Tile Backer Board  is a lightweight, waterproof high-density XPS foam tile backer board that replaces heavy, moisture-prone cement boards with a cleaner, faster, and more reliable solution. It creates a strong, durable, waterproof, and mold-resistant surface for showers, bathrooms, and wet areas — saving installers time and effort while ensuring lasting protection.

Superior Moisture Resistance – Closed-cell XPS core prevents leaks, rot, and microbial growth.

Installer-Friendly – Cuts with a knife — no dust, no power tools, no mess.

Rigid & Load-Bearing – Supports large-format tile and heavy stone.

Up to 70% lighter than cement board for effortless transport and installation. Reduce fatigue and speed up every job.

Long Term Performance - Will not warp, deform, or rot over time.

100% Waterproof – Inherently waterproof XPS foam tile backer board with effective vapor resistance. Protects walls, floors, and subfloors from water damage, leaks, and mold.

）Closed-Cell Integrity – Maintains full waterproof performance even if the outer surface is cut or punctured. Unlike open-cell materials, it will not absorb or wick moisture.

Mold & Mildew Resistant – Non-organic composition prevents microbial and fungal growth for long-term durability and a cleaner, healthier installation.

Long Term Durability – PROVA-Board will not warp, swell, or deteriorate over time—preventing tile cracks and grout failures for a long-lasting, beautiful tile install.

Thermal Insulation - XPS foam core delivers excellent insulating value, ideal for saunas, or residential steam rooms (requires installation in conjunction with PROVA Mat).

A comprehensive introduction to roof waterproof backing board

1、 Overview of roof waterproof backing board

Roof waterproof backing board is an indispensable and important component of modern building waterproofing systems. As a base support material for waterproofing membranes or coatings, it plays a key role in roof waterproofing engineering. The backing board is usually installed between the roof structure layer and the waterproof layer, providing a flat and sturdy base for the waterproof material, effectively dispersing loads, preventing the waterproof layer from being pierced, and possessing certain insulation, heat insulation, and moisture resistance functions.

With the continuous development of building technology and the increasing demand for building quality, roof waterproof backing boards have evolved from traditional single function to composite materials that integrate multiple functions such as waterproofing, insulation, sound insulation, and fire prevention. In various types of building roofing projects, especially in large public buildings, industrial plants, and residential projects, the application of waterproof backing boards is becoming increasingly widespread.

2、 The main types of roof waterproof backing boards

1. Extruded polystyrene (XPS) backing board

XPS backing board is a widely used waterproof backing material in the current market. It is mainly made of polystyrene resin and extruded through a special process, with a closed cell honeycomb structure. The significant features of XPS board are high strength, low water absorption, and excellent insulation performance. Its compressive strength can reach 150-700kPa, water absorption rate is less than 1%, and thermal conductivity is between 0.028-0.032W/(m · K), making it very suitable for roof waterproofing systems with high load requirements.

2. Expanded polystyrene (EPS) backing board

EPS backing board is made by heating and pre foaming expandable polystyrene beads, and then heating and molding them in a mold. Compared with XPS board, EPS board has a lower density (usually 15-30kg/m ³) and relatively lower compressive strength (about 50-150kPa), but it is more economical in price. The thermal conductivity of EPS board is about 0.035-0.040W/(m · K), and the water absorption rate is between 2-4%. Due to its light weight and good processing performance, EPS board is often used in roof waterproofing projects with low load requirements.

3. Polyurethane (PU) backing board

The polyurethane backing board is a rigid foam plastic board made of polyurethane as the main raw material through chemical reaction foaming. PU board has an extremely low thermal conductivity (0.020-0.025W/(m · K)) and is currently one of the backing boards with good insulation performance. Its compressive strength can reach 150-300kPa, and its water absorption rate is less than 3%. In addition, PU board also has good fire resistance, and some products can reach the B1 level flame retardant standard. However, due to its high price, PU backing boards are often used in high-end buildings or projects that require particularly strict insulation performance.

4. Composite backing plate

Composite backing plate is a new type of backing material made by compounding different materials through special processes. Common composite forms include XPS and waterproofing membrane composite, EPS and metal foil composite, PU and gypsum board composite, etc. The composite backing board combines the advantages of various constituent materials, such as XPS and waterproof membrane composite board, which not only has the high strength and insulation performance of XPS, but also has the waterproof function of waterproof membrane, greatly simplifying the construction process. This type of product represents the development direction of backing board technology.

3、 Technical performance indicators of roof waterproof backing board

High quality roof waterproof backing board should meet the following key performance indicators:

1. Physical and mechanical properties: including density, compressive strength, flexural strength, dimensional stability, etc. For example, the compressive strength of XPS backing board used for accessible roofs should not be less than 250kPa.

