Material testing

Due to my chemical sensitivities (MCS), I had to test all the materials used for tolerance before installation. You can find the results in this article.

Tolerance is always individual. The findings do not provide any general information on indoor health or pollutants. What works for me does not necessarily mean it is ecologically friendly.

The list is far from exhaustive; unfortunately, I did not record notes for many tests. Mentioning product, manufacturer, and retailer names is not intended as advertising.

Wood

There are big differences in the natural emissions of different types of wood. The silver fir used in the interior emits only few VOCs. An overview of different types of wood can be found in this report on page 22 (it’s in German).

In the individual tolerance test, the order was roughly as follows (good to bad):

• Poplar
• Silver fir
• Beech
• Ash
• Spruce
• Douglas fir/ larch

Various treatments aim to alter wood properties. For sauna construction, there are thermally treated woods that promise extremely low VOC emissions at high temperatures. However, the tested products had a smoked odor and were not compatible for me.

Generally, long-aged wood is more compatible.

Glue

Titebond (original) was used for specific points in the framework.

Only bone glue was used for the interior. Conventional white glue or fish glue were not tolerable.

Panels

Tested were:

• Multi-layer boards (spruce, silver fir, beech, poplar): Intolerable
  • For the kitchen front and the dry separation toilet, formaldehyde-free glued 3-layer boards were used, which were sealed with a PU floor lacquer (AFM Safecoat). Next time, I might consider panels based on phenol-formaldehyde glue.
  • You can find a great overview of the boards and glues on Corinne’s blog
  • Perhaps longer-aged panels would have been tolerable
• Chipboard: Kronospan: Comparatively low emission values, but still completely intolerable
• Plywood for sauna construction (Spa-Plex): Intolerable
• High-pressure laminated boards (HPL): Better than chipboard if all joints are sealed but still not good
• Screen printing board (melamine resin): Intolerable
• Knauf Aquapanel (mineral): Intolerable

Not tested:

• Glue-free solid wood panel: GFM installation/diagonal board from Junker:
  • 3 cm thick, therefore too heavy for the tiny house
  • Made of spruce/fir
  • Not rigid, airtight possible (with foam in the groove)
    • Possible alternative: Holz100 wall

Magnesium oxide panels might be an option but are very brittle.

Wood treatment

• Linseed oil, hemp oil: not compatible even deodorized; coconut oil or olive oil are not hard-drying
• Notes on a test two weeks after application on wood (products from Purenature.de)
  • Casein marble flour paint: strong odour
  • Glued wall paint: similar to casein marble flour paint, slightly musty
  • Vega natural white clay paint: smells like old houses, slightly better than the previous two
  • Rügen chalk wall paint: Similar odour to the clay paint, but slightly stronger
• Volvox ProAqua
  • Wood stain: Well tolerated, only poorly suited for exterior use (peels off)
  • Wood varnish: Well tolerated
  • Both contain a minimal amount of isothiocyanates, no other option with water-based. From my perspective, not problematic
• For sealing intolerable materials:
  • PU lacquer: Afm Safecoat PolyureSeal BP: Not great when fresh, ok after 2-3 months
    • Strange odour when it gets wet
  • Afm Safeseal: OK after 1-2 months
• Not tested, but likely ok
  • Beeswax/carnauba wax
  • Shellac (hard to work with)
  • Potassium silicate/ water glass

Insulation

• Styrodur (brand name for XPS): no odour, made a good impression
• Sheep’s wool: Isolena: 0.0385 W/mK, needled on the surface, 18 kg/m³: well tolerated
  • Not equipped with biocides
  • Protection against insects through “plasma ion treatment“
• Unfortunately, I did not note exactly which products I tested. Intolerable/excluded are:
  • Ecose “Unifit TI 135 U” from Knauf Insulations (glass wool), 0.035 W/mK
  • Gutex
    • Thermosafe: With white glue 0.038 W/mK
    • Thermoflex: With 5% textile fibre, 6% ammonium salts, 0.036 W/mK
    • Thermosafe wd: 4% PUR resin, 0.046 W/mK
  • Pavatex
    • Pavaflex: 7% binder fibres, 8% ammonium polyphosphate, 0.038, W/mK
    • Pavatherm: 0.5% paraffin, 4% polyurea, 0.00% aqueous polymer concentrate, 0.00% flame retardant
  • Steicoflex: wood fibre, polyolefin fibre, ammonium sulphate, 0.038 W/mK
  • AFB evo from Rockwool (formaldehyde-free rock wool)
  • Perlitte fill
  • Spray foam
  • PUR
  • Cork

Windows

Wooden windows were not an option: they are glued and need regular treatment (very difficult, exception: e.g., walnut). With wood-aluminum windows, no additional treatment is necessary.

Aluminium windows have a plastic core for thermal decoupling (otherwise they get freezing cold inside in winter). The plastic core was ok, but the thick seals are a major problem:

• Between the window and the sash, there are usually two EPDM seals, one several centimeters thick in the middle, a thinner one at the edge. I removed the former (reducing airtightness, but no drafts), leaving the latter. It is not well tolerated but remains without noticeable consequences due to the otherwise good indoor environment.
• Additionally, there is a thick seal between the sash and the pane; it was replaced with a wooden strip for the new balcony door. It was essential that the seals were not glued.
• The odour of the EPDM seals persists and does not go away even after many years.

Plastic windows often use different plastics for the frame/sash. Even used, they were sometimes a bit problematic for me.

Old aluminum windows (with removed EPDM middle seal) were optimal for me, followed by used plastic windows and the converted, new aluminum balcony door.

Vapour barrier

The Intello climate membrane from pro clima was the most tolerable: the tolerability is not great, but not dramatic either.
Not using it would have had more disadvantages. The Solitex Mento from pro clima was used as the underlay.

For the vapour barriers, an aluminium foil with a PE core (Technonorm DS Alu) was well tolerated.

Tape

The system adhesive tape from pro clima Tescon Vana/Invis is ok tolerable (and by adhesive tape standards: incredibly good!).

I tolerate the aluminium adhesive tape from Purenature well.

Electrical installation

Surface-mounted sockets and light switches from various manufacturers were tested. The most compatible were those from Busch-Jäger.

The power lines are halogen-free, flexible cables. Unfortunately, I did not note the manufacturer. They are not particularly tolerable and run in closed cable channels made of galvanized sheet steel. The fuse box is standard and was sealed on the sides with aluminum tape.

Heating

Infrared panels from Elbotherm (exceptionally friendly contact!) were tested. They are made entirely of metal on the outside, the edges are slightly problematic and would probably need to be taped.

Truma gas radiators: The surface gets very hot (dust/heater odour).

Alde: The radiators are well tolerated, the EPDM sleeves for connection are not at all (were taped). The boiler itself is located in the anteroom; it would not be tolerable in the main room. The antifreeze fluid was replaced.

Water pipes

The domestic hot water installation is made of copper, short connecting pieces to the gas boiler are made of plastic (John Guest system, well tolerable).

Silicone

Ottoseal S130 (S130 fungicide-free with silver particles) and the aquarium silicone from Soudal were the most tolerable.

Paints & powder coating

Powder coatings are well tolerated by me, while paints often are not.

The facade/roof sheets from Prefa were – depending on the coating – not compatible to varying degrees.

Pigments

Powder pigments from Volvox or Casa-Natura were well tolerated.

Linoleum

Unfortunately, linoleum (Marmoleum from Forbo) was not tolerable.

Cooker

Induction cooktops always have a fan. Flame retardants are problematic for me, so a regular ceramic cooktop was installed.