Canvas is a good fabric to use for outdoors and is pretty sturdy. When camping or protecting outdoor stuff canvas is used. There are different types of canvas, cotton based canvas, acrylic canvas, Vinyl canvas. Each one of these canvas have their own advantages and disadvantages. Cotton based canvas absorbs moisture but is naturally waterproof as the fibers in it swell and seal the water from seeping in but the moisture itself attracts mildew and mold which are hard to get rid of. Vinyl based canvas is a waterproof fabric and doesnt need any additional treatment as long as the fabric itself is in good condition without tears but Vinyl dpesn't breathe and so in tents canvas it is hard to use this unlesss it has adequate ventilation.
The acrylic canvas is like cotton but it doesn't swell on absorbing moisture. It protects against UV radiation and is a breathable fabric, stain reisistant and comes in many colors giving the customer a great variety to choose from. But it is not naturally waterproof and so is given a chemical waterproofing coating on it which lasts a few years. but this can be lost due to rain, sun etc.In such casesan acrylic canvas can be waterproofed and so can a cotton based canvas.Waterproofing canvas is not only a good way to prevent water from seeping through but it also gives the advantage of preventing mold and mildew growth. Mildew normally comes when fabrics are exposed to moist conditions with poor air and high humidity. Canvas is used in many places such as tents, wet weather clothes, patio furniture, etc. so it is important to protect it from these threats by using a waterproof agent. Normally all canvas are water resistant but they are not waterproof. If you want to save your canvas from such threats, you need to apply a waterproof agent to the surface to repel water. Here are few tips for you to help you to waterproof your canvas.
When choosing a waterproof agent for the canvas you can go natural or commercial. You could use wax, soybean oiland turpentine mix, commercial silicone waterproofing agents but one has to figure out the type of canvas as well. If the canvas is an acrylic one, using silicone coating on it will damage the stain resistance on the acrylic canvas as these already have a waterproofing agent on them. In such cases of acrylic canvas a fluoropolymer would work best. Petroleum based waterproofing agents work better than water based agents.You can get these at a camping or hardware store. Using wax is a time consuming process and care has to be taken to fill in in the corners and edges properly. It can work well on both cotton canvas and acrylic canvas. Then there is the mix of soybean oil(2parts) with turpentine(1 part). These can be mixed together and sprayed on the canvas both sides in an open or well ventilated area. Coat it a couple of times each new coat applied after the previous coating has dried off.
Before waterproofing canvas, make sure that your canvas is clean, dry and free from all dirt and debris. You can clean the canvas by using cleaning materials like warm, soapy water with a mild detergent. Then scrub the canvas in the washing bay, using a high-pressure water, rinse it. To dry it out you can drape it over a balcony. Keep turning and refolding the tent until all of the surfaces are gets dry. If there is already mold or mildew then you have to read the instruction book that comes with your canvas to prevent damage.
Once the canvas is clean you need to find a flat surface to spread the canvas, especially a well ventilated place. Make sure choose a day when there is no wind and the sun will stay long enough for the spray to dry because canvas waterproofing requires at least 24 hours of drying in order to have an effective waterproof. You should coat at least two times in a way double coating to make the canvas safe and also be sure that you didn’t miss a spot. Spraying the underside of the canvas will add additional protection. If you are doing on furniture remove all the cushion covers and spray it on both top and bottom side to provide healthy protection and of course to help the fibers of the canvas last longer. Allow sufficient time for drying.Once your canvas is fully treated and is ready for use, remember canvas needs waterproofed at least once a season.