A method for fitting or retrofitting a sinter cooler, which sinter cooler has a cooler grate chain with an endless chain of cooler cars, the method including, installing a lamella grate for holding sinter material and allowing air flow through the grate so that a support structure is connected to the cooler car and a plurality of lamellae are supported by and individually movable with respect to the support structure, and are disposed to allow air flow between neighbouring lamellae, where the support structure has at least one support element disposed underneath the plurality of lamellae to support the plurality of lamellae, and at least one downholder that is adapted to limit an upward motion of at least one lamella installed such that at least a portion of the downholder is disposed above the at least one lamella.