The invention relates to a flat-joint and detachable type roof deformation joint and a construction method thereof, and belongs to the technical field of buildings. The deformation joint is characterized in that the interiors of
reinforced concrete structure beams at the two sides of the deformation joint are embedded with round steel, each
reinforced concrete structure beam is provided with an angle iron, the outer side of each angle iron is provided with a concrete retaining sill, each angle iron is provided with an additional waterproof layer, a detachable rubber
water stop belt is arranged between the two angle irons above the deformation joint, and is provided with a steel plate pressing strip, the steel plate pressing strip, the detachable rubber
water stop belt and the angle irons are screwed, fastened and connected through nuts and threads at one ends of the round steels, a roof waterproof layer is provided with a roof heat
insulation layer, a leveling layer and a roof rigid protecting layer, a deformation
joint heat insulation layer is arranged between the two angle irons, a cover plate is arranged in the roof rigid protective
layers, a gap is formed between the cover plate and the roof rigid protective layer, a flexible plate strip is arranged in the gap, and the upper part of the flexible plate strip is fully embedded with
sealant. The deformation joint has the advantages that the setting requirements of various deformation joints, such as earthquake-proof joints, telescopic joints and settlement joints, are met, the strength is high, the wear-resisting performance is good, and the maintenance is convenient.