Mildew: THE Number 1 Battle For a Bell Tent

‘Praemonitus, praemunitus’ or ‘forewarned is forearmed’…

As an ex-bell tent manufacturer of 15 years, we’ve seen first hand the utter devastation mildew can cause to a bell tent.

Here we share with glampsite owners the most common causes and how to avoid it. However, a lot of the advice can be applied to anyone owning a bell tent.

What is Mildew?

Definition: From the Encyclopaedia Britannica;

Mildew is commonly associated with damp cloth, fibres, leather goods, and several plant diseases (downy mildew and powdery mildew). Mildew-causing fungi use these substances as sources of food for growth and reproduction. Mildew often produces a distinctive smell. The terms mould and mildew are sometimes used interchangeably.

What Does Mildew Look Like?

Here is a rather extreme example of mildew formation on a bell tent:

Occurrence & Avoidance

Once mildew forms it can be near impossible to remove, and so prevention is key. The most common reasons for mildew forming on a bell tent are:

Lack of Ventilation

We’ve discussed extensively how bell tents were originally designed for touring. A tourer will pitch their tent for short bursts, and while using their tent they will frequently open and close the entrance and windows on a daily basis. If you don’t have bookings, your tent might stand unused (for days or even weeks) and so you will need to take the time to ventilate the tent, allowing the air to refresh and recirculate inside the tent.

We’ve also witnessed issues when the user has attached a secondary structure to the outside of the tent. This might be a secondary tarp, a canopy at the entrance or a ‘tent protector’ – anything that is in contact with the canvas outside the tent that can attract moisture and restrict airflow.

Non Replenishment of Treatments

Mildew just loves damp conditions. Most bell tents are pre-treated at source to be water resistant but by using bell tents for long periods of time, these treatments will disperse more quickly. By regularly replenishing the canvas with a water resistance treatment, you will discourage mildew from forming.

Most treatments also include a resistance to UV (Ultra Violet light from the sun). So be sure to select one that includes this, such as Granger’s Fabsil Protector with UV. The Nikwax brand range includes a wide selection of treatments for cotton canvas too.

If we consider that the average touring tent user will apply a treatment to their cotton canvas bell tent once a year, after around 5-6 weeks of use, then it’s easy to see how frequently you must apply the treatment to your tents if pitching for months on end.

If you are pitching for, say, 125 days each year (see chapter Revenue/Season Length) you should consider applying the treatment a minimum of three times during a regular season:

125days/7 = 18 weeks of continual use (rounded)
18/treatment every 6 weeks = 3 times a season.

Applying the treatment is straightforward. Five litres of Fabsil is enough to treat one 5m bell tent. The liquid is poured into a pressurised container and a fine sprayed onto the outer surface of the tent, with priority given to the roof, then the walls, then the entrance.

Spills

Not so common, but spills left undealt with are often moist and a great source of ‘food’ for mildew. In worse cases, spills are left in situ and the tent is packed away into storage. When taken out of storage the original area affected by the spill has increased and is now covered in mildew.

Cleaning of problem areas with a mild detergent will halt the spread of mildew. Remember to use a cleaning agent specifically intended for cotton canvas tents and to retreat the area with Fabsil, even if only spot cleaning.

Poor Storage

Way too often, around March/April/May (when users first take their bell tent out of winter storage) the owner of a bell tent will discover their tent is affected by mildew. Commonly, it’s because the tent has been put away damp, but it can also be due to ambient moisture levels in the storage area, or because there has been an inlet of water in the storage area without the owner knowing.

We’ve suffered losses in this way too. We had a bell tent stored in a regular, wooden shiplap shed without realising some vegetation had grown into the shed (in between the shiplap) and was in contact with the tent. This was conducting water along the vegetation and onto the tent. Luckily, only the outer canvas carry bag was affected by mildew and we were able to replace that easily. Had we left it longer than the winter period it had been there, the mildew would likely have spread to the rest of the tent within.

Garages, sheds and outbuildings can all present issues with regard to dampness. The best place to store a bell tent is inside the home, but this is impractical if you have a multitude of tents to store. The storage issues alone are a good reason to sell-off your tents at the end of the season, and start with fresh ones each year.