By Custom Marine Fabrication | Canvas & Enclosures | 8/27/2025
Learn how to clean, dry, store, and re-treat Sunbrella, Stamoid, and Strataglass so boat canvas lasts longer in Northeast Florida sun, salt, and humidity.
Quality marine canvas and enclosures are a significant investment, one that protects your boat, your comfort, and your electronics from the elements. But like everything on a boat, canvas requires regular care to deliver its full lifespan. This is our maintenance guide, developed from years of experience building and servicing marine canvas here in Jacksonville, FL.
The single most important thing you can do for your marine canvas is keep it clean. Salt, dirt, pollen, bird droppings, and environmental pollutants break down fabric coatings and promote mildew growth.
In Jacksonville's humid climate, mildew is the enemy. If you spot mildew on your canvas, act quickly because the longer mildew sits, the deeper it penetrates. Check the fabric manufacturer's care instructions first. For many Sunbrella applications, a solution of 1 cup bleach and 1/4 cup mild soap per gallon of water can be used for stubborn mildew, but keep bleach away from clear vinyl, Stamoid, and vulnerable hardware. Apply and let sit for 15 minutes, then scrub gently and rinse thoroughly. Stubborn mildew may require a second treatment. Re-apply fabric guard after bleach treatment, as bleach strips the water-repellent coating.
For severe mildew that won't come clean, it may be time for professional cleaning or panel replacement. Bring it by our shop and we'll give you an honest assessment.
Florida's UV index is among the highest in the country, and UV is the number one cause of canvas degradation. To minimize UV damage, use canvas covers over your enclosures when the boat isn't in use, even when docked. A simple cover over folded enclosure panels can extend their life. Apply 303 Fabric Guard to Sunbrella canvas annually or as needed to restore water repellency; shade and covers are still among the most effective ways to reduce UV exposure. Park in the shade when possible; covered slips can reduce UV exposure and may extend canvas life. Lighter colors like white, tan, and light gray absorb less UV energy than dark colors, so consider that when choosing your next canvas.
How you store your canvas matters enormously.
Always store canvas clean and completely dry. Roll clear vinyl panels instead of folding them, because folding creates permanent creases that cloud the material. Use canvas bags or storage tubes for removed panels, and ensure good ventilation in storage areas to prevent mildew.
Avoid stuffing canvas into lockers while wet or dirty, folding Strataglass or clear vinyl, storing canvas in airtight containers (trapped moisture equals mildew), or leaving canvas panels lying on deck in the sun when not installed.
For Northeast Florida boaters, a practical schedule looks something like this.
In spring (March-April), do a deep clean of all canvas and enclosures, inspect stitching and seams for wear, check zippers and snaps for corrosion or binding, apply fabric guard to Sunbrella canvas, and polish all clear vinyl panels.
During summer, rinse after every use and do a monthly cleaning as described above. Check for mildew regularly since the combination of heat, humidity, and afternoon storms creates ideal conditions.
In fall (October-November), do a full cleaning before winter storage, inspect all components for damage that needs repair before next season, and apply fabric guard again if canvas has been cleaned frequently during summer.
During winter (December-February), if your boat is stored, ensure canvas is clean and dry. Open enclosures periodically to allow air circulation, and inspect for any rodent damage if stored on land.
Sunbrella canvas should be re-waterproofed with fabric guard whenever water stops beading on the surface. A simple test: sprinkle water on the fabric. If it beads up and rolls off, the coating is intact. If it soaks in, it's time to re-treat.
Typically, canvas that's used regularly in saltwater needs re-treatment every 6-12 months. Canvas on boats kept in covered storage may only need treatment annually.
A little regular maintenance goes a long way. We've seen Sunbrella canvas last 10+ years and Strataglass enclosures last 5+ years on boats in Jacksonville, but only when owners commit to consistent care.
Need help with canvas repair, replacement, or just want some maintenance advice? Give us a call. We're happy to help you get the most out of your marine canvas.