Intumescent Letterboxes

Envirograf Intumescent Letterbox Liner
Price range: £13.83 through £15.06 Select options This product has multiple variants. The options may be chosen on the product page
Envirograf Intumescent Letter Box Unit
Price range: £18.11 through £76.60 Select options This product has multiple variants. The options may be chosen on the product page
10″ Gold Intumescent letterbox ABS Frame / Metal Flap
£12.71 inc. VAT: £15.25 Add to cart
40 x 10″ Gold Intumescent letterbox ABS Frame / Metal Flap DISCOUNT
£487.60 inc. VAT: £585.12 Add to cart
40 x 10″ Silver Intumescent letterbox ABS Frame / Metal Flap SAA DISCOUNT
£443.08 inc. VAT: £531.70 Read more
10″ Silver Intumescent letterbox ABS Frame / Metal Flap SAA
£11.70 inc. VAT: £14.04 Read more

Intumescent Letterboxes

Intumescent Letter Boxes

Intumescent letterboxes are specially designed to improve fire safety and smoke resistance in buildings, providing vital protection for occupants. Suitable for external fire doors in residential and commercial properties, these units are particularly effective in blocks of flats, HMOs, and other multi-occupancy buildings.

With a telescopic design, durable metal flaps, and a high-expansion intumescent sleeve, our letterboxes combine functionality, safety, and style.

How Fire Rated Letterboxes Work

Smoke Protection: In the early stages of a fire, integrated brush seals and frame flaps restrict smoke passage through the letterbox.
Fire Protection: As the fire intensifies, the intumescent sleeve expands, filling the aperture and preventing fire from breaching the door.

This dual action provides tested fire and smoke resistance, maintaining door integrity and enhancing safety.

Sizes Available

Our fire rated letterboxes are available in a range of sizes to suit different applications:

Budget Letterboxes: 300mm x 67mm
- Suitable cut-out: 250mm x 35mm
Variable Letterboxes – Small: 70mm x 315mm
- Suitable cut-out: 50mm x 267mm
Variable Letterboxes – Large: 100mm x 335mm
- Suitable cut-out: 69mm x 290mm

Materials & Finishes

Frame: Black ABS (plastic)
Flaps: Available in aluminium, brass, or steel

Colour options include:

Budget Letterboxes: Black, Chrome, Gold, Satin Chrome, White
Variable Letterboxes: Brown, White, Stainless Steel, Brass

Fire Test Certifications

Our intumescent letter plates are independently tested to meet stringent fire safety standards:

BS476 Part 22:1987 – Maintains door integrity for 61 minutes (composite door test)
EN1634-1:2000 (European Standard) – Provides up to 68 minutes protection

Why Choose Intumescent Letter Boxes?

✔ Certified fire and smoke protection
✔ Suitable for flats, HMOs, and external fire doors
✔ Available in multiple sizes and finishes
✔ Durable construction with modern design

Enhance fire safety without compromising on design. Our intumescent letterboxes are a reliable choice for residential and commercial buildings where compliance and protection are essential.