Builders are using new materials and innovative construction techniques to erect houses more quickly and cheaply than ever before, but inexperienced workers and some poorly conceived products are taking their toll in quality.

Plastic plumbing pipes, aluminum wiring, vinyl-framed windows, and ceramic and metal roofing are some of the materials that have provided unpleasant surprises for new homeowners in recent years.

In the face of sharply rising costs, the home construction industry has pressed for incorporation of new materials and standards to help keep prices down and profits up. Local jurisdictions, as well as national organizations that set widely used model building codes, have responded with code changes to allow use of much new technology.

"In the last 10 years there has been much more movement in new materials and innovative products," said William J. Tangye, executive director of the Southern Building Code Congress, one of the groups establishing model codes. Builders and manufacturers want to save money and find "better uses of available resources," Tangye said. For example, builders can use 2-by-4-inch wood for frame-like trusses in roof construction instead of 2 by 6's, he said.

While many of the changes have benefitted homeowners and builders, others have caused problems.

Improperly installed plastic pipes came apart in a suburban Maryland town house recently, flooding the home below it, six months after the Washington Suburban Sanitary Commission banned the hard copper crimps on the pipes that led to the problem. A WSSC official said many more homes have the same type of plumbing work, and "it is possible those hard copper crimps were installed incorrectly, and they may separate either tomorrow or over a period of years."

Residents of the Oakvale Estates community in Silver Spring say their $160,000 homes conform to the Montgomery County building codes, but floors in many of the homes sag and bounce.

Aluminum wiring "illustrates a new product that had to go through an unfortunate field review and some careful scrutiny by inspection agencies to identify some of the field problems that could occur," according to Rick Lawson, Fairfax County's director of inspections.

Two major problems turned up that manufacturers and users did not anticipate, he said. One was the wiring's incompatibility with copper connectors and devices such as wall outlets that led to corrosion and bad connections, Lawson said. The problem was solved with connectors made of a different material that could be used safely with aluminum, he added. The second difficulty -- which was not spotted until it caused problems in homes -- was the heating and cooling of the wire when current passed through it, loosening connections. In this case also, new, safe connectors were designed, Lawson said.

The development of new pipe materials, also spurred by rising copper costs, has produced at least as much controversy as aluminum wiring. A few years ago, stainless steel was being used for pipes, but it requires a different soldering compound during installation than the copper pipes to which plumbers were accustomed. "Plumbers mistakenly used the wrong kind of dope, and it ate through the stainless steel in about 30 days," said Dwight Schar, president of NVHomes.

Then, plastic piping, most often made of polybutylene, was developed. It is allowed by most local building codes and is widely used.

Like stainless steel, the plastic is cheaper than copper. It also is simpler to use, can be installed quickly and thus saves builders money in labor costs, according to John Liebl, senior mechanical engineer for the National Association of Home Builders Research Foundation. "It has quick-connect pipe fittings that just pop together," Liebl said. "If a guy can read, there's nothing to" the installation.

Others dispute this asssessment, saying a number of things can go wrong. The pipe "can crimp if you bend it too sharply, the fittings snap on and can leak if they're not put in properly, you can drive a nail into a pipe if it's hidden and you don't see it," an industry expert said.

Some critics say local and national code setters have moved too quickly in accepting new products and standards. Several of the Oakvale residents feel they have not been well-served by their county's building code. "There's not one room in this house where you can put a record player, and walk across the room without the needle jumping on the record," said resident Norma Robertson. In the dining room, "water glasses jiggle" on the table when someone walks through the room, she said.

The joists under the floors of the Oakvale homes are within legal limits and are not unsafe, said Gene Sullenger, president of the Oakvale Community Association. "But these are $160,000 and $170,000 homes. You would assume that, when you pay that kind of money, you could walk in a room without scratching records on the record player."

"Physically, there is nothing wrong at all" with the houses, counters the builder, Douglas Noakes, president of Winchester Homes. "Whether the floor vibrates is subjective. There are certain spans in certain houses that are near the limit" allowed in the building code, but others that are above code, he added. Noakes said Winchester has built many other houses in the Washington area, using the same methods as in Oakvale, without complaint from buyers.

Robert M. Seely, acting chief of the Montgomery Division of Construction Codes Enforcement, said that the purpose of code provisions is to "protect a structure in terms of collapse and fire safety. . . . They're minimum performance codes and not consumer-related."

And "with costs being the way they are, most builders -- certainly large builders of many houses -- are going to build to the minimum" specifications allowed, Seely said.

Gluing wood products is a relatively recent technique that has become more effective with new, high-quality glues, according to Schar. Using these glues to fasten plywood to floor systems eliminates squeaking, he said. Glue also is being used to fasten the sections of support beams together, but problems occur when this technique is used. "The quality of the grading of the lumber is not quite as high-standard as it should be, and there is moisture content," he said. The wood dries out, cracks and squeaks.

While building codes have incorporated much new technology recently, they also have shifted in emphasis "to a more-performance-type language," Tangye said. For example, several years ago, a code might require a 12-inch brick or concrete party wall between row houses. Most codes now would specify a wall that would resist fire for four hours. Many codes today call for two-hour-fire-resistant walls in single-family town houses and one hour of fire resistance for party walls of condominiums.

These specifications have led to the use of drywall for party walls, especially in condominiums, because drywall with two- and one-hour-fire-resistance ratings is available now, he said. A resident of a Greenbelt condominium complex, which has party walls made of drywall, said her unit is "beautiful but almost unlivable" because of the noise from other apartments.

Defenders of new techniques and materials say they work fine when properly used, and are the only way to keep housing costs down. The problem is that many of the new materials require special installation techniques and supplies, and construction workers often do not know how to handle them, many people in the industry say.

And, with the high volume and swift pace of construction in most areas, "it is not possible for a code inspector to watch installation" of all materials, said David R. Conover, technical services director of the National Conference of States on Building Codes and Standards.

Taking time to train carpenters and other workers at construction sites is costly and slows down the work, and thus little instruction is provided, said Rick Lawson, Fairfax County director of inspections.

Industry experts say some of the problems that arise when workers don't have time or the inclination to change their ways include: Fiberboard sheathing less than a quarter of an inch thick that goes on studs before the siding of a house is applied must be nailed every few inches in a specified pattern to form a structural membrane to ensure its strength. "This was fine and dandy," said a Washington engineer. "Then I watched installation at building sites. The carpenters were nailing them like they used to nail plywood -- every couple of feet up and down the studs. So you get a lightweight wall section." New ceramic-coated metal roofing must be installed with special fasteners and must be installed just right or the roof will leak. Vinyl-covered window and door frames must be installed with sealant compatible with the material or the sealant will dissolve the vinyl.

There is general agreement that the purpose of nearly all the new standards and products is to hold down costs, but there is less agreement on whether home buyers are the major beneficiaries.

Northern Virginia Builders Association official Tony Ahuja said the savings are passed on to buyers "absolutely." But an industry critic, Al Louis Ripskis, argued that "any cost savings are rarely, if ever, passed on to the homeowners."

Fairfax County's Rick Lawson said, "In a buyer's market, the savings are passed on to the buyer. In a seller's market, they aren't."