Mold Avoidance Paradigm

This article focuses on the healthiest trailers. The first priority is that the trailer holds up to mold. If it doesn’t hold up to mold, no amount of natural wood, or wool, or other eco-friendly material really matters.

Conventional trailers are extremely mold-prone. They use wood within the walls, roofs, and floors with a design that is not airtight. Condensation usually forms in the cavities. They are also prone to leaks.

The Designs That Best Hold up to Mold are:

1. Sandwich construction – Airtight cavities of metal or fiberglass with rigid foam insulation. Ideally laminated together.
2. Fiberglass shell campers – Solid fiberglass body trailers are single or double hulls. A single hull has no hidden cavity where condensation or mold can form. The double hulls can work well too. I list brands that have minimal wood or where the wood does not become a mold risk.

Low-VOC Trailers:

No well-made trailer is extremely low in VOCs. Some are better than others.

The interiors of all-metal trailers can be lower in offgassing compared to trailers with other wall materials. But don’t underestimate the odors of the glues used in all metal trailers.

There is no getting around the offgassing. The best strategy is to give it some time to offgas or buy a used one if you are highly sensitive.

You certainly can compare models though if you are chemically sensitive since we all are reactive to different chemical combinations. You definitely could find some brands more tolerable than others, even if the total VOC count is the same.

You should also use mitigating strategies like a bake out, and shellac to block the offgassing. Shellac is ideal on metal, fiberglass, vinyl, and many other materials. You can remove shellac later with alcohol.

Some brands are formaldehyde-free but that has not been a big focus of mine since there are many other chemicals used in the construction of trailers.

Updated Winter 2020/21

There is no affiliate or sponsored content in this post.

Trailers for Chemical and Mold Sensitive Folks

1. Metal Travel Trailers

ATC Aluminum Toy Hauler

ATC is a mix between a cargo trailer and a high-end trailer. They look industrial compared to the Living Vehicle below (made by the same factory).

They claim to have no wood whatsoever and similar construction to the old Camplite design. They do have fiberglass insulation in the ceiling but the rest is foam.

The interior walls are Azdel.

The 24″ units have a bath, kitchen, eating area, couch that is made into a queen bed, and extra cabinets.

Bryan Rosner, a mold-sensitive person, has a good video tour of one here.

Cost – The 20 ft base model with no upgrades starts at $38,390 USD. The 24 ft models start at $41,530 USD. When a client priced it out with taxes and fees and the options she wanted, it came to 55k.

Weight – The 20 ft base model weighs 4,500 lbs.

Camplite

I had a Camplite by LivinLite travel trailer made to my specifications and you can find all the details about that here.

The key thing I look for in a trailer is moisture-proof walls and laminated sandwich insulation.

This laminated metal-foam-metal was the key to moisture-proof walls in these old models.

You may still find a used one with sandwich laminated walls before they changed the wall system. The company is now out of business.

Cost – You can find a used 2014 (21 ft) for 18,000 USD (or less, depends on the size).

Weight – A 24 ft model weighs about 3,100 lbs (depends on the year and configuration).

Hero Camper

A new to me trailer, the Hero Campers are the most ideal design. The walls, floor, and ceiling are all a sandwich construction just like the old Camplites, except those didn’t have insulated floors.

I was really excited to find this one. The envelope is constructed of fiberglass (on the outside)-foam-metal. Perfect. The best construction for mold prevention.

The interior is metal which is great for those with chemical sensitivities, though keep in mind all new trailers have offgassing from the construction adhesives.

It has a small kitchen on the exterior, two options for heater types, no bathroom.

This is a European company, they have many dealers throughout Europe. They also have a dealer in Arizona, one in Australia, and one in Israel.

You can rent one in California on Outdoorsy.

Cost – The 2021 Hero Ranger is going for $21,995 USD through Tom’s Camperland in AZ.

Weight – The Hero Ranger is 15.8 ft and weighs 1,911 lbs.

The Safari Condo

The Safari Condo is another great option to consider. A bit of a hidden gem, this one.

The roof and walls are made of a “sandwich-type material with a plastic honeycomb core laminated with Alufiber on one side and aluminum on the other.”

