Thermoguard Thermoproof Interior is a clear, colourless, penetrating fire protection fluid designed for bare, porous internal timber. It creates a heat and flame-resistant barrier when exposed to fire, helping to meet UK building and fire regulations. Optional Thermoguard Interior Sealer is available in clear or woodstain finish for added durability and UV resistance.

Surface Preparation

• Apply only to bare or porous timber.

• Ensure the timber is dry (≤16% moisture) and free of coatings, sealers, or finishes that prevent absorption.

• Can be used over water-based penetrating wood dyes that do not make the surface waterproof.

• Always test on a small patch before full application.

Technical Data

• Fire Rating: BS EN Class B s2 d0 & Class 0

• Finish Options:

  • Natural bare wood

  • Clear matt/satin (with optional sealer)

  • Woodstain colour (with optional sealer)

• Drying Time (before sealing): 4+ days

• Pack Sizes: 20m² and 80m²

• Application Methods: Brush, Roller, or Spray

• Environmental: Water-based, low VOC, ISO 9000 manufacture

• Not suitable for painted, varnished, or sealed timber – use Timbercoat or Fire Varnish system instead

Directions for Use

1. Apply 1 coat of Thermoproof Interior Fluid to clean, porous wood.

2. Allow to dry fully for at least 4 days in good conditions.

3. Optional: Apply 1–2 coats of Thermoguard Interior Sealer (clear or woodstain) depending on wear resistance and UV protection required.

4. Maintain application temperature above 5°C. Ensure good ventilation during drying.

5. Apply by brush, roller, or spray. Clean tools with water.

Data Sheets

Thermoguard Thermaproof Interior - TDS

Thermoguard Thermaproof Interior - MSDS