The application of external wall insulation and heat-insulating mortar in building energy efficiency.

According to the national industry standard "Energy-saving Design Standard for Residential Buildings in Hot Summer and Cold Winter Areas" (TGJ134-2001): Residential buildings achieve a 50% energy-saving goal by enhancing the thermal insulation performance of the building envelope and improving the energy efficiency ratio of heating and air conditioning equipment. This requires considering energy-saving measures for every part of the house, with the most important being to strengthen the insulation performance of the envelope structure. Plastering insulation mortar is one of the economical, convenient, and quick construction methods.

1. Project Example

Yancheng Yuehu Huacheng Residential Community is a high-end residential area mainly composed of small high-rise buildings, with a total construction area of over 250,000 square meters, a frame shear wall structure, one basement level, and sixteen above-ground levels. The wall insulation system design is as follows: a exterior wall coating, b crack-resistant and anti-seepage mortar 4mm, c alkali-resistant glass fiber mesh, d crack-resistant and anti-seepage mortar 4mm, e polystyrene particle insulation slurry 25mm (35mm for the north facade), f interface agent, g base wall. The RE composite wall insulation material is easy to use; it only needs to be mixed with water and can be used directly without adding any additives or auxiliary materials. It has good thermal conductivity, high compressive and shear strength, and low linear shrinkage. After the materials arrive on site, witness sampling tests are conducted, and the test results are: compressive strength 0.9Mpa, thermal conductivity (25℃) 0.068W/(m2.k), loose density 391kg/m3, and the test results meet the requirements. After use, the surface mortar shows few cracks, and the energy-saving effect of the external wall insulation is significant.

2. Product Performance

(1) RE (Rare Earth) Composite Wall Insulation Material Series (Mortar) is a new type of fiber-reinforced wall material made from fly ash and composite silicate as the binding material, with ultra-light polystyrene foam particles as the lightweight aggregate, and various additives added, using a unique new technology to form a single-component product. The RE (Rare Earth) Composite Wall Insulation Material Series (Mortar) should be protected from rain and moisture during transportation and storage, and its shelf life should not exceed 45 days from the date of manufacture. The main performance indicators of the adhesive powder polystyrene particle insulation slurry are: thermal conductivity ≤0.060W/m2.k, compressive strength ≥200Kpa, softening coefficient ≤0.3%, linear shrinkage rate ≥0.5.

(2) RE-type crack-resistant and anti-seepage agent is a non-toxic, odorless, and pollution-free environmentally friendly plaster mortar additive, appearing as a gray fibrous powder. Its main components are economical water-soluble polymers and high-strength fibers. The random distribution of high-strength fibers in the mortar body helps prevent the generation and development of micro-cracks, enhancing the toughness of the mortar, thereby reducing the occurrence of cracks and hollowing in the plaster layer. The main performance indicators of the crack-resistant and anti-seepage agent are: usable time ≥1.5h, tensile bond strength ≥0.7Mpa, compressive ratio ≤3.0.

(3) Alkali-resistant glass fiber mesh has the characteristics of corrosion resistance and high tensile strength, effectively controlling wall shrinkage cracks and anti-cracking functions. Taking the ordinary type as an example, the performance indicators of the alkali-resistant glass fiber mesh are: mesh center distance 4×4mm, unit area weight ≥160g/m2, breaking strength (warp, weft) ≥1250N/50mm, breaking elongation ≤5%, coating amount ≥20g/m2.

3. Construction Process and Control Points

The construction process must comply with the Ministry of Construction's mandatory industry standards "Polystyrene Particle External Wall Insulation System" (JG158-2004) and the "Construction Drawings for External Wall Insulation" issued by the Jiangsu Provincial Construction Department. A sample should be made according to the construction process for comprehensive evaluation, and large-scale construction can only begin after certification meets the requirements. In addition to providing detailed technical disclosures, material suppliers should also strengthen on-site guidance on product performance.

(1) Construction Process Flow

Base treatment → Apply interface treatment agent → Make gray cakes → Apply the first layer of insulation mortar, curing → Apply the second layer of insulation mortar, curing → Apply anti-seepage and crack-resistant mortar and install nylon expansion bolts (for six stories and above) → Apply surface anti-seepage and crack-resistant mortar → Curing → Acceptance.

(2) Base Wall Treatment

The wall surface must be cleaned thoroughly to ensure it is free of oil, dust, and other contaminants that hinder bonding, and protrusions on the wall surface should be removed. If the thickness of the insulation mortar exceeds design requirements, rough treatment should be performed first.

(3) Apply Interface Treatment Agent

The interface treatment agent should be applied evenly to prevent missed spots. The interface agent is mixed in a ratio of interface agent: medium fine sand: cement = 1:1:1 (weight ratio). First, add 1 part interface agent, then add 1 part medium fine sand and cement, and mix into a slurry to apply evenly with a roller.