That main core is not foam or fiberglass insulation, it’s a honeycomb polypropylene.

Alufiber is an aluminum and fiberglass product.

This sounds like a very moisture-proof design to me.

They say the only materials used in the Alto body are aluminum, Alufiber, plastic, Formica, and glass. The furniture is mostly made of aluminum and composite materials.

They need a fair amount of time to offgas for most sensitive people, though some less sensitive have used them brand new. I have heard from one person who found this trailer to be higher in offgassing than most other trailers.

Cost – Their travel trailers start at $37,500 Canadian Dollars. The more popular 1713 model (17 ft) has the pop-up roof (built well) and that one is about $40,000 Canadian dollars.

Weight – The 17ft (1713) model is only 1,825 lbs.

Custom Metal Trailers

Customised

You can customize a small metal trailer custom-made in the style of the Camplite, or more like a tiny home on wheels. Customizing these structures tends to get very expensive. And it’s not common to find someone with this expertise to build them. It’s better to work with a company that makes metal trailers already and make some alterations.

Metal SIPS

I have also seen cargo trailers and larger homes on wheels custom made with metal SIPS. This is metal-foam-metal laminated together. A very watertight construction if done well. It is supposed to have another siding on the exterior of the SIPS.

Porcelain Enamel

Another type of non-toxic trailer is porcelain enamel on steel. This is an extremely tolerable material but it is not cheap. It’s very rare to see a porcelain trailer for sale, many of them were made on poor quality RV shells which is a shame because the porcelain enamel is highly tolerable on the interior.

If you find one for sale you may be able to use the interior to rebuild a trailer around.

Cargo Trailers

Weeroll

The Weroll is similar to a cargo trailer but is more customized and you may be able to reduce the off-gassing with this option as well as streamline the process of converting it.

Those who bought the Weroll seemed to tolerate them right away. Probably due to high level of customization.

But insulating a cargo trailer, including a Weeroll, is no simple project. My post on vans describes the process.

As of winter 2021 I don’t recommend this trailer for sensitive folks. I’m waiting to hear more updates before removing this from the list.

Cost – The Weroll all-aluminum Silver Eagle 10 x 6 ft with insulation (no kitchen and bathroom), wired with outlets is $9,500.

Weight – Depending on height and options, the 10 ft can be as light as 1,080 lbs.

High-End Metal Trailers

Airstream

Airstreams with metal walls are far more tolerable for the chemically sensitive than most other trailer options that have a kitchen and bath.

The metal airstreams (they do have fiberglass ones now too) are metal walls and metal ceiling with, obviously, metal exterior skin. The flooring is vinyl over a plywood subfloor.

The offgassing is not too bad and does go down at a reasonable rate. The resale value is quite good for a trailer/RV.

I like the metal interior walls, they cut down on offgassing and they are way better made than your typical wood-framed crappy RV.

Some of their showrooms are inside warehouses which may help preserve them.

However, this needs to be 100% airtight on the inside walls and the exterior walls to not have vapor get between those skins where it will be mostly doomed to not come back out. (Some caveats would be that if you never heat or cool this then it’s not really a worry, unless it actually leaks).

The shells are sealed really well right out of the factory and they do perform aggressive water testing on the shells. They then add fiberglass insulation and an interior metal skin.

I would be sure to check every opening on the interior shell as well to make sure it is sealed. That also needs to be airtight.

If you are rebuilding one you also need to seal this as well as they do in the factory. Seal up every seam, every opening, install airtight sockets, etc, then test again (with water or a blower door test), making sure it’s totally airtight.

You can prolong the life of any trailer by keeping a roof on it when stationary, not driving it in the rain, moving to climates that don’t require heating or cooling (heating is usually the cause of most of the problems in RVs but in this case with metal on both sides both heating and cooling can cause condensation if there is water vapor in the walls), and showering and cooking outside.

Always keep up with your inspection and sealing on the exterior and the interior.

You can find airstreams to rent on Outdoorsy and other sites, making this an appealing option that you can “test drive”.

