Do I need to reserve expansion joints for the leveling of ceramic tile backer boards?

　　Do I need to reserve expansion joints for the leveling of ceramic tile backer boards? Whether expansion joints need to be set during the leveling of bathroom walls with ceramic tile backer boards depends mainly on the specific construction conditions and design requirements. Here are some key considerations:

　　1. Design Specifications

　　According to the "Roofing Engineering Construction Quality Acceptance Specification GB50207-2002", the leveling layer should be equipped with dividing joints, and the width of the dividing joints should not be less than 20mm and the spacing should not be greater than 6m. These specifications are designed to ensure the effectiveness and durability of the waterproof layer.

　　2. Building structure

　　If there are structural cracks or uneven settlement in the bathroom wall, it may cause damage to the waterproof layer. Therefore, when designing and construction, it is necessary to consider how to deal with these potential structural issues.

　　3. Waterproof material

　　Different waterproof materials have different sensitivity to temperature changes. For example, SBS waterproof coils are flexible materials that are less sensitive to thermal expansion and contraction, and may not require expansion joints.

　　4. Protection layer

　　If a protective layer, such as cement mortar or fine stone concrete, it is very important to set up expansion joints in the protective layer to prevent the protective layer from cracking due to temperature changes.

　　5. Geographical location and climatic conditions

　　Specific geographical locations and climatic conditions, such as cold winters in the northern region, may cause structural shrinkage, so expansion joints need to be set up to accommodate this climate change.

　　To sum up, whether the expansion joints need to be installed on the ceramic tile backer board should be decided based on the actual situation of the project and the requirements of the design documents. If set up, construction should be carried out strictly in accordance with the requirements of the specifications and design drawings to ensure project quality and safety of use.