once you have the correct letterbox and the required tools follow these steps for a hassle-free installation:

Remove the Old Letter Box

• Unscrew the external and internal plates of the existing letterbox.
• Gently push out the old letterbox from the aperture.
• Clean the area to remove dirt and adhesive residue.
• If it’s stuck, gently wiggle it free—avoid using excessive force.

Insert the New Letterbox

• First, insert the external part of the letterbox through the aperture from the outside.
• Align it carefully so that the mounting holes match the internal side of the frame.

Secure the Letterbox

• Position the internal frame from inside the door
• Screw the internal and external plates together, ensuring they’re tightly secured but not over-tightened.
• Check that the flap opens and closes smoothly.

Seal the Edges (Optional)

• Apply a thin line of silicone sealant around the edges of the letterbox to prevent draughts and water ingress.
• Wipe away any excess sealant with a soft cloth.

Common Mistakes to Avoid

Even a straightforward DIY task like replacing a letterbox can go wrong if you’re not careful. Here are some common mistakes to avoid:

Incorrect Measurements: One of the most frequent mistakes is purchasing a letterbox that doesn’t fit. Always double-check your measurements, including aperture size, external dimensions, and door thickness.

Choosing the Wrong Type of Letterbox: Not all letterboxes are compatible with UPVC doors. Ensure you buy a model specifically designed for UPVC.

Over-Tightening Screws: Tightening screws too much can crack or distort the UPVC material. Tighten them just enough to secure the letterbox without overdoing it.

Ignoring Weatherproof Features: Skipping on integrated brushes or seals might save a few pounds initially, but it can lead to draughts, water ingress, and higher energy bills in the long run.

Not Cleaning the Aperture: Failing to clean the aperture before installation can leave debris that interferes with the proper fit of the letterbox.

Misaligning the Letterbox: Misaligned screws or frames can cause the flap to jam or make the letterbox look uneven. Always align both the internal and external parts carefully.

Measuring and installing a UPVC letterbox is a straightforward process that anyone can handle with a bit of preparation. By following the steps outlined above, you’ll ensure a perfect fit and long-lasting performance for your new letterbox. Always double-check measurements and invest in a high-quality product to make the upgrade worthwhile.

Explore our range of high-quality letterboxes, including the Mila Slim Master UPVC 12″ Letter Box for slim designs and the Arrone 12″ Letter Box for classic options. With our products tailored to most of your doors, you’re sure to find a letterbox that meets your needs and style preferences. Happy DIYing!

FAQ About UPVC Letterboxes

How do I know if a letterbox will fit my UPVC door?

Measure the aperture size, external plate dimensions, and door thickness before purchasing a letterbox. Most manufacturers provide detailed size guides to help you choose.

What is the standard size of a UPVC letterbox in the UK?

There’s no single “standard” size as UPVC doors and letterboxes vary. Common widths range from about 250mm to 300mm. Always measure your door’s aperture before purchasing to ensure the best fit.

How often should I replace my UPVC letterbox?

A high-quality UPVC letterbox can last several years with proper maintenance. Replace it when it becomes damaged, doesn’t close properly, allows draughts, or no longer complements the look of your door.

What are anti-fishing letterboxes?

Anti-fishing letterboxes include a security feature that prevents thieves from retrieving mail using tools or hands. They’re ideal for added home security.

Can I replace my UPVC letterbox myself, or should I hire a professional?

Many homeowners can manage the replacement themselves with basic DIY skills and tools. If you’re unsure or encounter issues (like a non-standard aperture size), consider hiring a professional installer.