A pop-top canvas has a harder life than a tent. It is folded every time you drive, often closed while still wet, rubbed against the roof frame, and left in the sun for years. We chose our fabric for exactly that job: PU-coated 600D Oxford polyester. And on every canvas we make, we tape the stitched seams on the inside. Here is how the common canvas fabrics compare, and why we think ours is the right one for a pop-top roof.
In short
- Our canvases are PU-coated 600D Oxford polyester. It dries fast, folds in the cold and takes the rubbing.
- We tape every seam on the inside, so far less rain gets in at the stitching.
- It is water-resistant, not waterproof. Air the van to keep condensation down.
What a pop-top canvas has to survive
- Folding. The roof goes down every time you drive, in summer and in frost.
- Closing it damp. On the last morning of a trip the canvas is often wet when you pack up.
- Rubbing. Where the fabric meets the roof frame and hinges, it rubs on every opening and closing.
- Sun. A roof spends years on top of the van, in full sun.
- Rain on the seams. On a well-made canvas, water rarely gets through the fabric first. It gets in at the stitching.
Pop-top canvas fabrics compared
Cotton canvas
Breathes well, so there is little condensation, and it is quiet in wind. But it is heavy, heavier still when wet, and it needs a few rounds of wetting and drying before it sheds water properly. Folded away damp, it gets mildew and can rot or shrink.
Polycotton (polyester-cotton blend)
Breathes nearly as well as cotton and is lighter and more stable. It still takes up water, so it can mildew if it is stored damp.
Acrylic (awning fabric)
Keeps its colour in strong sun for many years and the fibre doesn't rot. Its water repellency comes from a surface finish that wears off and needs renewing. Stiffer to fold.
PVC-coated polyester
The fabric itself is waterproof and easy to wipe clean. It is also heavy and stiff, especially in the cold, doesn't breathe at all, and the coating can crack along the folds after years of opening and closing.
Nylon ripstop
Very light and hard to tear. It stretches and sags when wet, and sunlight weakens it faster than polyester.
Why we use PU-coated 600D Oxford polyester
For a pop-top roof, it does best on the things that wear a canvas out:
- It doesn't rot. Polyester takes up very little water and dries fast, so closing the roof damp on the way home does no lasting harm (dry it as soon as you can, though).
- It folds. The PU (polyurethane) coating is a thin, flexible layer, so the fabric stays soft and easy to fold, also in the cold. Thick PVC coatings are much stiffer.
- It takes the rubbing. 600D is a thick, heavy yarn. Thinner polyester (210D, 420D) wears through faster where it rubs on the frame.
- It keeps its shape and handles sun. It doesn't shrink or sag when wet, and stands up to sunlight better than nylon.
- It sheds rain. The PU coating helps the fabric keep water out, and the tight Oxford basket weave is hard to tear.
The honest trade-off: it is water-resistant, not waterproof. Normal rain runs off. If it rains hard for hours, or water sits on the canvas while the roof is folded, some can still come through. Because of the coating it breathes much less than cotton, so ventilate (more on that below).
Then we tape every seam
Every stitch is a small hole through the fabric, and the thread can carry water along the seam like a wick. In long or heavy rain, drops work their way in along the stitching, around the window frames and at the corners, where several pieces of fabric meet.
Good tents and rain jackets deal with this by taping their seams. We think a canvas you sleep under deserves the same. So after sewing, we tape every seam on the inside of the canvas. A hot-air machine melts the glue on a strip of seam tape and presses it over the stitching, so it bonds to the PU coating. The tape covers the needle holes and the thread, so water has far less of a way in. It stays flexible and folds with the canvas when you close the roof. It doesn't make the canvas waterproof, and we won't call it that, but our canvases are noticeably better in the rain than before we started taping the seams.
Drips inside are not always a leak
On cold or wet nights, the warm, damp air from breathing and cooking turns to water on the inside of the cold canvas. Those drops look like a leak but come from inside the van. It happens with any coated fabric, ours included. Opening a window or the mesh a little, even in the rain, lets the damp air out and cuts condensation a lot.
Do you still need waterproofing spray?
For normal use, no. A new canvas with taped seams is ready to use. If you often camp through long rainy spells or in winter, a few thin coats of waterproofing spray on the outside help the fabric shed water for longer. The tape closes the stitching; the spray helps the fabric itself. How to apply it is in our canvas care and waterproofing tips.
Looking after the seams
Let the canvas dry fully before you close the roof for storage. Wash with mild soap and water, and don't aim a pressure washer at the seams. Look along the seams once a season. If the tape ever lifts or a seam gets damaged, a tube of seam sealer from an outdoor shop is enough to touch it up.
Questions to ask before you buy any canvas
- What is the fabric, and how heavy is it (for polyester, the denier)?
- Is it coated, and with what?
- How are the seams made: just stitched, or taped as well?
- Can you see photos of the inside of a finished canvas?
Our answers: PU-coated 600D Oxford polyester, every seam taped on the inside, and the photos are above.
Which canvases have taped seams
All canvases we make, for every van we cover: VW T3 / T25, VW T4, Ford Nugget, Opel Vivaro and Mercedes Marco Polo, as well as custom-size canvases. Not sure which one fits your roof? Read Before you order a pop-top canvas.
Written by Kaspars Stabulnieks, co-owner of Toptrail. We sew every canvas in our own workshop in Latvia. Why we built Toptrail.