I do think that they are still a strong option to consider, especially for folks sensitive to chemicals and mold. With a high resale, low initial offgassing, and an expected lifetime of a few years for extreme mold reactors it can work really well.

Cost: The aluminum airstreams start at $40,000 USD for 16ft. They have many sizes all the way up to 33 ft and about $170,000 USD.

Weight: The 16 ft aluminum model weighs 2,585 lbs and the 30 ft model weighs 7,788 lbs.

Living Vehicle

A newer company making well-tolerated trailers is Living Vehicle. They use polyiso foam insulation sealed with tape in the walls. The interior is almost entirely aluminum including the cabinets.

The countertops are Corian. The flooring is sheet vinyl by Armstrong (common in trailers but fairly high in offgassing – it may not work for many but they could customize this with another option). See my list of safe flooring for trailers.

The cushions are polyurethane, countertops are zero VOC. The offgassing of the trailer in general has been reported to be very low.

This is a rare find because of the almost fully aluminum interior, no structural wood (no hidden wood in the new models for 2020, and no wood in cabinets, only in the table).

The walls are made of metal framing, metal exterior, and metal interior walls with polyiso foam on the interior side of the metal framing (with the air gap left behind, between the framing members).

The trailer also has a crawl space where the plumbing is very accessible. Even if there was a leak in the all-aluminum “basement”, it would be easy to clean up and easy to fix because of the access.

The company is open to some customization. I have spoken to them about this, if you would like help customizing the insulation, or interior materials like the flooring please get in contact.

The 2019 had wood in the floors.

Cost: The 2020 models are 29 ft and start at 200,000 USD.

Weight: They weigh in at 10,700 lbs, meaning you need a top of the line truck to tow this.

2. Fiberglass Travel Trailers

Egg-shaped campers are usually made of solid fiberglass shells (either single or double hull) that are very mold-resistant and durable.

Many sensitive people say that fiberglass takes a year (or years) to offgas, but some find it offgasses to a satisfactory level in a few days or a few weeks. It’s very individual.

This is the best design to hold up to mold.

In terms of used trailers, molded fiberglass trailers are the best bet since the walls are less likely to become moldy with time.

Though fiberglass trailers can have problems with the wood subfloor if it’s not encased and if they have carpet on the walls that can go musty or get cross-contaminated.

Oliver

The Oliver brand travel trailer is a popular trailer for mold avoiders.

I like fiberglass campers with molded fiberglass furniture like Oliver trailers. It makes for a simple, easy to clean, non-porous interior.

Very little wood is used, only in the cabinets.

They are double hull so they have a good R-value and can be winterized. The double hull overlaps at the seam, unlike Casita which is riveted at the seam.

The insulation between the hulls is polyethylene closed-cell foam, with an airgap between the hulls. There are weep holes at the bottom in between the julls, meant for condensation that forms between the hulls to drain out.

They claim R-16. The windows are dual pane.

It does not have wood products in the floor, making it one of my top choices.

It does have a ducted HVAC system that is not accessible in the floor (or rather, only partially and with great effort). They use flex ducts in the floor for the heating. AC is on the roof.

Using the propane furnace is the only way to keep the pipes from freezing when the temperatures drop below 0 C.

Oliver uses vinyl flooring but they can make you one without the vinyl floor. They can make it without the cushions, which makes it one of the best fiberglass option I have found.

Recently they have added a composting toilet option.

Many mold avoiders have done well with this brand, both brand new and used options. You can see a tour of the factory here.

Cost: They have two models, one is 18.5 ft long and starts at 50,000 USD, the larger one is 23″ 6″ and starts at $57,500 USD.

Weight: The 18 ft weighs 3,700 lbs and the 23 ft model weighs 4,900 lbs.

Casita

Casitas use a carpet and foam that is glued on to the walls and floor. At the time of writing, they would not customize one without that element.

The nylon carpet and glued on polyurethane foam provide some insulation (R 6-7) and help prevent condensation.

Despite the carpet, many mold sensitive folks have done well with this brand. It’s been a staple brand in the mold avoidance community since the beginning.

It has a simple design, single hull (nowhere for water to hide) and mostly all visible components.

