Canvas roofs?

[Sod Breaker]

Just wondering if anyone here has ever built a canvas roof?  I was reading in an old issue of Backwoods Home and an article about canvas roofs. The summary of the article was that canvas if stretched tightly and painted with several coats of good paint will be water tight and durable.  My idea was slightly modified.  To use a regular canvas tarp ( not blue plastic) and stretch over the pearlings and paint it with a couple coats roofing tar like the kind used for trailer house roofs.

To do a 8ftX16Ft roof I figure would cost about $150  if you go with the real heavy duty 12 oz. canvas.    It could probaly be had cheaper but that's the only kind of tarp I could find that was the right size for a 8X16 roof.


I also wonder, given that this is Minnesota if it would stay water tight with two foot of snow on it.

Sod Breaker,

[glenn kangiser]

hmm, Sod Breaker, 2 foot of snow.  That seems to possibly get to be quite a bit of weight but with a steep pitch and a solid frame and purlins, it could be a possibility.  I think rather than tar which could heat up and melt in the hot sun, I would use some of the white trailer house coating like Snow roof.  That should also stop UV from deteriorating it.  The paint would likely work also I think.

Just my ideas - maybe others have different ones.  Careful of the snow load - are ice and water in the snow a consideration also?

[poppy]

Sounds like a bad idea to me.  It would come closer to working if there was full sheathing under the canvas.

If you went with full sheathing then there would be more options for the finished roof also.

Aren't canvas roofs normally used in hot places like deserts?

[MountainDon]

Sod Breaker. From your post I can't tell if you mean to place this canvas over sheathing or to simply stretch it over rafter and purlin framing? If it is not over sheathing I can't understand how you would apply paint or roofing tar/cement.

I would think there would be a high possibility of snow load causing trouble if the canvas was over an open framework. I've lived north of MN and there is no way I'd trust an open framed canvas roof in winter.

In snow country I would recommend using properly sized rafters with at least a 4:12 pitch and applying sheathing over them. Then if I wanted a cheap roof I'd recommend asphalt roll roofing, over a layer of #30 roofing felt. . You can buy a 36 ft x 3 ft roll at HD for $45. Add roofing paper for about $40 (and you'll have leftover from the paper roll)

[Don_P]

I guess fiberglass kind of replaced doped canvas but either would work. Our camper was built '72-'74 and the 2 layer glass cloth over ply roof failed several years ago. I scuffed it up and went over it with more mat and resin. Dad in law built it dead flat  , I park it on a tilt.

This is a chicken coop but shows one way to do the roof;


My Dad's first car was an old ragtop that leaked badly. He tar and gravelled the roof. "gravel gertie" dropped gravel in every corner.

A commercial roofer could probably hook you up with a remnant of membrane to cover something that small in a seamless sheet.

http://www.ranchwillowwagons.com/sheepwagons-exteriorphotos.html

[Don_P]

I've been enjoying the pages on this site, mostly metal roofs and generally what looks to be double layer construction.
http://www.shepherdhuts.co.uk/page2.htm