We've seen pink plasterboard, paints, and rough plasters. But construction often has uncompromising demands.
What if we need to clad a steel column in a semi-outdoor garage where it rains and humidity is extreme? Pink plasterboard will absorb water, rot and disintegrate. What about a motorway tunnel where a tanker fire will reach 1,200°C in 5 minutes, and we want to hose down the space with high-pressure jets afterwards? Paints and plasters might delaminate. This is where the "Special Forces" of dry construction come in.
Dry construction (building with screws and boards) is fast and clean. However, when conditions become hostile, gypsum (even the fire-rated kind) shows its weaknesses. It can't withstand continuous impacts and, most importantly, it hates water. For heavy industrial, outdoor or underground applications, engineers turn to Calcium Silicate Boards. Their chemical composition (sand, cement/lime and reinforcing cellulose or glass fibres) is "baked" in special high-pressure autoclaves. The result: the ease of a board with the resilience of stone. Visually, they resemble hard, off-white cement boards. They have no external paper layer and are extremely dense.
These panels aren't for building a simple partition in your living room - they're considerably more expensive and heavier than plasterboard. They are designed for where everything else fails.
Unlike pink plasterboard that relies on evaporating water (and then crumbles), calcium silicate is inorganic. There is nothing to burn, no vapours released, no shrinkage. A double layer of these panels around a steel column can provide fire resistance of up to 240 minutes (4 full hours) even in extreme hydrocarbon fire conditions (as found in refineries)!
This is their greatest "weapon." You can install them in a basement car park that floods, a semi-outdoor canopy or inside a tunnel. Even when completely soaked, they don't rot, don't mould and don't lose their mechanical strength. When they dry out, they return to exactly their original condition.
If you hit plasterboard with a supermarket shopping trolley, it punches right through. If you hit a calcium silicate board, the trolley probably breaks. They are ideal for hospital corridors, forklift warehouses and industrial areas where the wall "takes a beating" every single day.
Calcium silicate panels are used in three main categories:
When we want square, smooth, attractive columns (unlike the rough spray plaster) but in spaces with moisture or the risk of mechanical impacts.
The massive metal ducts that extract smoke from basements must withstand fire so they don't melt. They are clad externally (or built entirely) from calcium silicate panels to maintain integrity.
Tunnel ceiling linings are made of these panels, so that if a vehicle catches fire inside, the concrete of the tunnel structure doesn't collapse from temperatures of 1,200°C.
Pink plasterboard rots in rain, crumbles on impact and maxes out at 120 minutes. Calcium silicate resists water, impacts and reaches 240 minutes. Plasterboard is ideal for interior spaces, while calcium silicate excels in extreme outdoor and industrial applications.
We've built a closed, semi-outdoor parking in our yard with heavy steel columns. In winter, humidity is extreme and rain constantly soaks the structure.
The contractor "clad" the columns with pink plasterboard to give them fire resistance and painted them. After two winters, rainwater soaked the bottom section of the plasterboard completely. The material rotted and crumbled. In year 3, our car catches fire. The columns are effectively bare at the base. The steel melts and the canopy collapses onto the burning vehicle.
The engineer demanded the columns be clad with calcium silicate panels. Rain, snow, standing water at the base - the panels couldn't care less. The car bursts into flames. The panels face 1,000°C as if it were a simple… "warm-up." After the fire is extinguished, we hose down the panels with water. The steel underneath is completely pristine!
Final Takeaway: When conditions get "warlike," we leave gypsum for living rooms and reach for calcium silicate. It's the ultimate, heavy-duty, non-combustible board that ensures your fire protection won't dissolve… in the first rain!
Return to category.
Go to categoryReturn to the central guide.
Go to guide
