The invention discloses a construction method for grouting reconstruction repairing of an existing waterproof layer. By referring to related
engineering data, the position of the waterproof layer andthe scope to be repaired of a building are determined, and then setting out, hole arrangement and grouting are performed. A traditional
reconstruction method is changed, the
construction waste disposal and roofing repairing processes are reduced, grouting holes are arranged in a plum-blossom shape to enable the effective coverage area to be larger, and the cost is saved. Accumulated water betweenthe holes is discharged through the
pressure difference between the holes which is formed by row-by-row and hole-by-hole grouting, the discharged water is replaced and supplemented by
grout, and a small amount of undischarged water participates in the solidification reaction of the
grout, so that the accumulated water of an outer layer of the waterproof layer is completely eliminated, and a new waterproof layer is formed; and the
grout replacing the accumulated water solidifies and condenses into a waterproof body in cracks or holes in the waterproof layer, a
liquid state of the grout is changes into a
solid state, the
water storage state above the waterproof layer is completely changed, a permanent overall waterproof layer is formed, and the repair of original leakage points is completed,so that the long-
term effect of leakage control is ensured.