When it's a simple question of damage from freeze-thaw cycles at an unheated cottage, none of the materials you've been investigating should give you trouble, says Dennis Atchison, purchasing manager for Crane Plumbing Corp. in Stratford, Ont. (We're assuming that you'll be conscientious about draining your water system for winter and putting plumbing antifreeze in traps and toilet bowls.)

There are other reasons for choosing one material over another, however. So-called acrylic shower stalls and tubs are the most durable and the easiest to maintain. They're actually a combination of materials. A sheet of acrylic is shaped on a form and becomes the smooth, hard surface you see and feel, while the backside is reinforced and typically finished with sprayed-on fibreglass for added stability.

Less-expensive fibreglass showers and tubs are made the same way as fibreglass boat hulls: Gelcoat is sprayed into a mould first, followed by the fibreglass and resins that create the rigid structure. There's no reason these should crack if they're correctly supported when they're installed. But the gelcoat is more fragile than the acrylic surface, and will accumulate scratches the way your boat does.

As to toilets, if you're installing a conventional flush toilet your choices are simple: vitreous china (recommended) or lower-quality clay. Again, the issue is durability and ease of maintenance, and china tops clay in both.

Since they're becoming mandatory in many jurisdictions to help conserve water, you'll probably be installing a low-volume toilet. These are notoriously balky about flushing down the "brown." Atchison suggests you look for one of the newer low-volume toilets, which has a fully glazed vitreous china surface throughout the trap (unlike older ones where the surface is unfinished beyond the bowl). The smoother surface does a much better job of flushing things the first time around.

As a final check, we took your questions to John Etienne, senior sales rep for Craig Plumbing Centre in Thunder Bay, Ont. "The deciding factor in whether bathroom fittings will stand up to winter is the stability of the building they're in," he says. A proper frost-proof foundation for your new addition is essential, because most bathroom fittings are attached to the walls, and if the walls shift from frost heaving, the best-made fittings could crack.