Firetherm Intumastic Trowel Grade


We no longer stock this product, but can recommend Nullifire FS721 Trowel Grade Acrylic Sealant as a great alternative.



We no longer stock this product, but can recommend Nullifire FS721 Trowel Grade Acrylic Sealant as a great alternative.

Firetherm Intumastic Trowel Grade coats mineral fibre insulation batts already in-situ, ideal for situations where it is more cost effective to install uncoated mineral fibre batts and slabs, and later apply fire-resistant coatings.

Firetherm Intumastic Trowel Grade coats plain mineral fibre batts of a density exceeding 64 kg/m3, providing up to 4 hours fire integrity to BS 476 Pt 20 and BS EN 1366/3-4, depending on specification. The trowel-grade anti-fire coating contains acrylic emulsion, inert fillers and fungicide, for use on internal applications only.


Compartment walls and floors must maintain the appropriate level of fire resistance as laid down by Building Regulations Section B 2000, in conjunction with a good quality mineral fibre batt system of a minimum density of 140kg/m3


  1. Read Firetherm Intumastic safety data sheet instructions before starting work, in the Attachments tab above.
  2. Carefully check that all mineral is securely positioned and tight, with any gaps over 5mm being filled with offcuts of mineral fibre.
  3. Mask around the opening with masking tape allowing a margin of at least 25 mm to provide a neat well-sealed edge.
  4. Firetherm Intumastic may be applied by spray, brush or trowel. Different specifications of Intumastic can be supplied in order to help you achieve the best results.
  5. Apply to a loading of approximately 1.3 litres per m² to a wet film thickness of 1.3 mm and a dry film thickness of 1 mm.
  6. For bare metal surfaces (such as copper or aluminium), we recommend a barrier tape, masking tape or similar is applied before filling the hole with mastic.
  7. If difficulty is experienced in obtaining adhesion, it is good practice to moisten the mineral fibre before applying the Intumastic with a water sprayer or a paintbrush dipped in water.
  8. Remove masking tape.

Allow Intumastic to dry for at least 24 hours at temperatures higher than 10°C and less than 75% RH before being exposed to moisture. Tack free time: 30 to 120 minutes depending on temperature, humidity and air movement.

Fire Testing

In conjunction with a good quality mineral fibre batt system of a minimum density of 140 kg/m3, Intumastic can provide up to 4 hrs fire integrity to BS 476 Pt 20, BS EN 1366/3-4 depending on specification.

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 Conditions .  We 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.

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

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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