Bollom Intulac Ultra Intumescent Clear Basecoat

Bollom Intulac Ultra Intumescent Clear Basecoat is used beneath Intulac Ultra Topcoat where a fire-rated varnish system is required. The specified combination of two basecoats and one topcoat achieves Class B-s1, d0 to BS EN 13501-1:2018. This describes how the complete coating system performs during fire testing:

• B: Limited contribution to the development of a fire
• s1: Low smoke production
• d0: No flaming droplets or particles during the specified test period

Suitability

Suitable for interior hardwood, softwood, plywood, chipboard, hardboard and fibre insulation board within Bollom's specification. The technical data sheet specifies a minimum thickness of 9mm for veneering. Existing varnish must comprise no more than four single coats, all sound and firmly adhered.

Not suitable for surfaces exposed to wear or repeated physical contact, such as doors, floors and stairs.

Complete the System

Finish with the protective topcoat below, available in matt and satin. The stated fire classification depends on using both products at Bollom's specified application rates.

Complete the clear Intulac Ultra system with its matching topcoat, or explore Bollom's opaque coating options below. Alternative systems must be used to their own specified requirements.

Product Use Bollom Intulac Ultra Topcoat The required clear protective topcoat, available in matt or satin, that completes the Intulac Ultra system. Bollom Broflame Ultra Basecoat A white intumescent basecoat for interior wood, used with a specified Flameguard Ultra topcoat when an opaque finish is preferred. Bollom Flameguard Ultra Acrylic Eggshell Topcoat A white eggshell finish for use within the specified Flameguard Ultra system, including over Broflame Ultra Basecoat on wood. Bollom Flameguard Ultra Vinyl Matt Topcoat An opaque matt finish for use within the specified Flameguard Ultra system, including over Broflame Ultra Basecoat on wood.

Prepare bare or previously varnished interior wood thoroughly before applying Bollom Intulac Ultra Intumescent Clear Basecoat. The surface must be clean, dry and sound, with a timber moisture content below 15%.

Older paint coatings, particularly those applied before the 1960s, may contain lead. If these are present, seek advice on safe preparation before sanding or stripping.

1. Remove dust, dirt and any loose surface material
2. Clean away oil, wax, grease and release agents with a suitable cleaner, such as Zinsser Universal Degreaser and Cleaner ensuring no residues remain and allowing the wood to dry fully
3. Check existing varnish for adhesion. No more than four single, sound, firmly adhering coats may remain
4. Scrape loose or flaking varnish back to a firmly adhering surface. If adhesion is uncertain, remove all existing varnish back to bare wood
5. Lightly sand sound existing varnish before coating with Woodleys Flexible Sanding Pads. Thoroughly abrade wood that is difficult to wet so the basecoat can wet the surface evenly
6. Inspect for damaged timber, cracks and holes, and complete any necessary repairs. Confirm compatible fillers and repair materials with Bollom before use
7. For particularly resinous or knotty timber, apply one coat of Zinsser SealCoat as specified by Bollom

Remove all sanding dust and check that the surface is dry and free from contamination before applying the basecoat.

Always apply to a small test area before starting to check compatibility and the final appearance. Follow the manufacturer's instructions on the tin and the current Technical Data Sheet.

The surface temperature must be between 10°C and 40°C and at least 3°C above the dew point. Relative humidity should not exceed 70%. Maintain suitable conditions during application and drying to prevent condensation.

1. Stir thoroughly before use using a Mako Paint Stirrer and apply undiluted
2. Apply by brush, roller or airless spray
3. Apply two coats at 5m² per litre per coat on bare timber, or 4m² per litre per coat on previously varnished timber. Follow these specified rates to achieve the required coating build
4. Allow at least 16 hours between basecoat coats. Lower temperatures and higher humidity may extend drying times
5. If required, lightly sand after the first coat with 150-grit abrasive paper to remove raised wood fibres, then remove the sanding dust before continuing
6. Allow approximately 48 hours after the final basecoat before applying the protective topcoat, and complete topcoating within four days

For airless spraying, use equipment with a pump ratio of at least 30:1, a hose diameter of at least 3/8 inch and a recommended nozzle size of 0.011-0.015 inch (0.28-0.38mm). Use solvent-resistant hoses as specified by Bollom.

Drying times are based on 20°C and 60% relative humidity. Do not stack timber components treated with the Intulac Ultra system.

Bollom Intulac Ultra Intumescent Clear Basecoat must be finished with Bollom Intulac Ultra Topcoat. Apply one coat of the topcoat at 20m² per litre to complete the specified Class B-s1, d0 system. Do not substitute another varnish, as the stated fire classification applies to the complete specified Intulac Ultra system.

How do I get Fire Certification?

Keep your proof of purchase, the batch numbers of the products used and the site details. Submit this information through Bollom's website to request the relevant Certificate of Supply, which Bollom states will be sent within 5 working days.

Can I use the basecoat without a topcoat?

No. Bollom Intulac Ultra Intumescent Clear Basecoat must be finished with Bollom Intulac Ultra Topcoat. The Class B-s1, d0 classification applies to the specified three-coat system, comprising two coats of basecoat and one coat of topcoat.

Can I apply it over existing varnish?

Yes, over a maximum of four single, sound, well-adhered coats of varnish. Remove loose or flaking areas and lightly sand the remaining finish before application. If adhesion is uncertain, remove the existing varnish back to bare wood.

Will the wood grain remain visible?

Yes. The basecoat and its compatible protective topcoat are clear, allowing the wood grain to remain visible. Always complete a small test area first to check the appearance on your chosen timber.

Why are the application rates different for bare and previously varnished wood?

Bollom specifies different coating builds for these surfaces to achieve the stated fire classification. Apply each basecoat coat at 5m² per litre on bare timber or 4m² per litre on previously varnished timber. These are required application rates, rather than maximum coverage estimates.

Can I use it on doors, floors or stairs?

No. Bollom excludes surfaces exposed to mechanical stress, including doors, floors and stairs. The system is intended for suitable interior wood surfaces within the manufacturer's specification.

How long should I wait before applying the topcoat?

Allow approximately 48 hours after the final basecoat and apply Bollom Intulac Ultra Topcoat within a maximum of four days. These timings are based on 20°C and 60% relative humidity; lower temperatures and higher humidity can extend drying times. If these conditions affect the specified overcoating window, seek advice from Bollom before proceeding.