Hardboard HB.H
Grade
ASTM ANSI A135.4 · EN 622-2 · JIS A5905
HB.H = hardboard for humid conditions
Pick when the panel sees intermittent humidity (bathroom/utility interiors, protected exterior soffits).
Values for the HB.H condition
Other Hardboard tempers and conditions
Hardboard is listed in 2 conditions; see the grade overview at Hardboard.
- SERV
- HB.H
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Service | Cheapest grade for non-structural backs, pegboard and packaging where only a smooth face is needed. | — | 12 | 0.9 | — | 0.13 W/m·K |
HB.HThis page Hardboard for humid conditions | Pick when the panel sees intermittent humidity (bathroom/utility interiors, protected exterior soffits). | — | 22 | 1 | — | 0.16 W/m·K |
What is Hardboard HB.H?
Hardboard HB.H is Hardboard in the HB.H grade — pick when the panel sees intermittent humidity (bathroom/utility interiors, protected exterior soffits). Hardboard HB.H has a tensile strength of 22 MPa (3.19 ksi), stronger than 52% of natural material grades. Elongation at break is 1% and the elastic modulus is 4.4 GPa (0.638 Msi). Hardboard HB.H has a density of 0.97 g/cm³ (0.035 lb/in³), heavier than 79% of natural material grades.
Advantages
- Tough — resists crack growth — 0.75 MPa·√m (0.683 ksi·√in), better than 81% of natural material grades
Limitations
- Hard to polish — 25/100, worse than 80% of natural material grades
- Heavy — 0.97 g/cm³ (0.035 lb/in³), worse than 79% of natural material grades
- High embodied carbon — 0.85 kg CO₂/kg, worse than 76% of natural material grades
Hardboard HB.H properties
Typical room-temperature values for Hardboard HB.H; 13 are specific to this condition. Other listed values are Hardboard reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Hardboard HB.H has a density of 0.97 g/cm³ (0.035 lb/in³), heavier than 79% of natural material grades.
Mechanical9
Hardboard HB.H has a tensile strength of 22 MPa (3.19 ksi), stronger than 52% of natural material grades. Elongation at break is 1% and the elastic modulus is 4.4 GPa (0.638 Msi).
Thermal5
Hardboard HB.H is rated for continuous service to 85°C (185 °F). It conducts heat at 0.16 W/m·K (0.0924 BTU/hr·ft·°F), better than 64% of natural material grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical2
Hardboard HB.H is an electrical insulator with a dielectric strength of 2 kV/mm (50.8 V/mil) and a resistivity of 8,000,000 Ω·m.
Chemical & Environmental1
Corrosion resistance is fair (45/100), better than 53% of natural material grades.
Sustainability4
Producing a kilogram of Hardboard HB.H takes about 16 MJ of energy and emits 0.85 kg of CO₂ — more than 79% of natural material grades. Typical recycled content is 85%.
Manufacturability2
Hardboard HB.H's machinability is good (68/100, worse than 74% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Hardboard HB.H
Is Hardboard easy to machine?
Cuts, routs and laser-cuts cleanly with carbide or diamond tooling; the silica-bearing dust is very abrasive, so expect short HSS tool life and use downcut bits plus dust extraction to avoid face chipping.
Can Hardboard be welded?
Not weldable — joined by PVA/urea or hot-melt adhesive, staples, or clinched fasteners into a frame; edge screws split the board.
Can Hardboard be formed, bent or molded?
Can be cold-bent to modest radii in thin gauges (2–4 mm) and formed to tighter radii after water soaking with subsequent drying under restraint; hot pressing during manufacture also allows embossed/perforated (pegboard) profiles.
What surface finishes work on Hardboard?
Smooth S1S face takes primer and paint directly; sand and seal the porous back and all cut edges, since raw edges swell and fuzz — tempered board needs a light scuff sand or a shellac/oil-block primer for good paint adhesion.
Hardboard chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| lignin (self-bonding, part of fibre)fraction of the fibre itself; primary binder in wet-process board | 20 – 30 | 25 |
| phenol-formaldehyde resinadded binder; higher in dry-process and HB.H grades | 0 – 2.5 | 1 |
| paraffin wax / sizingwater repellent | 0.3 – 1.5 | 0.8 |
| drying oil (linseed/tall oil)1–6 % only in tempered grade, polymerised by heat treatment | 0 – 6 | 0 |
| moistureequilibrium MC as shipped | 4 – 9 | 6.5 |
| wood fibre (lignocellulose)steam-refined softwood/hardwood chips or recovered wood | ≥ 92 (balance) | — |
Hardboard HB.H — frequently asked
What is Hardboard HB.H used for?
Hardboard HB.H is typically used for cabinet backs, door skins, laminate flooring core, pegboard and packaging. In short: densest engineered wood panel; smooth paint-ready face; thin-gauge cold-bendable skin.
What is the tensile strength of Hardboard HB.H?
Hardboard HB.H has a typical tensile strength of 22 MPa (3.19 ksi) — stronger than 52% of natural material grades. Strength varies by condition: see the 2 listed tempers.
Is Hardboard HB.H easy to machine?
Reasonably — machinability is rated good (68/100, worse than 74% of natural material grades). Cuts, routs and laser-cuts cleanly with carbide or diamond tooling; the silica-bearing dust is very abrasive, so expect short HSS tool life and use downcut bits plus dust extraction to avoid face chipping.
Can Hardboard HB.H be welded?
Not weldable — joined by PVA/urea or hot-melt adhesive, staples, or clinched fasteners into a frame; edge screws split the board.
What surface finishes work on Hardboard HB.H?
Smooth S1S face takes primer and paint directly; sand and seal the porous back and all cut edges, since raw edges swell and fuzz — tempered board needs a light scuff sand or a shellac/oil-block primer for good paint adhesion.
Can Hardboard HB.H be formed, bent or molded?
Can be cold-bent to modest radii in thin gauges (2–4 mm) and formed to tighter radii after water soaking with subsequent drying under restraint; hot pressing during manufacture also allows embossed/perforated (pegboard) profiles.
What is the maximum service temperature of Hardboard HB.H?
Hardboard HB.H is rated for continuous use to about 85°C (185 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 622-2 Fibreboards — Specifications — Requirements for hardboards — CEN (2004)
- ANSI A135.4 Basic Hardboard — Composite Panel Association / ANSI (2012)
- JIS A 5905 Fibreboards — JISC (2014)
- Wood Handbook — Wood as an Engineering Material, Ch. 11 Wood-Based Composite Materials — USDA Forest Products Laboratory (2021)
- Inventory of Carbon & Energy (ICE) v3 — fibreboard/hardboard — Circular Ecology (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.