Cement board · PermaBASE
PermaBASE Cement Board
A rigid backer board made of Portland cement, aggregate and glass mesh. It won't rot, swell or fall apart when wet, so it's the go-to substrate behind tile, stone veneer and stucco, inside and out.
- Moisture and mould resistant (ASTM D3273 score of 10, the best possible)
- EdgeTech reinforced edges let you fasten close to the edge without crumbling
- Scores and snaps with a utility knife
- Class A fire rating, flame spread 0
- UL GREENGUARD Gold certified for low emissions
Size 1/2" × 3' × 5'
In stock at our Langley showroom, 5837 Production Way.
About PermaBASE cement board
PermaBASE is a cement backer board with an exceptionally hard surface that stands up to prolonged moisture. Use it as the underlayment for tub and shower surrounds, countertops and floors, and as the substrate for cement board stucco and adhered stone veneer walls.
On exteriors, PermaBASE replaces the traditional metal lath and scratch coat behind manufactured or natural stone, thin brick and tile. It's faster, cleaner and more consistent, and it makes it easy to add continuous insulation to the wall.
Sizes we stock
| Size | 1/2" × 36" × 5' (12.7 × 914 × 1,524 mm) and 1/2" × 48" × 8' (12.7 × 1,219 × 2,438 mm) |
|---|---|
| Coverage | 15 sq. ft. per 3' × 5' board, 32 sq. ft. per 4' × 8' board |
| Weight | 2.9 lb per sq. ft. nominal, about 44 lb per 3' × 5' board and 93 lb per 4' × 8' board |
| Pieces per unit | 50 boards (3' × 5'), 30 boards (4' × 8') |
Need another thickness or size? PermaBASE also makes 3/8", 5/8" and 3/4" boards. Ask us about special orders.
Where to use it
- Showers and tub surrounds A tile backer that won't rot or swell, for showers, tubs, steam rooms and saunas.
- Floors and countertops A stable underlayment for tile floors, kitchen counters and backsplashes.
- Fireplaces and heat shields UL approved as a heat shield (ANSI/UL 1618, ULC S632), reducing required clearance from the wall by 40%.
- Stone and brick veneer The Cement Board Masonry Veneer system (CBMV) for manufactured stone, natural stone and thin brick, cited for ASTM C1780.
- Cement board stucco The Cement Board Stucco System (CBSS), an engineered alternative to traditional three-coat stucco.
- Outdoor kitchens and decks A durable exterior substrate where tile or stone will see weather.
Specifications
| Composition | Portland cement, aggregate and glass mesh, EdgeTech reinforced edges |
|---|---|
| Standard | ASTM C1325, IBC/IRC compliant |
| Flexural strength | ≥ 750 psi |
| Compressive strength | 1,250 psi |
| Fastener holding | ≥ 90 lb (wet and dry) |
| Water absorption | < 8% of weight (24-hour immersion) |
| Freeze/thaw | > 100 cycles |
| Wind load | 40 psf (studs 16" o.c.) |
| Mould resistance | Score of 10 (ASTM D3273), score of 0 (ASTM G21) |
| Fire | Class A, flame spread 0, smoke developed 0 (ASTM E84). 1/2" board is UL classified for 1- and 2-hour rated assemblies. |
| Thermal resistance | R-0.37 (1/2") |
| Bending radius | 5' |
Values for 1/2" board from the PermaBASE submittal sheet.
Installation basics
- Framing Studs at 16" o.c. maximum for interior walls, designed to L/360 deflection.
- Fasteners PermaBASE cement board screws or galvanized roofing nails every 8" o.c., 3/4" into wood or 3/8" into steel framing.
- Joints Alkali-resistant mesh tape set in modified mortar. Never paper tape or joint compound.
- Cutting Score on the printed side with a utility knife and snap.
- Exterior walls Install over primary sheathing and a water-resistive barrier, following the CBMV or CBSS system.
- Control joints Every 30 lineal feet maximum inside. Outside, follow the finish manufacturer, or 16 feet maximum.
Always follow the PermaBASE construction guide and your local building code.
Installation videos
Warranty
PermaBASE carries a lifetime limited warranty for residential interior use, 30 years for commercial interiors and 15 years for exterior applications. Ask us for full warranty terms for your project.
Technical documents
- Submittal sheet
- Construction guide
- 3-part guide spec
- Safety data sheet
- UL code report ERR22158
- GREENGUARD Gold certificate
- Exterior warranty (15-year)
- Interior warranty (lifetime)
- Commercial interior warranty (30-year)
Documents open on the PermaBASE and National Gypsum websites. See all our documents on the Resources page.
Need cement board for your project?
Tell us what you're building and we'll quote boards, screws and tape.
