How to Design an Underground House

An underground house offers significant advantages over a conventional above-ground home. It requires no air conditioning and is very cheap to heat. Underground houses are also largely fireproof and have effective natural soundproofing against outside noise. Another plus is that you never have to reshingle the roof (though you may have to mow it, depending on what you plant on top). However, because underground homes are unconventional, each one must be custom-designed, and certain aspects of the construction can be more difficult and expensive than in conventional homes. Therefore, if you want to build one, a great deal of research and planning is necessary.

Difficulty:

Moderately Challenging

Instructions

1. Choose an appropriate piece of land. One of the most common and successful underground home styles is built into a hill or slope. This allows the front of the home to be exposed to the outside and covered with windows. The sides of mountains are a popular choice for this style of home. If you intend to build on flat land, then the open courtyard style is more appropriate. This style involves building the underground home around the outside of a courtyard that is open to the sky above. This results in a structure reminiscent of a cloister.

2. Consider the terrain. It is very important that the land not be in a flood plane and that it be well-drained. It is also important that the land not be extremely rocky. Otherwise, it will be necessary to do blasting to dig the hole into which your house will fit.

3. Ensure that there is good road access to your property and that construction equipment can easily access the building site. This is of particular concern if your lot is on a steep slope.

4. Decide on the basic materials you will use for the floor, walls and roof of your home. Poured, steel-reinforced concrete is an effective and long-lasting choice. Bituthene waterproofing should be applied to the outer walls of the house before it is covered with dirt. This will prevent water from leaking through the walls and into your home.

5. Pour concrete during nonwinter months. If the temperature goes below freezing before it is dry, there will be major problems. Insist that accelerator NOT be used in the concrete since this will corrode the steel rebar.

6. Include in your design a way to bring in wiring, water lines, ventilation ducts and skylights. Unlike a conventional home, it is difficult or impossible to come back later and drill holes in the walls, since the house will be underneath the ground.

7. Hire contractors who have worked on underground homes before, so that they understand the specific problems involved. Take special care to coordinate the work of your contractors so that tasks are accomplished in an order that does not impede the accomplishment of other necessary tasks.

8. Drain the floor thoroughly before pouring concrete. There should be a base of 4 to 6 inches of gravel, followed by a vapor barrier, underneath the concrete. Use 3,000 lb. concrete mix reinforced with steel mesh.

9. Ensure that concrete forms are strong enough to hold the concrete. These should be over-engineered. If they fail, you stand to lose your entire investment.

10. Plant grass as soon as possible after putting dirt on the roof to prevent erosion. Also plan for the roof to have proper drainage so that water does not collect.

Tips & Warnings

• If you build skylights, have a way to close them at night for privacy, since anyone can potentially walk over your roof at night.

• Skylights should be strong enough to hold the weight of a full-grown man. Animals and children might climb on them. There should also be a barrier across the front of the roof so that no one can fall over.

• There are some concerns that radon gas can reach dangerous levels in some underground homes.