Teardrops n Tiny Travel Trailers

Hello all!

Here's a post I wrote on a Facebook page a little while ago:

MCS: Multiple Chemical Sensitivity. If you suffer from MCS, it needs no further introduction. MCS is a little-understood chronic health condition that can cause allergy- and flu-like responses due to low-level exposure to environmental toxins such as mold and VOCs. When shopping for a camper, MCS can severely limit your options. Building materials such as fiberglass, plywood, carpet, laminates and oil-based wood finishes can aggravate symptoms ... When shopping, look for campers built from relatively inert materials such as aluminum, glass and ceramics. Avoid most manufactured wood goods (plywood can be an exception), petroleum-based foams and soft plastics. Look at used campers, which have off-gassed most of their VOCs. Consider finishing the interior of a camper yourself. Invest a high-quality air purifier. Don't buy any camper with any history of water leakage ...

Anyhow, I'd like to see what the collective wisdom of TNTTT can add to my piggy bank of knowledge about MCS-safe campers. I don't have specific pressing questions at this time; I'm just curious is anyone else has tackled this challenge, and if so, what worked and what didn't?

I don't have or know anyone with MCS, but I offer the following for thought.

When I built my teardrop, I went overboard in trying to make the exterior watertight. Even though I feel I did a pretty decent job in that regard, I was concerned what would happen if any water intruded into the shell. My OCD approach for that situation was to make the interior finishes "breath-able" so that any moisture intrusion would have a pathway out of the walls, floor and roof into the cabin and out of the roof vent when in storage. My walls, floor, and roof are sandwich construction.

To allow water vapor to permeate, the interior side of the floor plywood was left unfinished. It is topped with open cell foam exercise tiles, and then a mattress. The roof plywood was left unfinished too, but was covered with a light webbing of headliner adhesive followed by hull liner. The interior walls were covered in pre-finished engineered flooring. The flooring is attached by adhesive to the plywood framing, but no adhesive was used between planks, so there was a pathway for water vapor.

While I don't think I have had any water intrusion, I have noticed off-gassing of the plywood, XPS insulation, adhesives, etc. which to me means that yes the interior finishes are gas permeable. That's good news if you want to get rid of water vapor, but not good news if you have MCS. When we camp, we always have flow-through ventilation coming in a door side window and out of the vent fan regardless of hot or cold, rain or shine.

The points I hope this illustrates for someone with MCS are: 1) always have flow-through ventilation; 2) use materials that don't off-gas or off-gas as little as possible; and 3) seal the interior as best as possible to minimize or eliminate off-gassing but in doing so pay extra attention to sealing the exterior so that you don't have any issues with trapped water.