The floor is wood but it is totally encased in fiberglass on all sides. In reality, there is very little wood inside, and only in the cabinet storage areas.

Casitas are made in Texas, but recent reports were that new ones arrived clear of mold and other persistent outdoor toxins.

See Bryan Rosner’s video about his initial thoughts on the Casita for mold avoidance:

Cost: Casita makes two sizes. The most basic model is 16 ft and starts at around $18,500 USD. The 17 ft starts at around $19,500 USD.

Weight: Models range from 1,970 to 2,480 lbs.

Happier Camper

Happier Camper is another company to check out as they don’t use carpet or padding on the walls and the floors are fiberglass too!

No vinyl on the floors is a rare find and will be preferable for many folks.

It’s double hull with Thinsulate in between the hulls.

The floors are composed of plastic honeycomb integrated with corrugated cardboard and fiberglass resin.

I like the modular nature of the HC1 interior. You can really simplify the interior if you need to or add the components that you need. The small units don’t include a shower but the larger ones do.

I’ve seen some problems with the first model (HC1). The friend who owns the one pictured had many problems on this unit when it was still brand new, and she claims the company took 7 months to make the repairs.

They are on the second model now in 2020 and have improved the doors and windows. I’m glad to see they have moved past the first prototype, made some changes and are still going strong.

I would like to see positive reports on the newer rendition before recommending it as the first iteration had way too many problems.

Cost: The HC1 is 10 feet and starts at about $25,000 USD, the new 2020 Traveller is 14 ft and about $40,000 USD. These are highly modular so the base cost might not cover what you need – adding a kitchenette to the HC1 brings it to almost 30K, fully loaded it’s almost 34k.

Weight: The 10 ft model is 1,100 lbs, and the 14 ft is 1,800 lbs.

Trillium by Outback

Trillium is another great brand, this one by The Outback. It is single hull, made in Canada and they have been in business for many years.

They have closed cell foam (probably polyurethane on the walls) with marine carpeting.

They were willing to build without plywood in floors but it was difficult to convince them to leave the padding off the wall.

The price is quite good (and even better for Americans because it’s in Canadian dollars).

They only have one size, but they have a couple layouts.

Cost: The 14 ft trailer, starts at about $18,000 Canadian dollars. However, you need to add on some basics, including brakes and lights. If you add those and a bathroom as well it comes to a little over 20K CAD.

Weight: About 1,450 lbs average weight.

Trillium by L’air

L’air is another Canadian company reviving the old Trillium trailer style.

Both companies have molds from the original Trillium factory in Ontario, Canada. L’air though has two sizes, the 1300 (15.5 feet) and 4500 (15.2 feet).

Their floors are a plywood core inside of the fiberglass structure – this is similar to Casita’s floors. It’s not prone to mold in my experience. There is no plywood exposed that can absorb moisture in the floor.

They have also eliminated plywood around the windows that was used as a filler to hold the windows in past models. Over time that plywood would become wet and rot. Instead the windows are completely bonded to the camper body. This eliminates the leaks that develop around the windows in older Trillium campers.

The walls are covered with foam insulation and then marine vinyl which does not absorb moisture and is easy to clean. Many would prefer this to carpet on the walls.

Cost: Starting at 26K CAD

Weight: 1300 lbs for the smaller model and 1600 lbs for the larger model.

Nest by Airstream

Airstream came out with a fiberglass model the Nest in 2018. It’s single hull.

The construction of them is not super clear, one video describes the interior walls as “flex foil” (it’s not clear what that is), then a polypropylene “fabric” layer, then an interior olefin fabric which also means polypropylene or polyethylene.

You can see the fabric is rather smooth, I like this much better than the “carpeted” walls in all the other single-hull fiberglass trailers. Though I don’t understand what the insulation is behind the plastic fabric walls.

The cushion coverings are a faux leather, I’m not sure if it’s vinyl (which offgasss quite a bit) or polyurethane (which doesn’t offgas very much). But it does look very mildew and mold resistant.

The countertops are laminate with engineered wood products used in the cabinetry. The flooring is sheet vinyl.

The heating system uses some ducting, but the AC system is the usual roof system.

