I use rubber mats which are about 2-2.5 cm thick they have drainage ribs on the underside ( they were sold a stable mats rather than anything else) I also use them with straw over concrete. the floor is not completely covered by the mats just where horse stands & lies. Generally there is no more smell than a normal straw bed until you move the mats & all the uck is underneath, I take the mats out of the stable 2-3 times / year ( the mats are heavy & its really a 2 man job with gloves) and wash the floor allowing it to dry & give the mats a good sluice both sides.
