Alternative to Stormsure?

[gearlessginger]

House we bought came with a yurt, 16ft I believe. Been very rainy and noticed a wet stain inside, with the water probably coming through the roof where the fire vent exits. Looking at the rest of the yurt there are a few smaller holes which need patching.
I have a local company to me who does all kinds of materials, so can get canvas, etc, at a good price.
My question is, seeing a lot of people recommending Stormsure but (boy) it's expensive, and I think I will need quite a bit.
Are there any alternatives to use to stick canvas to canvas?
Thanks