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Intumescent Liner for Letter Box

Product 50


Intumescent liners for improving the fire rating of existing letter box apertures.

Not available to purchase online.

We need to ask you a few more questions and ensure this is the suitable product for your needs.

To order please call us on +44 (0) 1 304 842 555

£0.00 ex. Vat


Intumescent Liner for Letter Box

An intumescent liner for letter box. This product comprises of two adhesive L-shaped sections with self-adhesive backing for fixing. Seal any bare wood apertures with paint or wood sealer before fixing the liner, this will ensure optimum efficiency.

  • For mail apertures in fire doors where letter flaps already exist.
  • Aperture sizes up to the limit for each type (LBL1 and LBL2) adjust the liners by cutting with a sharp knife as required.
  • Suitable for fitting to doors from 38mm to 70mm thick.

See the order references tab for all standard sizes that are available. Sizes to suit other openings are available to order.

These products were included in a fire test employing the general procedures and criteria of BS476 Part 22 (1987) built into a composite door, maintaining the integrity of the door for 61 minutes. Also tested to European Standard EN1634-1 (2000), achieving 68 minutes.

If you are looking for a letter box unit in addition to the letter box liner, take a look at the Intumescent Letter Box Unit Range online here.

Our products upgrade doors to Fire Door rating, in compliance with Building Control. Browse our full range of Fire Door products and Fire Door Accessories online


– Provides up to 68 minutes protection- Can be custom made to suit a range of aperture sizes
– Suitable for fitting to doors from 38mm to 70mm thick
– Liner can be easily cut to size to fit the opening

Application Instructions

The product is supplied in 4 pieces, 2 long lengths for the top and bottom, and 2 shorter lengths for each side of the letterbox opening. Each small section is attached to the large section using DST (double sided tape).
Place the long sections on top of the side sections to form an L-shape liner, and cut the ends to the required size to suit the opening. Peel of the DST (double sided tape) and adhere to the inside of the letterbox opening. Use panel pins supplied to secure both side sections to the letterbox opening.

Order References / Sizes

LBL1    (85 x 340mm)

LBL2   (65 x 290mm)

LBL3   (39 x 254mm)