You are here:

Fire mortar

Product 6


Intumescent fire mortar to provide a load-bearing fire seal in floors and walls

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


An asbestos-free dry mix to which water is added and then mixed like plaster. When set, the mortar is load bearing. It can be drilled with wood bits to allow the installation of services. Used in conjunction with either product 4 or 5, the mortar provides a permanent fire stopping solution for load bearing floors, walls and ceilings.


– Great for fire-stopping around building services that pass through floors

– Can be used on fire rated timber, plasterboard, concrete
walls and brick, block or concrete floors
– Acts as permanent shuttering around services, filling apertures in walls and floors
– The following fire ratings can be achieved with the corresponding thickness:
– Up to 6-hour protection: 100mm
– 4-hour protection: 25mm
– 3-hour protection: 12mm
– 2-hour protection: 6mm
– 1-hour protection: 3mm
IMPORTANT – This product is for use with intumescent slabs (Products 4 or 5) and must not be used by itself

Application Instructions

For the 25 kg bag, add 4 ¼ to 4 ¾ litres of water, and mix like plaster. For floors,
pour into the floor opening. For walls, apply over a Rockwool Slab with a trowel or
float. 25 kg bag will fill approx. 8600 cm³ or 2 bags will fill 0.83 m² to depth of 25 mm.

Application into floor: For openings 600 mm x 900 mm, no wire mesh is required. Just
fit Rockwool slab, fit Envirograf Protection around any services and fill over the Rockwool
to the required depth, with the FM Fire Mortar. For larger openings, fit 50 mm RW4 or
RW6 Slab where large areas over 1 metre wide, use Envirograf® Ref: SUP Support
Bars (As Picture) under Rockwool. Fit 30 mm wire mesh over the Rockwool, cutting
around services and wiring to the services. Fix wire mesh all around the perimeter of
the hole, bend up the wall or floor and fit with Envirograf® FB/C Metal Battens to
support the mesh.
Fit Envirograf® Fire Protection Wraps around pipes and electrical services,
Intumescent Pads inside and Trunking Pillows for Cable Trays. Product 40 Fire Proof
Sponge around ventilation trunking. Then mix FM Fire Mortar and pour into the
opening to the required depth.

Order References / Sizes


FM25                      25 kg regular fire mortar GREY-coloured

FM05/A                  25 kg plus 6.25 kg aggregate additive = 31.25 kg total dry mix GREY-coloured



FM25/P                  25 kg PINK-coloured fire mortar

FM25/AP               25 kg plus 6.25 kg aggregate additive = 31.25 kg total dry mix PINK-coloured


SUP                        Metal Support Batten for large floor openings (see illustration top of page), price per metre

MESH                    30mm wire mesh x 1200mm width, sold per linear metre run