The ultimate do-it-yourself project is to build a house, and it's a surprisingly widespread pursuit.

Build-your-own-house school, also called owner-builder schools, have been thriving in the northeastern United States for several years and the movement has spread to the West Coast and Midwest.

One of the best-known schools, often referred to as "the original," is the Shelter Institute in Bath, Maine, founded in 1974.

The school offers a special three-week "compressed" course in designing and building houses that includes skills workshops and tours of completed homes. The three-week course, which will be held this year in April, June, July, August and October, has tuition of $320 per person or $475 per couple.

There is also a "super-compressed" course of two weeks, which costs slightly less than the three-week course, and a 16-week course for evening and weekend students.

The institue helps students to find lodging during the course, provides day care for children, and sells books and tools.

"We get students from all over the country and even from foreign countries," a spokesman said.

For more information, write Shelter Institute at 38 Center St., Bath, Maine 04530.

Here are several other ownerbuilder schools that offer free brochures about their programs:

Cornerstones School, specializing in energy-efficient house building, 54 Cumberland St., Brunswick, Maine 04011.

Heartwood, based in a monastery overlooking the Berkshires, Johnson Road, Washington, Mass. 01235.

Owner-Builder Center -- said to be the largest of the schools and emphasizing passive-solar energy -- 1824 Fourth St., Berkeley, Calif. 94710.

Yestermorrow, which emphasizies solor-energy designs, Box 344, Warren, Vt. 05674.