Mould - the enemy to most camping equipment that are made with fabrics - think tents, rooftop tents, chairs, equipment bags/covers & even your apparel you might store away like snow gear. Once it sets in, it's hard to bring your gear back to its original condition - sure it can be cleaned off, but getting rid of the pores or the smell of cleaning agent is difficult, plus most elbow-grease usually leaves some wear & tear in patches on your equipment.
So, rather than get rid of it try to prevent it in the first place especially in rooftop tents that are an expensive investment & continually exposed to the elements. Here are some tips...
Tip #1 - Store your rooftop tent ladder separately
It's easy to fall into the trap of thinking that only the fabric (where you usually see mould) needs to be dry. The biggest culprit is in fact your ladder. Most ladders are telescopic and expand from the bottom rung, which means moisture (rain and condensation) run down and into the cavity of each section of ladder. So while your fabric will dry in less than an hour (given warm temps and direct sun), your ladder will still contain moisture that will eventually provide the perfect environment for musty stank and worse, mould. Even soft-top rooftop tents have detachable ladders - a bit more effort to undo the bolts, but worth doing!
Tip #2 - Reduce condensation in your rooftop tent
Condensation is part and parcel to camping. Even expensive, well-made gear - tents, rooftop tents, vehicles, etc - all suffer from condensation. Just like how your shower at home fogs up and creates water droplets, so does any contained space with changing temperatures or moisture in the air. Your rooftop tent will suffer condensation in different ways depending on the design, materials, number of people sleeping in it, what the climate is like where you camp, what your precise location is (in a valley v's hilltop). But you can't escape it - simply understand it and manage it.
Moisture build-up and condensation in camping tents and rooftop tents is caused by the changing temps in your surrounding - leading to a difference inside and outside of your tent. But it's mainly caused by the incredible amount of moisture in your breath during the night. So, add more people in a small space and the problem gets worse.
Ventilation is key here - at a minimum you need plenty of open windows - and yeah, even in winter you'll be amazed at how warm your tent will remain even by leaving a couple of windows cracked in your tent. Remember you need more than one window for air to come in and escape to create a breeze. You should also consider your entire sleep system and not rely on a tent solely to keep you warm - insulation underneath you, your sleeping bag/comforter insulation, your multi-layered clothing - they'll all keep you warm and snug while your rooftop tent ventilated and really keeps you protected from the outside elements.
"One sleeping person adds half a pint (230ml) of water to the air overnight" That's almost a can of drink.
Tip #3 - Wrap your flooring/poles in fabrics
Ok, so this one might seem counter-intuitive, but stick with me here. Condensation isn't a problem - it's the run-off of the moisture and when it builds up that causes the discomfort physically, psychologically and with mould. Your poles and other metal components will change temperature the fastest and the droplets will form running water faster (versus fabrics that will absorb it to a certain degree). Some Rooftop tents have exterior poles and gas struts that aren't a problem! Softtop rooftop tents usually have an internal frame - cheaper ones have exposed aluminium and others might have fabric coverings. It all needs to be dried at the end of the day because the moisture still remains, but the fabrics will capture the droplets when they form so it doesn't touch your skin or sleeping gear.
Some people put carpeting down on the cold hard flooring - not a bad move, but it will be a lot to manage - it still needs to be dried, but it also adds weight to your rooftop tent which is the thing we're all trying to minimise (check out our other post on weights - give or take).
Tip #4 - Modify your rooftop tent
Try adding new components or swapping out stock ones to make you more comfortable and help with drying your rooftop tent. We often use condensation mats to create a buffer between the rooftop tent flooring and the mattress - it doesn't do a great deal while you're sleeping but will help create some airflow where moisture can build up - but it doesn't hold onto the moisture like a carpeted base layer would. Swap out a stock foam mattress for a self-inflating mat - this doesn't do anything for condensation, but does make it easier to remove the mattress for drying separately to your tent. We use (and sell) Exped Megamats which are incredibly insulated which makes Rooftop tent camping very comfortable and easy to manage. You can roll it up into a coil and let it sit in the sun easier and cleaner than a stubborn foam mattress.
Tip #6 - Check the exterior of your rooftop tent cover regularly
There are pros and cons to every shape and design of a rooftop tent - the biggest difference is the exterior - either a hardshell or soft shell. Then different designs and materials used can influence moisture collection or build up in a variety of tents. It goes without saying the more expensive tents are more waterproof - mostly!
When you have a soft shell tent, you'll need to check regularly for stone chips, wear and tear from usage, bugs (road kill) and UV exposure. Rain can build up through those small holes/teras. If you have tents without a seal at the front (of the car) then you can get rain bounce off the roof and eventually up into the tent - so these might need to be aired/dried regularly if on your daily driver.
And many hardshell rooftop tent manufacturers still pop rivet the roof - grab some silicon sealant and also consider Raptor coating the entire roof - it'll provide a great seal, tougher exterior and looks great too.
It's a lot to look after, but your RTT cost you a lot of money in the first place!
It takes quite a bit of effort to maintain your equipment including your rooftop tent. Much the same for any and all outdoor gear. Sometimes you need to add a little bit of extra and enhance the original product, sometimes you just need to spend some more time taking precautions or preventative measures. You can also limit the amount of time a rooftop tent is exposed to moisture by allowing it to be aired/stored indoors - but who has the room to do that? We can store many styles of rooftop tent for a fee - with our hoist available for easy off and on: Click Here to learn more. Or simple rent one of our rooftop tents and you'll never have to worry about mould or airing a tent again (except while you're out on your adventure). Got any other tips? Add some below.