The most obvious wet area in your home is the bathroom and waterproofing is essential.

The waterproofing system for your bathroom or shower must meet building regulations. What system you use depends on the flooring material, whether there is a hob and the layout of the room.

You'll need a waterproof membrane that is flexible, guaranteed for 20-25 years, and chemically resistant. Some showers never dry out, so it must withstand being permanently wet.

Bathrooms
Waterproofing is best done by a professional, who will provide the necessary certificates and guarantees. In most bathrooms the joint between the wall and the floor needs to be sealed with a flexible, right-angled flashing fixed to the floor.

Don't forget timber-framed and sheeted floors need waterproofing.

Showers
Showers, especially if they're fully tiled recesses, are the weak link in the waterproofing chain. Preformed and prefinished shower bases have few problems. If there's a leak, check all the timber architraves and door jambs for rot and steel jambs for rust. Check if there is rotted timber behind the wall linings.

Shower trays

Internal trays are usually put in over the hob and out onto the floor as well as inside the shower. They're good if you're renovating an existing bathroom.

External shower trays are normally preformed in folded copper or heavy-duty PVC. They're designed to be installed before the hob is put inside the tray.

For renovators, it pays to install a new one or replace an existing one that could get damaged when tiles are removed. Treating a leak after tiling is not always reliable or possible.

Hobless showers
Fashionable, yes, but hobless showers increase the risk of damp. A brass or aluminium angle must be fixed to the floor under the shower screen, finishing at the height of the tiling. The bathroom floor must have a waste in the shower and another outside. (See picture at top. )

Floor safety
Make sure glazed ceramic tiles are textured and non-slip. Tiles that look non-slip when dry are often slippery when wet. Never use wall tiles on a floor.

Tiling around baths and basins
Water will leak behind a bath or basin unless the top rim is well sealed. In a new bathroom, wall linings are put in to overlap the rim of the bath, and the joint sealed with a flexible silicone sealant. With existing tiles, use the same sealant.

Source: Tiling (Murdoch Books)