High-Temperature Insulation Boards

Understanding High-Temperature Insulation Board Types

High-temperature insulation boards differ substantially in material composition, density, thermal conductivity, rigidity, temperature capability and intended position within an installation. A board designed to construct a fireplace enclosure performs a different role from a vermiculite stove lining, a low-mass ceramic fibre furnace board or a fireboard intended to receive a heat-resistant decorative finish.

VITCAS manufactures and supplies several board technologies for domestic heating, specialist construction and industrial thermal processing. Correct selection starts with the function the board must perform, followed by temperature, insulation thickness, mechanical exposure, fixing method and the conditions on both the hot and cold sides of the installation.

Fireplace Construction Board

VITCAS Fireplace Construction Board is a rigid calcium silicate insulation board designed for constructing fireplace chambers, false chimney breasts, tiled stoves and enclosures around compatible inset and cassette appliances. Its rigid format allows accurately formed fireplace structures while providing thermal insulation around the heating installation.

The board is rated up to 1000°C and is offered in 1000 × 610 × 30 mm and 500 × 610 × 30 mm formats. It provides the mechanical stability required for its specified fireplace-construction system, but it should not be treated as a general load-bearing building board or structural masonry component.

Vermiculite Fireboards

VITCAS Vermiculite Fireboards are lightweight rigid insulation boards rated up to 1100°C. They can be cut and shaped for heat shields, register plates, stove chamber linings, range cookers and other compatible heating applications.

Plain vermiculite board can also be used as a replacement panel in suitable stoves where the appliance design, dimensions and board specification match the original component. Decorative reeded and brick-effect versions provide the same type of lightweight board format with a patterned visible surface for suitable fireplace and stove installations.

Vermiculite boards are primarily intended for indoor or adequately protected installations. Their ease of machining does not remove the need to verify board thickness, fixing arrangement, appliance compatibility and exposure conditions.

Ceramic Fibre Insulation Boards

VITCAS ceramic fibre boards are rigid, vacuum-formed insulation products with a density of 300 kg/m³. Compared with flexible ceramic fibre blanket, the rigid board form maintains a defined profile and provides greater resistance to gas flow while retaining low thermal mass and low thermal conductivity.

Ceramic Fibre Board 1260°C is suited to applications including ceramic and glass kilns, forge insulation, heat-treatment furnaces, boiler ducts, stacks and compatible industrial lining systems.

Ceramic Fibre Board 1430°C extends the temperature capability for more demanding applications such as higher-temperature ceramic kilns, glass slumping and fusing, furnaces, afterburners and process equipment.

Both grades are supplied as 1200 × 1000 mm boards with 25 mm and 50 mm thickness options. Selection between 1260°C and 1430°C grades should be based on the temperature and operating conditions at the board position rather than choosing the higher classification without reference to the complete lining design.

Bio-Soluble Fibre Board 1300°C

VITCAS Bio-Soluble Fibre Board 1300°C is a rigid high-temperature insulation board manufactured from low-biopersistence bio-soluble fibres. With a density of 300 kg/m³, it combines low thermal conductivity and low heat storage with the dimensional stability of a rigid board.

The 1300°C board provides an alternative fibre technology for suitable furnace and kiln linings, heat-treatment equipment, boiler systems, refractory backup insulation and refurbishment work. Its installation position, thickness, retention method and mechanical exposure should be assessed as part of the complete refractory or insulation system.

HT High-Temperature Fireboard

VITCAS HT High-Temperature Fireboard is a rigid, non-gypsum board rated up to 650°C. It measures 1200 × 800 × 12 mm and is classified A1 for reaction to fire in accordance with EN 13501-1:2019.

HT Fireboard is particularly suited to compatible heat-resistant finishing systems, including surfaces that will receive heat-resistant plaster, tiles or paint. Applications also include suitable boiler areas and specified wall, ceiling, door and barrier constructions.

Its role differs from Fireplace Construction Board and vermiculite stove-lining boards. HT Fireboard should not automatically be selected as a direct stove heat shield or supporting fireplace enclosure simply because it is non-combustible and temperature resistant.

