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"Concrete/foam block houses are efficient, strong, secure, quiet"

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Dear Jim: We are planning our "dream" house. We want it to be stylish, but also energy efficient and reasonably priced. With concerns about terrorism, its strength and airtightness are important. What do you suggest? - Jon M.

A: One of the best house construction methods, considering your particular concerns about disasters, is stay-in-place-form concrete walls. These houses are not only super energy efficient, but they are extremely strong. Even tornado or hurricane winds won't blow one down.

Other than deeper window openings, these homes look like any other. Your architect will actually have more styling flexibility due to the strength. Interior and exterior walls can be finished with drywall, paneling, siding, brick or stucco.

I would recommend one of the foam block building methods. These are large, often four-foot-long, hollow foam blocks. They are usually made of polystyrene insulating foam like a cooler. Once the blocks are stacked up to create the wall, concrete is pumped in the top to fill the hollow block cavities.

You can expect your utility bills to be about half those of a code stick-built house. This results from the high insulation level and the efficiency benefits of the high thermal mass of the concrete. The overall building cost is only about three to five percent more than a lumber stick-built house.

The first thing you notice when you enter one of these houses is how quiet it is. The heavy insulation and concrete mass inside the walls block outdoor noise. With the concrete core and tight sealing foam blocks, the homes are very airtight. This is an advantage for your terrorism concerns.

You have several choices of foam block designs. One type, called waffle, uses molded all-foam blocks with internal webs. This creates continuous cavities of various widths. If you would break away the foam insulation after the concrete sets, the concrete surface would resemble a waffle.

Another effective design is a flat wall. These blocks are made of flat sheets of foam insulation, usually about two inches thick. There are metal or plastic webs in between them to space them apart. When the concrete is poured in, it forms a core of constant thickness, often six to 12 inches.

The waffle-type blocks produce a higher overall insulation level because there is more foam. Also, less concrete volume is needed to fill the wall. Talk to builders to see which they prefer to use in your area. A third foam block design produces a post-and-beam concrete pattern inside the blocks.

There are also new foam floor/ceiling/roof insulating foam forms. Concrete is poured over them and in channels. They are very strong, efficient and quiet.

Instant Download Update Bulletin No. 746 - buyer's guide of 18 manufacturers of concrete/foam blocks showing type of foam used, dimensions and weights of blocks, finished insulating wall R-values, prices, detailed descriptions of how the blocks are assembled and many illustrations of the various block designs and assembly methods.

Dear Jim: We are working on our house to get it ready to put on the market to sell. It was built in the 1970's and has aluminum wiring. Is it necessary to replace the wiring before we sell it? - Carole P.

A: Aluminum wiring was installed in many house during that period because of copper shortages and its high price. The hazard with aluminum wiring is at the connection points where the resistance can increase and get hot.

You should check your local codes about the need to replace it when you sell a home. It is a major job to replace wiring and you will not want to tackle it yourself. It will require tearing some walls open for access.

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