I did a little more research on Tyvek. Tyvek Homewrap is available at some home stores and has a base weight of 1.8 Oz. per Sq, Yd. Typar is a different product made in a different way, but looks a lot like Tyvek. Tyvek Softwrap is a lighter weight product made for packaging materials. There are actually several different types of Softwrap and the base weight is 1.27 Oz. Per Sq. Yd. What I have found so far is available in 54 and 60" widths. Cut to length Tyvek is pretty pricey and still only 60" wide max. Hard Tyvek is the paperlike material used in envelopes and is different from Soft Tyvek, which is mostly used for packaging. Remnants of Tyvek are often available on eBay, but will require some time to sift through them to find something desirable at a decent price. Tyvek Tape is probably made from hard Tyvek. It may make good tieouts, but may not work very well for seaming. I've got a roll, but haven't tried it yet. Tyvek Flashing Tape is probably not usable since it has a Butyl Rubber adhesive. Tyvek is sold as waterproof breathable, not waterproof. The water penetration resistance quoted is quite high, but I don't know how well it really performs.