Waterproofing industrial textiles: what actually keeps water out

Why it matters beyond staying dry

Water getting into a textile does three things, and only one of them is obvious. It makes the thing wet. It also feeds rot and mildew in natural fibres, and it accelerates the breakdown of stitching and coatings from the inside. A cover that's merely water-resistant will often fail at the seams and fixings long before the fabric itself gives up.

For anything that lives outdoors in New Zealand, waterproofing is really about service life, not comfort.

1. Coating

A waterproof layer — PVC, polyurethane or silicone — is applied to one or both faces of a base fabric. This is what most industrial covers, tarpaulins, curtains and truck sides are.

Coating is completely waterproof rather than water-resistant, and the coating can carry other properties at the same time: UV stabilisers, fire retardancy, anti-fungal treatment. The trade-off is that it doesn't breathe at all, so anything sealed underneath it will sweat unless you ventilate it deliberately.

• Best for: tarpaulins, machinery covers, PVC curtains, water bladders, truck curtains
• Weakness: zero breathability — condensation forms underneath in temperature swings

2. Laminating

A separate waterproof membrane is bonded to the fabric. The membrane blocks liquid water but lets vapour through, so the material breathes while staying waterproof.

This is the expensive option and it's used where breathability genuinely matters — high-performance outdoor gear, some marine applications, technical clothing. For a machinery cover it's money spent on a property you don't need.

• Best for: applications where trapped moisture is the problem, not the rain
• Weakness: cost, and the bond can delaminate with age and flexing

3. Waxing and proofing

The oldest method: paraffin or wax impregnated into the weave. Traditional canvas is proofed this way, and it's still the right answer for a lot of canvas work.

Waxed canvas breathes, ages well, and can be re-proofed rather than replaced — which is the key point. A proofed canvas cover is a maintenance item, not a disposable one. It won't match a PVC coating for outright waterproofness, but it will still be serviceable in twenty years if it's looked after, which coated fabrics generally won't be.

This is why we recommend an annual re-proof on canvas ute canopies and awnings. It's a small job that resets the clock.

• Best for: canvas canopies, caravan awnings, traditional canvas goods
• Weakness: needs periodic re-proofing; not fully waterproof under sustained pressure

4. Dense weave

Tightly woven natural fibre swells when wet, closing the gaps between threads and becoming effectively waterproof without any coating at all. Traditional canvas tents work on this principle.

It's elegant and it breathes, but it has a well-known catch: touch the inside of a densely-woven canvas while it's wet and you'll break the surface tension and start a drip. It also needs to be weathered in — a brand-new canvas often needs a wetting and drying cycle before it fully seals.

• Best for: traditional canvas where breathability matters more than absolute waterproofing
• Weakness: needs weathering in, and doesn't like being touched when wet

So which do you need?

If it has to be absolutely waterproof and breathability doesn't matter — a tarp, a machinery cover, a water bladder, a PVC curtain — you want a coated fabric.

If it covers something that will sweat, or that you'll be inside, canvas that breathes will serve you better even though it's technically less waterproof. That's why we still make ute canopies and caravan awnings in canvas rather than PVC by default.

If you're not sure, tell us what the cover has to do and where it lives, and we'll tell you which one and why.