How to choose between cement based and gypsum based self-leveling underlayment

Gypsum-based self-leveling suitable for thick layer leveling Secondly, self-leveling gypsum can be constructed mechanically, and it can be cast and formed in one go without the need for later moisturizing, sprinkling, and curing. It usually takes 4-6 hours for people to install it, and the next process can be carried out after 3-7 days depending on the actual environmental conditions.

 

In the field of decoration, self-leveling materials have gradually become the first choice for ground treatment due to their unique advantages-easy construction, accurate leveling, rapid drying and the ability to significantly shorten the construction period.

However, faced with the two mainstream choices of gypsum-based self-leveling and cement-based self-leveling, consumers are often faced with a difficult choice. Today, we will talk about floor heating and the difference between these two.

It is not difficult to see from the name that gypsum-based self-leveling and cement-based self-leveling are different raw materials. Gypsum-based self-leveling is mainly composed of gypsum, aggregates and polymer additives. The type and proportion of gypsum Different ingredients are also divided into different categories, which we will talk about later.

Cement-based self-leveling is composed of cement, cementitious materials, and a variety of modified additives. It relies on Portland cement as the foundation, integrating high-performance cementitious materials and a variety of modified additives to achieve higher strength and durability. The difference in basic materials between the two determines their different performance characteristics.

Performance comparison

Gypsum itself is more stable in nature and is not greatly affected by thermal expansion and contraction. The dimensional change rate is -0.05% to +0.05%. When used in floor leveling, it has good volume stability and can effectively solve the problems caused by thermal expansion and contraction of cement mortar. Cracked and hollow. However, because gypsum easily softens when exposed to water, its characteristic is that it cannot be used in places that are often in contact with water.

Cement-based self-leveling cracks due to improper maintenance

Relatively speaking, cement-based self-leveling can be used in places that require waterproofing. However, the shrinkage rate of cement-based self-leveling is much higher than that of gypsum-based self-leveling, ranging from -0.15% to +0.15%. And as time goes by, the shrinkage value of cement-based self-leveling will increase, so it may cause The cracking of self-leveling mortar requires special attention to maintenance.

 

Thermal conductivity comparison

There is a significant difference in thermal conductivity between gypsum-based self-leveling and cement-based self-leveling. In contrast, the thermal conductivity of cement-based self-leveling is usually between 0.6 and 1W/(m·k). The specific value is affected by the material ratio and preparation process. The thermal conductivity of ordinary gypsum-based self-leveling is usually 0.528W/(m·k). The small thermal conductivity indicates that the material has a weak ability to conduct heat, which is beneficial to maintaining indoor temperature stability and reducing energy waste.

However, when applied to floor heating backfill, the larger the thermal conductivity, the more conducive it is to the heat transfer into the room. At present, there are high thermal conductivity gypsum-based self-leveling products with added thermal conductive materials, and their thermal conductivity can reach 1±0.05W/(m·k). Considering the dimensional stability in the floor heating environment and the reduction of indoor floor height, users who install floor heating recommend high thermal conductivity gypsum-based self-leveling when choosing self-leveling products.

Construction comparison

Both require interface agent and boundary leakage prevention, defoaming and other treatments, but generally speaking, the single construction thickness of gypsum-based self-leveling is larger and is suitable for working conditions with large ground errors, while cement self-leveling is only suitable for thin Layer leveling.

 

Gypsum-based self-leveling suitable for thick layer leveling

Secondly, self-leveling gypsum can be constructed mechanically, and it can be cast and formed in one go without the need for later moisturizing, sprinkling, and curing. It usually takes 4-6 hours for people to install it, and the next process can be carried out after 3-7 days depending on the actual environmental conditions. The final setting and drying time of self-leveling cement is relatively long, and the finished product requires about 14 days of curing, resulting in a longer construction period.

 

Summarize

How to choose self-leveling depends on the construction site and construction needs: 1. If the site is often in contact with water, such as kitchens, bathrooms, etc., or areas where ceramic tiles are required as floor decoration surfaces, use cement-based self-leveling; 2. If If you need to protect pipes under the ground, and the protection needs to be at least 1cm beyond the highest point of the pipe, use gypsum-based self-leveling; 3. For users who lay floor heating pipes and later use the floor as the ground decoration layer, it is recommended to use high thermal conductivity gypsum with thermal conductive materials added 4. Whether you choose gypsum-based self-leveling or cement-based self-leveling, you need to check the environmental protection test report to ensure that the decoration materials meet environmental protection requirements.