2. Thermal performance: mainly reflected in thermal conductivity and thermal resistance values. The lower the thermal conductivity, the better the insulation performance. The thermal conductivity of XPS board is usually around 0.030W/(m · K).

3. Waterproof and moisture-proof performance: Water absorption rate and moisture permeability coefficient are important indicators. The water absorption rate of high-quality XPS board can be controlled below 1%, and it is almost impermeable to moisture.

4. Durability: including anti-aging performance, freeze-thaw cycle resistance, etc. The service life of the specially treated backing plate can exceed 25 years.

5. Fire resistance: According to the GB8624 standard, the combustion performance of building materials is divided into four levels: A (non combustible), B1 (flame retardant), B2 (combustible), and B3 (flammable). The roof backing board should reach at least B2 level.

6. Environmental performance: It should comply with relevant national environmental standards, not contain harmful substances, and some high-end products also have recyclability.

4、 Construction points of roof waterproof backing board

The correct construction method is the key to ensuring better performance of the backing board:

1. Grassroots treatment: Before construction, ensure that the roof base is flat, dry, and free of debris. The moisture content of concrete base should not exceed 8%, and that of wooden base should not exceed 12%. Uneven areas need to be leveled with cement mortar, and cracks should be repaired in advance.

2. Board laying: The backing board should be laid with staggered joints, and the joints should be sealed with special tape. XPS boards are recommended to be arranged in an "I" shape, with seam width controlled within 5mm. Roofs with a slope greater than 15% should be equipped with anti slip measures.

3. Fixing method: Choose the appropriate fixing method according to the type of roof. Concrete roofs can be fixed using adhesive or mechanical methods; It is recommended to use specialized screws to fix wooden roofs, with no less than 4 fixing points per square meter.

4. Joint treatment: The joints between boards should be filled with polyurethane foam adhesive and covered with waterproof tape on the surface. The connections with parapets, skylights, and other parts should be reinforced.

5. Waterproof layer construction: When laying a waterproof layer on the backing board, it should be ensured that the two are compatible. SBS modified asphalt waterproofing membrane can be directly hot-melt pasted on XPS board; Polymer waterproofing membranes need to be coated with specialized adhesives first.

6. Protective measures: During the construction process, heavy objects should be avoided from hitting the backing board. After completion, a protective layer should be promptly covered to prevent direct sunlight and rainwater immersion.

5、 Application advantages of roof waterproof backing board

Compared with traditional roof waterproofing structures, the waterproofing system using professional backing boards has multiple advantages:

1. Improve waterproof reliability: The backing plate provides uniform support for the waterproof layer, reducing damage to the waterproof layer caused by base cracking. According to statistics, the leakage rate of roofs using backing boards is reduced by more than 70% compared to traditional methods.

2. Extend service life: The backing plate can effectively buffer temperature stress and prevent premature aging of the waterproof layer. Actual engineering cases show that the service life of roof waterproofing systems using XPS backing boards can reach 2-3 times that of conventional methods.

3. Simplify the construction process: The composite backing board integrates multiple functions such as waterproofing and insulation, reducing construction layers and shortening the construction period by about 30%. Especially during winter construction, the backing board is not affected by low temperatures to ensure project progress.

4. Reduce overall costs: Although the initial investment in the backing board is relatively high, considering the reduced maintenance costs and extended service life, the investment cost can be recovered within 5-8 years, and the long-term economic benefits are significant.

5. Enhance building performance: High quality backing boards not only provide waterproofing, but also improve the building's insulation, sound insulation, noise reduction, and overall energy efficiency and comfort.

6、 The development trend of roof waterproof backing board

With the development of the construction industry towards greenization and industrialization, the technology of roof waterproof backing board has also shown a new trend of development:

1. Multi functional integration: In the future, backing boards will pay more attention to multi-functional integration, such as waterproof thermal insulation fireproof integration, waterproof sound insulation structural integration, and other products will be more favored by the market.

2. Environmental sustainability: Environmentally friendly backing boards made from renewable and biodegradable materials will gradually replace traditional products. Some companies have started developing backing boards based on biobased polyurethane.

3. Intelligent application: The intelligent backing board embedded with sensors can monitor the status of the roof waterproofing system in real time, warn potential problems in advance, and achieve preventive maintenance.

4. Standardized construction: With the promotion of prefabricated buildings, prefabricated and standardized backing plate systems will greatly improve construction efficiency and quality controllability.

5. Performance customization: Tailored backing panels for different climate regions and building types will become mainstream to meet personalized needs.

In short, as an important component of modern building waterproofing systems, the technology and application of roof waterproof backing boards are still constantly developing and innovating. The correct selection and use of backing plates are of great significance for ensuring the quality of roof waterproofing engineering and extending the service life of buildings. Construction practitioners should closely monitor industry trends, master new technologies and product information, and choose suitable backing solutions for engineering projects.