Winter Tent Prep – Natural Mould Treatment

My beautiful canvas tent has gone mouldy with the autumn rains, and I’ve been learning how to treat it and get it ready for winter. I was expecting that this would happen, and I have tested out various natural mould treatments before. But my tent is my home, so I need to know that the treatment will work! I quickly tested out several ideas on outside sections of the canvas:

Rubbing a paste of bicarb soda into the mould (didn’t seem to make much difference, although it lightened the mould a bit)

Clove essential oil diluted in cheap alcohol and water (50-50 vodka and water, with a teaspoon of clove oil per 200ml; expensive to saturate the canvas, resulted in yellowing, and created extremely strong fumes for a few days; don’t sleep inside a recently treated tent! It didn’t remove the black mould appearance, and didn’t have any visible effect on mould growth, although I’ve used it very successfully in the past to treat mildew on a bathroom ceiling)

Vinegar (didn’t seem to make much difference, and is corrosive to the canvas, poles and metal zips)

Strongly salty water, dried and then brushed off (it rained too soon to observe a salt crust; didn’t seem to make any difference; also corrosive to metal)

Steam cleaning (this kills the mould spores, although it also creates a lot of hot moisture inside the tent; but in the end, any other treatment involved getting the tent thoroughly wet also. The steaming worked the best out of the above five methods, but still left the mould mostly visible)

In the end, I followed the instructions of the tent manufacturer and applied a strong bleach solution (1 part bleach to 3 parts water) with a clean broom. This corroded the inside of the metal poles a little, so I had to later dismantle the tent and rinse the poles inside.

It also caused the stitching to fall apart in one section, which I repaired with dental floss.

Despite these drawbacks, the bleaching did remove all the mould, stains and dirt, restoring the pristine airiness of the tent.

I bought a new broom and garden sprayer to apply the bleach with, as well as masks and gloves. All that plastic! 🙁 I used gloves and goggles to apply the bleach solution. Inside the tent, I also used gumboots for puddles and a facemask to avoid breathing in the strong chlorine gas.

The mould grew very quickly once it had appeared, and the inside of the tent was becoming covered faster than I realised. I treated it section by section. I used two brands of bleach, and one created foam while the other didn’t; I don’t know what other chemicals and cleaning agents were in them.

Don’t use a black rag to apply bleach… silly me! Almost stained the inside of the tent with the dye!

The outside of the tent stayed white from the bleaching effect of sunlight. I don’t know if the inside surface had been waterproofed or not, and whether this had an effect on the rapid mould growth there.

Also, the thicker grade of canvas used on the lower sections of the tent was much more mould resistant. I probably should have bought the more expensive version of my tent, which had thicker canvas all around.

Even where I have bleached both sides of the canvas, in sections that have a double layer I can still see mould inside. I think this is what they mean when they say that bleach doesn’t remove the mould; it’s only good on hard or thin surfaces. The section that I steamcleaned first has less visible mould, so I’m going to steam treat all the double flaps before I apply the waterproofing again (because the steamcleaning removes the waterproofing).

It was much harder to apply the liquid overhead on the sloping walls than it was on the outside. I eventually learnt to climb the ladder so that I was always reaching sideways rather than over my head, and to shake excess solution off before I raised the broom to the tent wall. Otherwise most of the bleach fell on the floor. As it’s a clean waterproof floor, sometimes I swept it up and reapplied it to the walls.

It felt strange to be using the hose inside the tent! The bleach solution stays on for fifteen minutes, then must be rinsed off promptly and thoroughly so that it doesn’t eat away at the canvas. Possibly the top section of stitching that fell apart was overbleached from being left too long. The autumn rains were helpful to rinse out any remaining bleach.

I couldn’t reach the top of the ridge section while the tent was erect, or treat underneath the ridgepole, so I filled an esky with bleach solution and immersed this part of the tent while it is dismantled. These pictures show the ridge section prior to mould treatment, and after treating both inside and outside. I couldn’t reach the very highest strip.

Now that the mould has been removed, the waterproofing agent has also been stripped away, so I need to re-proof the canvas. This is a whole other ball game! I didn’t get it done quickly enough, and while the tent was empty and not well pegged down a winter storm blew it over into the mud…

…makes me want to cry! After all that cleaning!

So first I’m going to give it a scrub on a wet winter’s day, so the rain can help to wash the dirt off, then wait for a dry day so I can pack it up. It folds down to two small bundles. I’ll get on with the reproofing business in spring.

My son’s tent has also failed, with the stormy weather. It was never going to last out the winter. The ropes were frayed and the nylon was brittle. Although it looks broken, the internal section is still quite intact, so I’ll keep it for summer use as an insect-proof shady space. I had to rescue the remaining furniture and toys from puddles of water a few weeks ago. Luckily I had already moved all the precious stuff and the rugs out.

Meanwhile, I’ve moved into two housetrucks for the moment and have a housesit lined up. So I’m not a tentdweller until at least spring. We also had a short stint in a little shack. I’m pretty much testing out all the options. I do miss my tent, but it’s cosy in the housetruck and I have the best soap studio ever – it’s my she shed!