C-Gear Here to - Great Product for minimizing Dirt\Sand Coming in, It is a little abrasive though just like shadecloth, probably not as bad as shadecloth..
Apart from being Bulky you really cant beat a stack of the square interlocking foam matt's IMO... Every now and then K-Mart sells packs of 6 for about $12 we now have enough to fill the whole annex area and use them in the garage when not camping - I use the ones with the holes in them this way dirts finds its way down and if it does rain then we have slightly more chance of staying dry in the annex given they are about 20mm thick.