Aerogel coatings have quickly gained popularity in exterior wall energy-saving renovations due to their astonishingly thin and excellent insulation properties. Here, we'll lay out the standard practices and hidden key points all at once, retaining the process, data, and cases but presenting them in a more concise manner. 
Step 1 to 4, in sequence, cannot be messed up. 
Entry preparation 
Wall inspection: First, examine the condition of the base layer, then calculate the energy-saving indicators, and determine the combination of "primer + intermediate coat + topcoat" and the total thickness. 
• Material Preparation: The main material of aerogel must contain nano-scale aerogel powder; standard equipment includes high-pressure airless spray guns, mixers, and protective films. 
The "Four Requirements" for the base layer - firm, level, clean and dry. 
Knock off hollow areas and old layers that have peeled off, and wash away all oil stains and moss. 
Cracks and holes are filled with matching mortar and then the surface is sanded as a whole to achieve the required flatness. 
Work can commence only when the moisture content is qualified, the weather forecast indicates no rain, the temperature is below 35℃, and the humidity is below 85%. 
The coating is "one primer, two intermediate coats and one topcoat" (for high-end projects, it can be "one primer, two intermediate coats and two topcoats"). 
① Primer: Apply one coat by spray or roller. Allow to dry for at least 4 hours. It is only for adhering to the wall. 
② Intermediate coat: The aerogel insulation layer must be applied in two layers, each 1 mm thick, with an interval of at least 6 hours; sufficient time should be allowed for the three-dimensional network to set, so that the insulation performance remains true. 
③ Topcoat: One coat of high-reflective heat insulation topcoat, which serves as both a "sunscreen" and a cosmetic layer, with a total dry film thickness of 2–2.5 mm after application. 
Acceptance + Maintenance and Warranty 
After each process is completed, a ruler is used to measure, visual inspection is conducted, and wet film/dry film spot checks are carried out. Only when the results are qualified can the next process be entered. 
Upon completion, non-destructive thickness gauges shall be randomly inspected. At least 3 points per 100 m² shall be inspected. The average thickness shall be no less than the design value, and the minimum value shall be no less than 90% of the design value. 
One year after delivery, a review should be conducted. If there is dirt, it can be rinsed with clean water. For any damaged areas, simply apply the same system of paint directly for repair. 
Why Be So Sentimental? 
• Thin = Strong: 2 mm replaces several centimeters of traditional insulation boards, reducing the load on exterior walls and eliminating the fear of detachment during old building renovations. 
A 6-hour interval is a hard and fast rule: if you spray too thickly in one go, the solvent won't be able to escape, and later on, it will shrink and crack, causing the insulation performance to plummet directly. 
• System compatibility: primer adhesion, intermediate coating insulation, and topcoat reflection. If any one of these steps is missing, all thermal data will be invalid. 
III. Practical Performance Record 
In the old renovation community in Yangquan, Shanxi Province, the indoor temperature in winter has increased by 3℃, the temperature of the exterior walls in summer has dropped by 18℃, and the air conditioner setting of the residents has been raised by 2℃. 
A primary school in Shanghai: After renovation, the maximum drop in the surface temperature of the exterior walls was 18℃, and the annual air conditioning energy consumption was reduced by 40%. 
In the police station in Xiangtan, Hunan Province, when the air conditioning temperature was raised under the condition of the same level of comfort, electricity consumption was reduced by about 40%. 
Four. The Most Common Pitfalls to Avoid 
Personnel: Wear masks and goggles when spraying, keep the area well-ventilated, and don't let the aerogel powder act as "baby powder". 
Thickness: Don't blindly believe in "one-time film formation". For 2 mm, it must be done in two applications. Wet film thickness should be spot-checked on-site at any time. 
Design: Insulation is prioritized in the north, while reflection is emphasized in the south. The thickness and type of topcoat should be calculated by the design institute; don't make decisions based on intuition. 
Team: Find a professional team that has worked on aerogel projects. There are specific requirements for equipment pressure, nozzle diameter, and gun movement speed. Unprofessional teams cannot produce qualified thermal engineering data.