If plastering hollows, cracks, pattern-like cracks and inspection confirms that they are hollow cracks, you should first remove the mortar layer in the hollow area and clean the base layer. Clean the dust and water and moisten it before plastering. ; When there is no clear water on the base wall, apply plain cement slurry, apply the bottom layer of ash, and then apply the top layer of ash after the mortar has initially set; the thickness of the plastering layer at one time should not exceed 5-8mm to reduce the drying shrinkage rate; strictly follow the coordination Than prepared mortar. After the mortar is plastered and solidified, the whitening construction can be carried out. First, cut off the whitening surface of the old wall at the new and old joints of the wall plaster with a width of 120. After cleaning, use a 160-wide glass fiber mesh or non-woven fabric at the new and old joints. Paste 801 glue and cement on the old and new joints, that is, mix 801 glue and cement into a paste, paste non-woven fabric or fiberglass mesh cloth on the wall with a width of 80 on each side, and then scrape the large white surface after it dries. layer.