This is a common practice that creates a continuous, airtight, and watertight barrier.
Why is sealant needed?
In this system, sealant serves three main purposes:
Waterproofing and Sealing: This is the key function. A good sealant keeps rain and snowmelt out of the building. It blocks moisture from entering through the board joints. This keeps wall insulation safe. It also protects the wood or metal frame from moisture, mold, and corrosion.
Airtightness: Sealant fills small gaps, reducing air leaks. This improves energy efficiency, lowering heating and cooling costs.
Coping with Structural Displacement: Buildings face thermal expansion and contraction. A good elastic sealant expands and contracts as joints change width. This keeps the seal intact and stops cracks in the board from stress.
How to Apply Seal in the Right Way?
If you choose this system, we specialize the sealant application.
Choose a quality sealant. Only use a silicone or polyurethane sealant that's designed for outdoor use that will withstand weather, UV light, and bond to fiber cement boards. Cheap and/or interior sealants will crack and fail.
Use backing strips: Insert circular closed-cell foam strips into joints before sealing. They control sealant thickness and shape, ensuring even stretching and compression. They also prevent three-sided adhesion, allowing the sealant to bond only to the board's sides.
Stay Clean Surfaces: Utilize a professional cleaner to thoroughly clean all dirt and debris away from the surfaces of the joint. This removes release agents, oil and dust to increase health of bond with sealant.
Application: Great for applications that have to have strong airtightness and watertightness. Particularly for adverse weather conditions that encounter a lot of rain, snow, wind or temperature shifts.
Option 2: Open Joint System – No Seal Required
This modern approach is popular in commercial and contemporary residential buildings. It focuses on "drainage and ventilation."
Why is sealant unnecessary?
In this design, we leave the joints open. The idea is not to block water but to promote drainage.
Drainage and Ventilation: The design lets small amounts of water flow out through joints or cavities. Ventilation helps moisture evaporate, keeping walls dry-a smarter waterproofing strategy.
Releasing Aesthetic Tension: Open joints form shadow lines and give a three-dimensional look. This creates a clean, modern appearance for buildings. This prevents defects and discoloration from aging sealant. It keeps façades looking uniform over time.
Eliminating Maintenance Concerns: Without sealant, you won't need regular inspections or resealing as it ages.
How does the system ensure waterproofing?
No sealant doesn't mean no waterproofing. Workers install a specialized waterproof and breathable membrane behind the fiber cement board. This membrane lets moisture out but stops liquid water from getting in. The board and seams act as the first line of defense and drainage channels.
Suitable Scenarios: Great for modern minimalist or industrial designs. Best in dry climates or places with little rain. Perfect for projects aimed at cutting long-term maintenance costs.