Walk-in shower screen installation in a U channel

A walk-in screen goes in only after the wall and floor tiles are finished. Before that, the floor has to be laid to a fall, tanked and fitted with its drain, most often a linear shower drain along the wall or a single point drain.

The installation has these stages:

• Measuring the position of the channel and checking that the floor underneath is level and the wall is plumb
• Ordering made-to-measure glass if a standard kit size is not being used
• Marking the fixing holes for the channel in the floor or the wall
• Drilling with a diamond or tile bit without hammer action and filling the holes with silicone
• Screwing the U channel down and lining it up precisely
• Lifting the glass into the channel with suction lifters and locking it with wedges or gasket inserts
• Fitting a stabiliser bar to the wall or ceiling if the manufacturer requires one
• Sealing the joints between the channel and the floor and wall with sanitary silicone sealant

The glass must never touch metal inside the channel. Plastic or rubber wedge gaskets sit between the glass and the channel, holding the glass firmly and absorbing knocks. Silicone is not used here as an adhesive, only as an external seal.

With a walk-in shower, a lot is decided before the glazier ever arrives. If any of the following points is neglected, the glass cannot put it right later.

• The floor must fall towards the drain and not towards the glass, and a fall of roughly 1.5 to 2 per cent is commonly quoted
• The tanking must cover the whole shower area and run up the walls, and because the channel is fixed through it, every hole has to be sealed
• No underfloor heating pipe, water pipe or cable may run under a floor channel, and it is wise to photograph their positions before the screed goes down
• The wall beside the channel must be able to take the fixings, so a plasterboard wall needs a pattress or reinforcement fitted there in advance
• The length and position of the glass decide how much water splashes out, and with a short panel the floor in front of the shower will get wet

Walk-in screens use toughened safety glass, usually 8 or 10 mm thick. Thinner frameless glass would vibrate when touched. A fixed panel is heavy, roughly 20 to 25 kg per square metre, so two people have to hold it during fitting.

A floor U channel holds the glass from below. It is the strongest option, and the glass can then stand freely in the room with a wall fixing on one side only.

A wall U channel holds the glass from the side. The bottom edge of the glass rests on the floor on a seal or sits just above it, and the glass is usually braced with a stabiliser bar.

A combination of wall and floor channels is used for longer and taller panels, where the glass needs support on two sides.

Channels come in anodised aluminium, stainless steel or in black or brushed gold finishes. When choosing, check which glass thickness the channel is designed for, and buy the glass and the channel from the same manufacturer.

The simplest case is a short panel next to the wall with a wall channel and a stabiliser bar. More work comes from:

• A long floor channel, where many holes have to be drilled through the floor tiles and the channel set precisely level
• An L-shaped screen or two panels joined at an angle
• Walls out of plumb or a floor that is not level under the channel
• Large-format or very hard floor tiles that are difficult to drill
• Underfloor heating, where it is essential to know exactly where it is safe to drill
• Made-to-measure glass, which is produced only after the survey and extends the whole timetable

A fall towards the glass. If water runs towards the channel instead of the drain, it pushes under the glass and out into the bathroom. The fall has to be checked before tiling, because it cannot be corrected afterwards.

Drilling through the tanking or the underfloor heating. Holes without silicone let water get under the tiles. A drilled underfloor heating pipe means breaking up the floor. In practice it often happens that these mistakes only show up after several months.

Glass stuck into the channel with silicone. Silicone does not replace the wedge gaskets. The glass is then not properly locked, the silicone gives way over time and the panel starts to wobble.

No stabiliser bar. A tall panel fixed only at the side flexes when someone leans on it. If the manufacturer specifies a stabiliser, it has to be fitted.

Glass that is too thin. 6 mm glass does not belong in a frameless walk-in channel. It vibrates and the channel cannot hold it firmly enough.

Measuring before the floor is tiled. Adhesive and tiles change both the height and the width of the opening. Made-to-measure glass is surveyed only on the finished surface.

A practical homeowner with a helper, suction lifters and a drill with a tile bit can fit a walk-in panel from a kit with a wall channel. Leave long panels in a floor channel, made-to-measure glass and any fitting over underfloor heating to a professional. Always follow the manufacturer's fitting instructions.

1. Check the glass, especially the edges and corners, and make sure every part is in the box.
2. Hold the channel against the wall, set it plumb with a spirit level and mark the holes.
3. Make sure no pipe, cable or underfloor heating runs where you are going to drill.
4. Put masking tape over the drilling points and drill without hammer action.
5. Fill the holes with silicone, push in the wall plugs and screw the channel to the wall.
6. With your helper, lower the glass into the channel onto its setting blocks and never rest a glass edge on the floor tiles.
7. Lock the glass with the wedge gaskets as the instructions describe and check that it stands plumb.
8. Fit the stabiliser bar and tighten it so that it does not pull the glass to one side.
9. Seal the outside joints between the channel and the wall and floor with silicone and leave it to cure.

At handover, look over the walk-in screen and try the shower. Check that:

• The glass has no scratches or chipped edges
• The glass stands plumb and does not vibrate or wobble when pressed
• The channel is straight, firmly fixed and has no gap against the wall
• The wedge gaskets are intact and do not stick up above the channel
• The stabiliser bar is firm and does not pull the glass to one side
• Water runs to the drain during a shower and does not escape under the glass
• The silicone joints are continuous and free of gaps

Maintenance is simple: wipe the glass with a squeegee after showering and clean the channel now and then, because limescale can build up inside it. Clean the linear drain regularly, since a blocked drain sends water back across the floor towards the glass.