High-Temperature Insulation Board Selection Guide

Board type	Material	Maximum listed temperature	Format	Typical duties
Fireplace Construction Board	Calcium silicate	1000°C	1000 × 610 × 30 mm or 500 × 610 × 30 mm	Fireplace chambers, false chimney breasts, tiled stoves and suitable inset or cassette appliance enclosures
Vermiculite Fireboard	Vermiculite	1100°C	Rigid boards in selected dimensions	Heat shields, register plates, stove linings, replacement panels and suitable hobby-kiln applications
Decorative Vermiculite Fireboards	Vermiculite	1100°C	Reeded or brick-effect surfaces	Visible fireplace and stove linings, heat shields and suitable replacement panels
Ceramic Fibre Board 1260°C	Vacuum-formed ceramic fibre, 300 kg/m³	1260°C	1200 × 1000 mm; 25 or 50 mm thick	Kilns, forges, heat-treatment furnaces, boiler ducts, stacks and industrial insulation
Bio-Soluble Fibre Board 1300°C	Bio-soluble fibre, 300 kg/m³	1300°C	1200 × 1000 mm rigid board	Furnaces, kilns, heat-treatment equipment, boilers and refractory backup insulation
Ceramic Fibre Board 1430°C	Vacuum-formed ceramic fibre, 300 kg/m³	1430°C	1200 × 1000 mm; 25 or 50 mm thick	Higher-temperature kilns, glass processing, furnaces, afterburners and process equipment
HT High-Temperature Fireboard	Rigid non-gypsum fireboard	650°C	1200 × 800 × 12 mm	Heat-resistant finishing, tile backing, boiler areas and specified wall or ceiling systems

Maximum temperature is only one part of insulation-board selection. The required board type and thickness depend on the complete assembly, including hot-face temperature, thermal conductivity, cold-face requirements, joints, fixings, adjacent materials and environmental exposure.

Where High-Temperature Insulation Boards Are Used

Different VITCAS board technologies serve different parts of domestic, commercial and industrial thermal systems.

• Fireplaces, stoves and commercial heating: fireplace chambers, stove surrounds, false chimney breasts, register plates, range cookers, heat shields and suitable replacement panels.
• Ceramic and glass processing: kiln linings, kiln doors and baffles, glass slumping, fusing and other controlled high-temperature processes.
• Furnaces, forging and heat treatment: rigid lining zones, backup insulation, forge insulation and low-mass thermal barriers.
• Boilers, power and process equipment: ducts, stacks, boiler systems, furnaces and associated high-temperature insulation.
• Incineration and high-temperature exhaust systems: suitable insulation zones in incinerators, afterburners and related process equipment.
• Heat-resistant and fire-rated construction: specified finishing boards, wall, ceiling, door and barrier systems where the complete construction provides the required documented performance.

How to Select the Correct Insulation Board

1. Define the board's function: establish whether it will form a fireplace enclosure, act as a heat shield, line thermal equipment, provide backup insulation, replace a compatible stove panel or receive a decorative finish.
2. Determine the temperature at the board position: consider normal operation, local hot spots and the temperature reaching each layer rather than using appliance or furnace temperature alone.
3. Compare thermal performance and thickness: assess thermal conductivity at the relevant mean temperature, available space, layer arrangement and required cold-face temperature.
4. Assess mechanical exposure: consider gas velocity, vibration, abrasion, repeated handling and the need for the board to maintain a defined profile or support a finishing system.
5. Check the environment: confirm suitability for direct flame, combustion gases, moisture, process atmosphere and any chemical or physical exposure relevant to the installation.
6. Use the appropriate fixing or retention system: depending on the board, this may involve mechanical fixings, compatible board adhesives or an engineered industrial retention arrangement.
7. Confirm the complete system: appliance clearances, adjacent combustible materials, joints, penetrations, finishes and any regulated fire-performance requirement must be considered together with the board itself.

Temperature Rating, Conductivity & Board Thickness

A board's maximum listed temperature indicates the thermal class or service capability specified for that product. It does not determine the insulation thickness required or predict the temperature on the opposite side of the assembly.

Thermal conductivity generally changes with temperature, so insulation calculations should use conductivity data appropriate to the relevant operating or mean temperature. Two boards with similar maximum temperature ratings may have different densities, conductivity values and thermal-storage characteristics.

Increasing the thickness of the same insulation material will normally reduce heat transfer, but joints, fixings, penetrations and thermal bridges can materially affect the performance of the completed construction.

Rigid Fibre Boards vs Dense Refractory Linings

Ceramic and bio-soluble fibre boards provide low-density, low-thermal-mass insulation. This can reduce stored heat and support faster heating and cooling compared with dense refractory constructions.

They should not, however, be assumed to replace dense refractory materials in every hot-face position. Areas exposed to significant abrasion, impact, molten materials, aggressive process chemistry or severe mechanical wear may require a different refractory material or a protected multi-layer lining.

