Lessons learned: After 3 years

This post is about the experiences and mistakes made. The image shows the peeling varnish and deteriorating powder coating three years after construction.

Overall, the project was successful. The tiny house is solid, I feel very comfortable in it, it is well tolerated and there are no mold problems. However, there are significant problems, and I would do some things differently next time.

Planning

A significant challenge was testing all materials; at times, I was bedridden for a week if things went wrong. Still, back then, I did not realize that planning would be much more exhausting and time-consuming than testing and researching materials. Due to the lack of building standards and without an architect, numerous things had to be planned and considered. At times, I was extremely overloaded.

Next time, before starting construction, I would create a schedule (sequence, by when each decision must be made, and materials ordered) and plan the implementation in detail. I would also keep detailed records from the beginning for decisions, meetings, and information.

Trailer

Tip: Order leveling jacks along with it.

Floor

Next time, I would err on the side of caution with the floor structure and plan for increased moisture release by incorporating cutouts in the 3-layer floor plate.

Climate membrane

The Intello Plus from pro clima was ordered but the regular Intello (without additional reinforcement) was delivered and installed.

Facade & constructive tightness

The varnish (Volvox ProAqua) on the wooden facade peels off and needs to be renewed every year. Finding compatible alternatives has been a huge effort, and unfortunately, none were found. In retrospect, I would have preferred to focus more on structural integrity without maintenance requirements for the exterior. This was successful in the bathroom and for the roof; next time, I would plan the entire facade (including reveals) in aluminum. The wooden window reveals on the sides without a roof overhang could have been somewhat protected with folded metal sheets without much effort.

Instead of silver fir, spruce was delivered, so part of the facade is made of spruce. The powder coating is peeling off on many of the sheets, and on one sheet it is peeling off completely (manufacturing defect). They need to be recoated.

The vents stamped into the aluminum sheets for ventilation would not be necessary with the current construction. Normal ventilation with a suspended facade would also be possible. This would optimize the roof ventilation, as there would be a greater height difference between the openings on the longitudinal sides (under the gutter/ventilation slots).

Behind the vents is a fine mesh (insect protection), but the roof ventilation under the gutter is not protected (maximum opening about 6 mm). In combination, this makes no sense.

Room layout

The room layout has worked very well. I’m still not convinced by the typical tiny house sleeping area in the loft (headroom) and, depending on my state of health, I often wouldn’t be able to get up the ladder anyway. However, a elevated ceiling above the bed would be great to enable the installation of a lift bed. A seating area could then fit underneath.

Only the kitchen and the desk are built-in, so I am flexible in space usage. I prefer to avoid too many built-in cabinets (as in a caravan) to maintain an open spatial impression.

The large entrance area is great. Even without the chemical sensitivities (MCS), a storage room is incredibly convenient, and I would not skimp on space here.

It is very bright but not too exposed. The number, size, and orientation of the windows are just right for me. Outward-opening windows would be a bonus.

Heating

After 1.5 years, the hot water boiler of the heating system (Alde 3020 HE) defect and water leaked from the housing. Fortunately, no major water damage occurred. In forums, others had the same problem; presumably, a weld seam was broken (material defect). The boiler is made of stainless steel, so corrosion could not be the cause.

The heating circuit, on the other hand, is made entirely of aluminum, shows (as of 2023) extreme pitting corrosion and must be replaced in the coming years. The cause is three brass sleeves that I ordered by mistake and whose copper ions are causing the funnel-shaped pitting corrosion.

Next time, I would prefer not to use (camping) special solutions and rely as much as possible on conventional solutions/home technology.

Ventilation system

Despite the exhaust fan running continuously at a high level in winter, the humidity is high. The fan is relatively loud. Next time, despite the high space requirements, I would choose a ventilation system with a cross-flow heat exchanger and activated carbon filter. There are no suitable ready-made systems, so a lot of planning and development effort would be necessary. For the next winter, I would also like to purchase a dehumidifier additionally.

The MCS is now better, so a normal extractor hood above the stove would be possible. In retrospect, however, the decision to install a downward-opening window above the stove was the right one.

Shower

The shower is small (shower tray 68 x 76 cm), but big enough to not feel cramped. However, the threshold should be slightly higher, sometimes a few splashes of water end up outside.

The custom-made tub has no slope, so water must always be pushed towards the drain after showering. It doesn’t bother me.

Waste water

Presumably, this is obvious to everyone but me: insulate wastewater pipes. After a few days with double-digit subzero temperatures, my wastewater froze once. Now it is insulated.

Double protection

In all places where a malfunction/defect could have catastrophic consequences, I am now a fan of redundancy. For example, I would waterproof the walls in the niche with the heating installation and washing machine and install a tub with a drain underneath. Alternatively/additionally, a water detector with a shut-off valve in the supply line would be a good option. The facade membrane secures the insulation, next time I would not do without a roof underlay under the roof despite my intolerances.

Mishaps

I accidentally ordered Ottoseal S 100 silicone (fungicide-equipped) instead of S 130 (without fungicide equipment). Fortunately, Martin noticed the mistake before installation.

It showed me again how much can actually go wrong—and in hindsight, that the construction was successful despite everything.