Letterbox rattling, flap sticking, spring broken or finish faded? A new 12 inch letterbox is a quick upgrade for a composite, uPVC or timber front door. We stock heavy-duty 12 inch letterboxes and letterbox sets from Fab & Fix (including Heritage), Avocet Affinity and Affinity Ultra stainless steel, greenteQ Omega and Coastline stainless steel, Mila ProStyle, Trojan Unicorn, Yale (Welseal, Slim Master and Postmaster), Ultion Sweet and ERA.
12 inch is the most common letterbox size on composite and uPVC doors. Match the plate size, bolt centres and door thickness of your old letterbox so it fits the existing holes.
Measure the width and height of the old letterbox plate on the outside of the door. The new plate should cover the same area so no old marks show.
Measure between the centres of the fixing bolts. Matching them lets you reuse the existing holes.
Measure the opening cut through the door. The new letterbox must cover it fully.
Check the thickness of your door against the range on the listing. Composite doors are often thicker than uPVC doors.
Composite doors are usually thicker than uPVC doors, so choose a letterbox set that suits your door thickness. Many of our heavy-duty sets, such as the Fab & Fix, Ultion Sweet and ERA sets, are made for composite, uPVC and timber doors.
From inside, undo the fixing bolts or screws and remove the inner and outer parts of the old letterbox. Clean the door around the opening, fit the new outer plate, push the bolts through, fit the inside part and tighten evenly. Check the flap opens and closes freely before you finish.
About 12 inches across the outer plate. Exact plate, slot and bolt sizes vary by model, so check the listing against your old letterbox.
Yes, if the plate covers your existing opening and the set suits your door thickness. Many of our sets are made for composite doors.
Usually, yes. Most letterboxes bolt through the door, so a like-for-like swap only needs a screwdriver.
Fit an internal letter box cover with a brush or flap on the inside of the door.
Browse all letter boxes: 12 inch letterboxes, 10 inch letterboxes, letter box covers and post box accessories.
Not sure which letterbox fits your door? Send us a photo of your old letterbox with a tape measure alongside and we'll match it for you.
Send us a photo to identify your partMonday to Friday, 8:30–12:30 and 13:00–15:30
