When it comes to selecting a product to seal cement board joints, standard thinset mortar is not the ideal choice. Traditional thinset mortar is designed to adhere tiles to a substrate but lacks the necessary flexibility and waterproofing properties required for joint sealing. Thinset mortar is typically not recommended for filling joints due to its composition, which may result in cracking or separation as the building materials expand and contract over time.
Alternatives for Cement Board Joint Sealing
To ensure a proper seal for your cement board joints, it is best to use specialized products designed explicitly for this purpose. There are various options available in the market, including cement board joint tape and cement board joint compound. These products are specifically formulated to provide flexibility, water resistance, and durability, making them suitable for sealing cement board joints.
Cement Board Joint Tape:
Cement board joint tape is a self-adhesive mesh tape that reinforces cement board joints. It helps prevent cracks from forming in the joints by providing extra reinforcement. This tape should be applied over the joints before applying the joint compound.
Cement Board Joint Compound:
Cement board joint compound is a flexible and waterproof material that is specifically designed for filling and smoothing cement board joints. It adheres well to the cement board surface and ensures a tight and stable joint seal. This joint compound can be applied using specialized tools, such as a joint knife or trowel.Standard thinset mortar is not suitable for sealing cement board joints. While it is an excellent choice for securing tiles to cement board, it lacks the flexibility and waterproofing properties required for joint sealing. To achieve proper and durable joint sealing, it is essential to use specialized products, such as cement board joint tape and cement board joint compound. By doing so, you can ensure the longevity and integrity of your cement board installation while preventing water damage and maintaining tile stability.