Gone are the days when bathrooms were cramped, no-frills spaces with a simple toilet, sink and standard-size tub/shower combination. Today's homeowners want spa-like bathrooms that offer beauty as well as function. One of the emerging trends is the stand-alone shower enclosure with crystal-clear glass that shows off the elegant fixtures and rich materials of the shower, such as marble, soapstone and granite.

Unfortunately, many people don't realize that ordinary glass is porous. When hard water, soap and even household cleaners are combined with the heat and humidity typical of shower environments, glass can corrode and no amount of scrubbing will remove the staining and scale that result.

One remedy that homeowners can turn to is spray-on or wipe-on treatments to protect the glass. But when these coatings wear off, staining, streaking and corrosion can occur. Another solution, ShowerGuard? glass from Guardian Industries, uses a patented ion beam technology to permanently seal the surface of the glass during manufacturing. With this new product, there is never a need to reapply the protection and the appearance can be maintained with a soft cloth or wet sponge and most common household cleaners.

If you're in the market for a shower enclosure, here are tips on what to ask the bath dealer or the professionals handling your remodeling project:

? Is the shower glass protected? First, ask if the surface of the shower glass has a sealant or other protective treatment. Standard glass can become streaked and stained quickly.

? When and how is the sealant applied? If the shower glass is protected, find out what type of sealant is used and when it is applied. Some glass coatings are applied after the glass is manufactured, which could result in their wearing off in a relatively short period of time.

? Are there special cleaners that must be used? Some glass treatments require special cleaners and techniques rather than ordinary household cleaners.

? How long will the protection last? Some spray-on or wipe-on glass treatments can cease to protect the glass after two or three years and reapplication can be messy.