Underground home/space

Anyone out there who might know about underground homes? The pros being that you pay less for heating, but on the other side, you could become snowed in, or get a moisture problem, and it's more expensive to build. I would be interested in small structure, more like some extra room/space, to another existing home. It's not a root cellar I want, more like a proper living space.
Anyone here has any experience or suggestions? I am based in Europe, and was wondering about permissions and so on. Currently I live in Germany, but could be interested to maybe set up something in Portugal, or  some other country. I suppose the rules varies a lot depending of the location. Anyway, I'm happy to all sort of ideas and input.

I do like the idea, but there are a number of problems:
– Moisture can't be driven outside by heat. So you will need a dehumidifier in the space between the outside earth and the insulation.
– Light. Germany doesn't have a lot of light during winter. Underground this is even a bigger problem.
– Permissions… no idea. One reason for me not to stay in Germany.

I actually don't have really a problem with the lack of light, as I would see this more of a sleeping/chilling space, and I would have another structure overground for work, reading, cooking and other. But I do know that underground homes do not necessarily need to be dark, seen pics with proper underground homes with big windows etc.

Hello Lana,

Underground houses are big here, there should be many people who can give you a lot of info/ you may find more results by searching "Earth Integrated Structure," "Mike Oehler," or "Wofati."

Here's a link to an article by Paul Wheaton: Wofati - Earth Integrated Structure

and here's a link to a book download by the originator of this type of design: The $50 Underground House

I hope this helps, Happy Building! :)

Mike Oehler was really keen on having lots of light in the space, and moisture shouldn't be an issue if built properly. Paul has been making the wofati using heavier duty recycled billboards for the waterproof covering, and pond liner is also recommended over the original 6 mil poly sheeting Mike used, although that worked if it was handled carefully to avoid tears.

Using a rocket mass heater for the heat source should combine to make a very comfortable living space, and if you can afford to add a PAHS insulated umbrella layer to extend the dry, insulated soil mass further out from the structure it should do even better on needing less heating over time as the earth warms up with use and solar heating.