There’s a full kitchen and wet bath.

Cost: The trailer comes in one size, it’s 16 ft and it’s about 43,000 USD.

Weight: 3,400 lbs.

HÉLIO Travel Trailer

The HÉLIO is not a single or double hull fiberglass shell – instead, the walls are a sandwich of fiberglass-foam-fiberglass. The insulation value is R-7.

It’s called a molded fiberglass monocoque structure and it has a solid aluminum chassis. The floor is a plywood wrapped all the way around in fiberglass.

It’s made in Quebec.

Cost: Depending on size and features, the dealers are starting them at 31K CAD in Spring 2021.

Weight of the 02 Model: 1550 lb. Length: 14 feet 2 inches long

Other Fiberglass Trailer Brands in North America

Scamp – Made in MN. Plywood or OSB floor, with fiberglass underneath but not on top. Single hull, carpet walls with Reflectix behind them. Some wood in the shell. Old Scamp trailers had vinyl headliner but newer ones have fabric headliner. Video of the factory here.

Escape – Made in British Columbia, Canada. Fiberglass single-hull with frames constructed out of steel tubing. A factory tour shows hidden wood framing in the walls. Vinyl flooring. The headliner/wall covering is vinyl laminated onto 3/8” foam, creating an R-5 insulation value.

EggCamper – Double hull. Bubble foil insulation between walls but not contiguous all around trailer (only in some parts not others). Owner Jim hurt his back and wasn’t building for a while. The website claims they will start building again.

Burro – Out of business in 2001, you may find used ones for sale.

Boler – Out of business in the 80s. You would only find very old trailers for sale.

If you need help choosing a trailer that suits your mold or chemical sensitivities you can contact me for a one-on-one consultation.

European Brands of Fiberglass Trailers (Caravans)

In Europe, the Wigmann is a good fiberglass caravan (as they call trailers there). It has a solid fiberglass shell with no seams on the outside. The construction is fiberglass-spray foam-fiberglass, airtight. I like this design a lot and have not seen this in North America. No wood, no metal. It has a 10-year warranty on water ingress.

Sealander is another European fiberglass caravan that is all fiberglass on the inside and out, exactly what I’d be looking for.

UK company Freedom Caravans has a fiberglass exterior but it is not the same as the molded fiberglass models. They have a 25-year warranty on water ingress which is very impressive. Though with a fiberglass exterior and more standard wall, condensation could be a bigger risk than leaks.

3. Wooden Teardrop Trailers

Custom Built Teardrop

A small teardrop can be made of all wood like the trailer pictured that I showcased in this post.

The main challenge here is in heating climates the metal base, metal or membrane roof, and walls are all a challenge for mold prevention.

If this style of trailer is used in heating climates, you can build up off the metal trailer to avoid condensation and mold below, a technique illustrated in this post.

With the roof, you cannot have an exterior vapour barrier (and a double vapour barrier is too risky). You would need to fill in the ceiling with 2 part spray foam or rigid foam + spray foam as outlined in the van post.

The walls can be wood that in uninsulated, that can work. If you add insulation you get into much trickier territory.

This trailer would work really well in climates where you don’t heat the interior. Either AC use or no heating or cooling would mean you don’t have these issues with the metal trailer base and roof.

If you have high humidity use mold-resistant woods like cedar.

A company that makes trailers similar to this, Homegrown Trailers, uses wool insulation, this means they have a challenge in heating climates that in my opinion cannot be overcome. I cannot see any way that this would be mold safe.

Cost: The 16 ft trailer came to $10,000 Canadian dollars in materials, the labor would be about an extra 10K. It has basic wiring, no plumbing, and a basic outdoor kitchen.

Weight: About 4,500 lbs.

DIY Teardrop

This is either a DIY kit or plans to make this wood-based teardrop trailer.

Although the main material is wood, it’s essentially a fiberglass trailer as it’s totally coated in fiberglass. This is built like a boat, and as long as all gaskets are done well this should not have moisture issues.

I have not seen this design in person however.

The kit includes the wood, cut to the right sizes, fiberglass, epoxy, and all basic parts. All surfaces inside and out are sealed with epoxy.

