Envirograf Intumescent Letterbox Liner

Availability: In Stock


An intumescent letter box liner comprising two adhesive L-shaped sections which are fitted into existing mail apertures.

Used for improving the fire rating of existing letter box apertures.

We can also supply new intumescent letterplates. Please click here to order.

Envirograf Intumescent Letterbox Liner

The Envirograf Intumescent Letterbox Liner is designed to upgrade existing letterbox openings or flaps in fire doors, to make them fire rated.

They are easy to fix as they come in two L-shaped sections backed in double-sided tape. This can be cut if necessary, ensuring appropriate sizing to fit the opening. Please use a sharp knife for cutting.

Please contact us if none of the standard sizes are appropriate, so we can provide a bespoke quotation.

Ensure any bare wood openings are sealed with paint or wood sealer before fixing.

These letterplate liners are suitable for doors between 38mm and 70mm thick.

Fire testing:

Tested to BS476 Part 22 1987, built into a composite door, maintaining the integrity of the door for 61 minutes.

Tested to European Standard EN1634-1 (2000), achieving 68 minutes protection.

For further technical information, please refer to the technical data sheet in the data sheets tab above.

Application Instructions:

Place the long L-section on the side section, then cut both angles to length.

Peeling off the double sided adhesive, stick the letterbox to the inside of the opening.

We advise to insert panel pins into both side pieces.

For an application instructions print-out, please refer to the application instructions in the data sheets tab above.


Order References:

LBL1 (85 x 340mm).

LBL2 (65 x 290mm).


We can also supply new intumescent letterplates. Please click here to order.


For technical support, please call us on 01752 690997.


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Data Sheets