Thermoguard Thermoproof Interior Fluid

Thermoguard Thermoproof Interior Fluid is a clear, colourless, penetrating Fire Protection

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Thermoguard Thermoproof Interior Fluid is a clear, colourless, penetrating Fire Protection with an optional functional Thermoguard Thermoproof Interior Sealer for wear, damp & UV resistance available in clear or woodstain colours.

Intended Use

Fire protection fluid for porous internal wood.

Finish Options

  • Bare uncoated
  • Clear Sealed
  • Woodstain Sealed

How It Works

In a fire, Thermoproof Fluid reacts with the woods cells to create a flame & heat resistant barrier. Thermoguard Thermoproof Interior Sealer (optional) is a flame-retardant sealer.

Finish Options

  • Bare wood effect
  • Clear sealed - matt or satin
  • Woodstain* - matt or satin

*For available colours see Thermoguard Thermoproof Interior Sealer, also colour match service available.

UKAS Fire Test Standards

  • BS EN Class B s2 dO
  • Class O

Note: This product does not achieve 30 or 60min fire resistance.


  • Bare wood option - 1 coat Thermoguard Thermoproof Interior Fluid


  • Clear sealed finish:

1 coat Thermoproof + 1 coat Thermoguard Thermoproof Interior Sealer Clear**

Woodstain Finish:

1 coat Thermoproof + 1 or 2 coats Thermoguard Thermoproof Interior Sealer Woodstain**

*Resists light cleaning & handling.
**Allow Thermoproof to fully dry (min. 4 days) before applying any sealer.
***2nd coat for added UV protection, damp rooms or moderate cleaning.

NOTE: To check final effect, apply to test patch before application to entire area.


A Certificate of Supply can be issued on request for projects for insurance, Fire and Building Control Authority and Client Records.

Application Methods

Brush, Roller, Spray

Pack Sizes

  • Thermoproof Interior Fluid - 20m², 80m²
  • Clear + Woodstain Sealer - 20m², 80m²

Application Conditions

Apply to dry wood (Max. 16% moisture), above 5°C in dry conditions.

Limitations - Stained, Varnished or Painted Wood

  • For treatment with Thermoproof to be effective, it needs to be able to penetrate the wood.
  • Thermoproof can be applied over water-based penetrating wood dyes that do not seal or make the wood water-proof.
  • To fire protect painted wood, see Thermoguard Timbercoat.
  • To fire protect clear normal varnished wood, use Thermoguard Fire Varnish Basecoat & Thermoguard Fire Varnish Overcoat.
  • To fire protect external stained varnished, woodstained or other coated wood, contact Technical Dept.

New Fire Regulations & Tests Explained

  • The new fire standard BS EN test lasts 20 minutes with airflow replaces the old BS 476 tests which lasted 10 minutes and strangely restricted airflow.
  • The new standard for flamespread and heat release Class B replaces Class O.

The new BS EN tests also monitor -

  • Smoke & Gas “s” – s1 + s2 are none or very low & compliant levels, s3 = moderate , s4 = heavy smoke.
  • Flaming Droplets or Airborne particulates – dO is none, d1 = low, d2 = moderate, d3 = high levels.

Environment & User Friendly

Thermoproof Interior Fluid, Thermoproof Interior Clear & Woodstain Sealers are water-based and environment friendly.

Quality Assurance

Products Manufactured under ISO 9000.