It comes with plenty of epoxy to coat and seal the trailer, the necessary final finish – varnish and/or paint – is sold separately.

The metal trailer is not included.

It’s not quite as simple as it looks, it takes about 250 hours to complete.

Someone with an illness related to toxicity could do some parts of the build themselves but not the fiberglass and epoxy. And probably not the varnish either. Though epoxy finishes generally come to a complete cure, so even those with moderate chemical sensitivities might do well with this option once it’s cured.

Check out their website and videos.

Cost: $2619 USD for the kit or $199 for the plans.

Weight: The shell is 250 lbs when fully outfitted and accessorized. With the trailer weight included, it will come to 500-600 lbs.

Vans and Truck Campers 

Cargo Van Conversion

Here is my post on converting vans into campers in a mold-safe way.

Anything with an exterior metal wall is inherently tricky to insulate for weather where you heat the camper.

If you don’t heat the van in any way or only use AC, this is an easy solution.

The company Innovative Spaces can build out a cargo van. I don’t have direct experience with them.

Decommissioned Ambulances

When I first saw Solona’s incredible recovery from CFS and MCS I was immediately impressed with this converted ambulance.

Looking more into how they are made, I found there are a few different ways of insulating them. I was not able to identify which company made this one.

It looks like most of them use rigid foam (polyiso) in the metal-framed walls and then use aluminum as the interior walls. Whatever they did in these walls to make them so air and vapor tight, it’s working.

This mobile home has held up really well to mold – an unusual feat in the RV world.

On top of that, it was an absolute bargain. This is the best value for your money of any of the options here. If you can find one that is as mold-safe inside as this one you have struck gold.

Solona paid around 9K CAD for her used ambulance in the video (and pictured above).

This is similar or the same construction as the old Camplites, ATC and Living Vehicle, but much less expensive. It doesn’t have a bathroom or kitchen though. In the video, Solona explains how she is making that work.

The government sells these off every so often. You might also find one that was already bought and is being resold by a private owner.

Refrigerated Trucks/Vans

Refrigerated trucks come with insulation already attached in a way that looks quite well done to me. You would want to confirm with the vendor how the installation was done.

You will also need to add air via a window or roof fan.

I like this a lot better than converting your own van because it’s such a tricky process to get the foam installed correctly. This is far easier because it’s already done for you.

For me the ambulance and the refrigerated vans would be my choice before a custom conversion.

Conventional RVs

Some mold avoiders have been using conventional RVs and trading them in if (when) they go moldy.

A few companies that some people like are:

Bigfoot – Made of fiberglass, EPS, and luan, with vinyl flooring. This does have wood in the walls. Though one person who is not that sensitive has done well with it, it’s not what I would go for.

Forest River RV Sunseeker Class C. A “Greener” RV company. Sunseeker has 1 piece fiberglass roof, aluminum frame, block foam insulation, no fabric except valances and bedspread and is “low VOC”. I really like the roof on this model.

Other Forest River brands are low VOC and slightly better construction than usual.

Coachman is also low VOC, mold avoiders have liked the Freedom Express and Apex Ultra Lite. Bryan Rosner outlined the strategy of going with Coachman and trading them in as needed. Here is his blog post and youtube video about this.

Don’t expect a traditional RV to last very long in terms of mold. Be prepared to trade that in in one or two years.

Many people cannot tolerate this level of offgassing, though the level has been improving in the last few years as more models go greener. Many are formaldehyde-free now. This is a strategy for folks who are mold sensitive and not very chemically sensitive because you have to go brand new here.

Also factor in the depreciation and loss of sales tax in this strategy.

It’s a good idea to see one of these in person before purchasing, unlike some of the custom trailers.

Tiny Homes on Wheels (THOWS)

Corinne Segura is a Building Biologist Practitioner with 7 years of experience helping others create healthy homes, including alternative homes, trailers, and shelters.

I have owned and lived in three trailers: my tiny house on wheels, a custom Camplite and a converted cargo trailer.

Did you find this post helpful? If so you can buy me a coffee to support the research behind this blog. Thank you!

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