– It usually grows on stumps and old trees, the fact that it now grows on the walls of houses is new, explains Kolbjørn Mohn Jenssen, managing director of Mycoteam.

He talks about wood clams, a fungus that can wreak havoc in the house where it grows.

And the fungus grows particularly well in new homes, especially modern functional homes.

Good conditions in the sun wall

According to Jenssen, the company has received inquiries from distraught homeowners who say their house is nearly collapsing from the clams.

– But why is it precisely on houses of modern construction that the fungus grows particularly well?

– Houses without eaves and the use of large timber materials allow both humidification and moisture to stay in the materials longer, says Jenssen.

A paradox is that non-toxic and environmentally friendly materials also provide opportunities for fungal growth, according to Jenssen,

– A very bad sign

– Molds seem to grow best on wooden materials on siding or other areas exposed to the weather, says Daniel Skyrud Danielsen, mycologist and claims adjuster at Norsk Hussopp Forsikring:

The fungus grows naturally on stumps and materials on open felling areas, and materials exposed to the sun on a wall provide similar and good growing conditions, experts say.

– A lot of sun and heat cause the wood to crack and the possibility of moistening the wood material. The wood clam can withstand high heat and thrives when the wood material is moistened, Jenssen says.

Check the house now!

Increases the risk of mycosis

Once the moss has started to grow on the exterior wall, you don’t have to worry about it seeping into the house as it thrives in materials exposed to the weather.

– But it can cause significant damage to roof structures if moisture penetrates the insulated roof. The high temperature you get in a roof structure makes it flare up nicely, Jenssen explains further.

– Should we instead design and build new houses in a different way that makes them more protected against clams?

– Constructive protection is an important good principle for keeping materials dry – and dry wood does not rot, Jenssen replies.

We then speak of sealing in two stages; good fit solutions and to avoid unfortunate joints.

– Good constructive protection includes, for example, roof springs that prevent a high moisture load on the facade, water panels with drops and sufficient distance to finish timbers on the cladding, explains Danielsen and adds :

– As well as the use of impregnated materials.

Pay attention to this

Removal and prevention of wood molds

– To get rid of the wood mold, it is necessary to replace the attacked wood and to stop the contribution of moisture, underlines Danielsen.

If you’ve had problems with wood clams and the resulting rot damage, and you haven’t addressed the cause of the attack, the problem may reoccur, he warns.

– Preventing wood mold and all other fungi that cause rot damage is mainly about keeping the construction dry. Houses always need good maintenance, says Jenssen.

And for new buildings:

– Remember that the weather is getting wetter and wilder, the winter is getting rainier, your home is more environmentally friendly – and good insulation prevents heat loss; that’s good, but colder facades are wet longer. The answer to all this is better constructive protection, the expert points out before adding:

– Also be aware that if your house has a good view, it receives that much more driving rain from wind and precipitation.