Permeable ground sheet / mat in front of tent

[wineymummy]

When we were in France last year we noticed lots of the tents had big sheets/mats pegged out the front of their tents. Solid enough to provide a barrier to the mud but water could drain through so it wasn't a mess (can you tell we had a bit of a soggy holiday...) These mats looked to be almost stretchy, they were pulled quite taut. Anyone got one and can recommend? Or tell me what I should be looking for?