[MR] Canvas

[Alexandria Stratton]

Canvas is naturally water resistant; when it rains, the fibers swell & seal out the rain. In very heavy (pounding) rains you may have a misting inside your tent. You can avoid this by putting a liner inside your tent (period), but that's another conversation. 

All canvas will shrink in the sun, relax in the rain, and shrink in the sun again. All canvas will mildew if it is packed up & stored with any moisture whatsoever. Keep it dry and take care of it, it will last you a lifetime. 

Untreated canvas: To pre-wash & iron it is unnecessary. Make your pavilion, set it up & hose it down (or wait for rain) to wash the sizing out of the fabric. It may leak with the hose, but once the sizing is washed out it will seal out the rain nicely.

Sunforger is a treatment applied to canvas for resistance of mildew and/or flame. Any scrubbing or cleaning chemicals will remove the finish. 

Sunbrella is a polyester material (will not shrink) and comes in a variety of colors. It is expensive (60"w is usually about $18/yd) but the color is guaranteed not to fade for 5 years and it is mildew resistant. I'm not sure if it is resistant to flame, I have never looked.
Note: the dormer roofs & awning on my pavilion are made with Sunbrella (mediterranean blue). In 8 years they have not begun to fade at all.

Use a garden sprayer on your hose if you need to clean a large section (water pressure) or spot clean with a damp rag. If you have mildew, set it out in the sun. Mother Nature will bleach it for you.

There are a few vendors around, an average price for 60"wide Sunforger (flame retardant) is about $7.50/yd. I have purchased from Hamilton Dry Goods in the past but I think they're having life issues and their customer service has gone downhill. 

I plan to purchase from ITEX in the near future. I have heard wonderful things about them over the years. Dan Love is the agent that handles the Sunforger sales and the prices are awesome.
I talked to him last week, these are the prices he gave me (its 10oz by the way):
36" wide Sunforger $2.75/yd
36" wide Sunforger (flame retardant) $3.95
57" wide Sunforger $4.05/yd
57" wide Sunforger (flame retardant) $5.75/yd
Itex does not sell cut yardage, you must buy it in 100yd rolls. So if your project only requires 40-50 yards, you could pair up with somebody that has a similar project and split the cost.

If you are interested in tent-making, you might consider joining the Medieval Encampments list. Please look through the files, photos and links before you start asking questions, though. 
http://groups.yahoo.com/group/MedievalEncampments/?yguid=196438763
Another neat site to peruse is Mistress Mira's Medieval Pavilion Resources website:
http://www.currentmiddleages.org/tents/index.html
The site is huge, so set aside some time to look at everything.

 -- Ceara ní Néill
http://www.HouseBarra.com
Experience is what you get, when things go awry.