Plastic foam is 0.10 times as dense as water. What weight of bricks could you stack on 1mx1mx0.10m of foam...?

Plastic foam is about 0.10 times as dense as water. What weight of bricks could you stack on a 1m x 1m x 0.10m slab of foam, so that the slab of foam floats in the water, leaving the bricks dry?