Re: Buying canvas for dojo
I was a sailmaker many years ago and I've made a few mat covers over the years.
I think that the last couple I've made I've used 10oz canvas. If you're not sure what weight you want to use ask for samples. You will find that the biggest difference between the weights is the number of threads per inch, with the heavier weights having fewer threads per inch. So the heavier you go the coarser the texture, and the worse the mat burn factor. The 10 oz seems like the heaviest you can go without having something with a surface like sandpaper. The one we have now has been on about ten years or more and is holding up very well.
If you find the right supplier you should be able to get 8, 10 or 12 foot wide canvas, so you can work out what will fit with the least waste and fewest seams.
Personally, I would not use a coated canvas because I like the appearance and feel of the surface that natural canvas gives. People that are used to other surfaces sometimes comment that it seems slippery, but I think it is all in what you get used to.