Envirograf Under Floor Fire Barrier
  • Envirograf Under Floor Fire Barrier

Envirograf Under Floor Fire Barrier

Product 53

Use this Under Floor Fire Barrier when ceilings cannot be fireproofed or accessed from below, such as decorated or lath and plaster ceilings.

  • Refer to sizes below
  • Please state if the joist gap differs from 400mm.
  • Provides up to an hour fire protection
  • Optional soundproofing sponge
  • Made from graphite impregnated cloth with foil
VAT excluded

£27.86 Tax incl.



Ref Dimensions Fire Rating
UF60/300 300mm x 1800mm 60 minutes
UF60/350 350mm x 1800mm 60 minutes
UF60/400 400mm x 1800mm 60 minutes
UF60/450 450mm x 1800mm 60 minutes
UF60/500 500mm x 1800mm 60 minutes
UF60/600 600mm x 1800mm 60 minutes
UF104/300 300mm x 1800mm 104 minutes
UF104/350 350mm x 1800mm 104 minutes
UF104/400 400mm x 1800mm 104 minutes
UF104/450 450mm x 1800mm 104 minutes
UF104/500 500mm x 1800mm 104 minutes
UF104/600 600mm x 1800mm 104 minutes

For sound insulation – 40mm thick sound proofing sponge can be ordered:

Ref Dimensions Fire Rating
300/S 300mm x 1800mm 60 minutes
350/S 350mm x 1800mm 60 minutes
400/S 400mm x 1800mm 60 minutes
450/S 450mm x 1800mm 60 minutes
500/S 500mm x 1800mm 60 minutes
600/S 600mm x 1800mm 60 minutes


The underfloor fire barrier is supplied to fit a standard 400mm gap between joists, allowing a further 50mm on each side for fixing.

Please state if the joist gap differs from 400mm.

Skilled tradespeople are required when installing the underfloor fire barrier system.

Although the barrier is extremely durable, care must be taken not to tear the barrier during installation.

All of the supplied metal plates must be used when fixing the barrier in position.

Envirograf's Under Floor Fire Barrier is ideal for ceilings that are hard to access, delicately decorated or made from lath and plaster, fireproofing by installing an underfloor fire barrier from above.

Made from graphite-impregnated cloth with 200g foiled cloth, this fire barrier offers fire protection for up to an hour, slowing down the spread of fire through a building for extra evacuation time. Containing a fire allows more time for emergency services to arrive and extinguish the fire before more damage is caused to a building.

Should you be able to fireproof from below, then Envirograf Fire-Resistant Smooth Finish For Upgrading Plasterboard (Product 105) should suffice.

For additional sound protection, 40mm-thick soundproofing sponge can also be ordered.


1. Lift three floorboards by the wall and three more 2100mm into the room

2. The fire barrier is 1800mm long and its width should be the width between the joists plus 100mm. Each of the long sides should be bent up by 50mm with the grey cloth side up against the joists.

3. Slide the barrier under the floorboards and, where it reaches the wall, bend up the barrier by 50mm.

4. Small metal fixing plates with pre-drilled holes are supplied for fixing the barrier to the joists and the walls. Use one fixing plate at the wall end of the barrier and fasten the barrier to the wall using 30mm galvanised large-head clout nails. Then nail a fixing plate into the joists at intervals of 200mm along each upturned side of the barrier.

5. Re-fix the floorboards you previously lifted beside the wall.

6. Lift three more floorboards, 2100mm away from those already up.

7. Repeat as in step 2 but overlap each new piece onto the previous piece by 50mm and continue like this over the whole floor area.

8. If you have to cut the barrier, self-adhesive-backed Kraft tape is provided to re-seal the cut ends.

9. The barrier can be laid on top of cables. If you need to push a cable or pipe through the barrier then this can be done by making a hole with a screwdriver. Small holes for cables or pipes have no detrimental effect on the barrier as the intumescent material will seal off the holes in a fire. If necessary you can seal puncture holes with Envirograf® Product 58 AM Intumescent Mastic.

Fire Performance:

The underfloor fire barrier, fixed in a typical floor section, was tested in a full-size rig 4m x 3m with a loadbearing capacity of 1.5kN/m² in accordance with BS476 Part 22 (1987) achieving 104 minutes insulation, integrity and load-bearing during test RF95002.

IMPORTANT FIRE PRODUCTS NOTICE: The information displayed on this website should be used as a guide ONLY and our Technical Department should be contacted to obtain a tailored specification and any advice necessary before you place an order for fire protection products. Fire protection products are non-returnable except in accordance with Condition 8 of the Terms and ConditionsWe will not be held liable for any resulting damage to property, human life or monetary costs incurred due to the incorrect specification you have prepared or use of fire protection products caused by your negligence, including your failure to have contacted us to obtain the relevant advice/specification.

Any Envirograf products to be used in or for Harrods department store should be authorised with our Technical Team prior to purchase.

It is your responsibility to read the Product Data Sheets (available below) before you place an order and prior to application of the product. The content of this website is our best recommendation and is not advice. Coverage rates quoted are approximate, you agree that coverage depends on the condition of the substrate, surface absorption, texture and application method. We ALWAYS recommend a trial area is coated to ensure the product meets your requirements before use.

Product Details
Product 53

Customer agrees that before placing an Order, Customer has read and understood the most up to date Product Data Sheet for the Product. Where we have access to the Product Data Sheet from the manufacturer, we will either provide a copy on request, or include a link to the Product Data Sheet available on the manufacturer’s website. Customer further agrees that we have no liability for any errors or omissions contained within the Product Data Sheets. For more information, please see our Terms & Conditions of Sale.

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