Muddha - the rushes business I did see a bit about on the recent series about some people who were restoring a medieval castle (which was otherwise fairly dull I'm afraid).
I always assumed they were 'strewn' on the floor but it looked much more like at pattern of layering & weaving. What I hadn't realised was that in peasant huts there wouldn't even be a wooden floor but bare earth, so the layers of rushes was essential as insulation, which had to be regularly topped up as the under layers rotted down into the earth, and perhaps it would only get a proper clear out once a year. A bit like having a layer of spongy, springy compost to stand or sit on rather than cold hard soil.
Must have been different in well-to-do homes which had wooden or stone floors though.