Rigid fibre boards can also require suitable support or retention. Their rigidity helps maintain an insulation profile, but it does not make them equivalent to load-bearing refractory masonry.

Installation, Cutting & Handling

Measure and cut insulation boards accurately to minimise unnecessary gaps and thermal bridges. Cutting methods differ by material: rigid calcium silicate and vermiculite products can be worked with appropriate conventional tools, while ceramic fibre boards can be trimmed using suitable fibre-board cutting methods.

Follow the product safety data and use appropriate dust control, ventilation and protective equipment during cutting and handling.

Use the fixing or retention method specified for the selected board and installation. Fireplace boards may use compatible mechanical fixings and board-system adhesives, while industrial fibre boards can require different supporting or retention arrangements.

Store boards dry and protect edges and surfaces from unnecessary damage. Fibre boards in particular should be handled carefully to preserve their dimensions and minimise uncontrolled fibre release.

Fire Classification Is Different from Temperature Resistance

A maximum temperature rating and a reaction-to-fire classification describe different properties.

For example, HT High-Temperature Fireboard is rated to 650°C and has an A1 reaction-to-fire classification under EN 13501-1:2019. A1 indicates that the classified material is non-combustible within the scope of that classification; it does not by itself provide a stated period of fire resistance for a completed wall, ceiling, door or barrier.

Where a project requires a particular fire-resistance period or classification, the complete tested or documented assembly must be considered, including board layers, supporting construction, joints, fixings, penetrations and exposure direction.

Frequently Asked Questions

What are high-temperature insulation boards used for?

They provide rigid thermal insulation, heat shielding, board-based lining or heat-resistant construction in applications including fireplaces, stoves, kilns, furnaces, forges, boilers, ducts, stacks and industrial process equipment. The correct board depends on the particular thermal and mechanical duty.

Which board should I use to construct a fireplace enclosure?

VITCAS Fireplace Construction Board is specifically designed for constructing compatible fireplace chambers, false chimney breasts, tiled stoves and enclosures around suitable inset or cassette appliances. Appliance clearances and the complete board installation system must still be observed.

Which board can replace a panel inside a stove?

Vermiculite fireboard may be suitable where the appliance manufacturer permits replacement with this type of board and the material, thickness and dimensions match the required component. Ceramic fibre board should not automatically be substituted for a domestic stove panel simply because it has a higher temperature rating.

What is the difference between 1260°C and 1430°C ceramic fibre board?

Both are rigid vacuum-formed ceramic fibre insulation boards with a density of 300 kg/m³ and low thermal mass. The 1430°C grade provides a higher temperature capability for more demanding applications. Selection should be based on the actual lining temperature and process environment.

What is Bio-Soluble Fibre Board 1300°C?

It is a rigid high-temperature insulation board manufactured from low-biopersistence bio-soluble fibres. It provides low thermal conductivity and low heat storage for suitable furnaces, kilns, boiler systems, heat-treatment equipment and refractory backup insulation.

Does a thicker insulation board provide better thermal insulation?

Increasing the thickness of the same material generally reduces heat transfer. Actual performance also depends on conductivity at temperature, density, joints, fixings, thermal bridges and the other layers in the complete construction.

Can high-temperature insulation boards be cut to size?

Yes. The appropriate cutting method depends on the material. Calcium silicate and vermiculite boards can be worked using suitable tools, while ceramic and bio-soluble fibre boards require cutting methods appropriate to fibre insulation products. Use suitable dust control and protective equipment.

Can insulation boards be plastered, tiled or painted?

Selected boards can receive compatible finishes when correctly prepared. HT Fireboard and Fireplace Construction Board are used within specified finishing systems, while the preparation required for vermiculite or other boards depends on the individual product and installation.

Does an A1 board automatically provide a fire-resistance period?

No. A1 is a reaction-to-fire classification for the material. A fire-resistance period applies to a complete tested or otherwise documented construction incorporating the specified boards, supporting structure, layers, fixings and joints.

Can a temperature-rated insulation board be installed directly against combustible material?

Not on the basis of its temperature rating alone. The board's hot-face and cold-face temperatures, thickness, ventilation or air gap, appliance clearances and complete construction must all be verified before reducing separation from combustible materials.

Can ceramic fibre boards be exposed to high-velocity gases?

Rigid ceramic fibre boards provide greater resistance to gas flow than flexible ceramic fibre blanket, but suitability still depends on gas velocity, erosion risk, process atmosphere, board support and whether additional surface protection is required.