Wall and ceiling finishes

9.2

9.2.5Ceramic wall tiling

Ceramic wall tiling shall provide a surface adequate for its location and intended use (including appearance and durability).

Where a fixed shower or showerhead fixing is provided over a bath, at a height that will permit persons to stand under it:

  • a screen or other suitable means of containing the water should be provided
  • surfaces which will become regularly wetted should be tiled or have an appropriate alternative water-resistant finish.

Backing surfaces for tiling should:

  • be in accordance with Table 9 and BS 8212
  • be strong enough to support the weight of the adhesive and tiling (where separate coats are used, they should be well bonded)
  • provide an adequate mechanical key
  • be sufficiently even to achieve an even and plane tiled surface
  • provide adequate and reasonably consistent suction
  • be rigid and stable to avoid differential movement; where this may occur, precautions should be taken, e.g. metal lathing or wire netting fixed across junctions
  • be moisture resistant, where designed for wetting to occur
  • be dry, clean and free from laitance, grease, loose material or any substance likely to affect the bond or finish
  • be reasonably even (i.e. not have gaps greater than 3mm for thin bed adhesives or 6mm for thick bed adhesives, when using a 2m straight edge).

Where the backing surface contains soluble salts, and where cement mortar is used as an adhesive, precautions should be taken, such as the use of mortar with sulfate-resisting cement.

Gypsum plasters should not be used where:

  • repeated or persistent heating occurs, e.g. on flues or near heat sources
  • repeated or persistent wetting may occur.

Backgrounds may be improved by:

  • raking out masonry joints
  • hacking and scratching
  • applying a bonding agent (particularly on very smooth and dense surfaces).

Tiles should be appropriate for their location and intended use. When specifying tiles, consideration should be given to:

  • surface finish
  • size and thickness
  • colour
  • edge shape
  • fittings (coves, skirtings, etc.)
  • accessories (soap tray, paper holder, hooks, etc.).

Tiles should be:

  • fixed in accordance with manufacturers’ instructions
  • suitable for the location, intended use and background; their weight on lightweight plaster should not exceed 20kg/m2
  • fixed according to the background, using cement mortar or proprietary adhesive
  • solidly bedded in water-resistant adhesive on a moisture-resistant background, where frequent wetting occurs.

Table 10: Standards for tiling

BS EN 14411‘Ceramic tiles. Definition, classification, characteristics, assessment and verification of constancy of performance and marking’.
BS EN 12004‘Adhesives for ceramic tiles’.
BS EN 13888‘Grouts for tiles. Requirements, evaluation of conformity, classification and designation’.

When tiling:

  • courses should be straight and even to form a plane and regular surface, especially around fittings and fixtures
  • there should be no cut or unfinished tiles at exposed edges or external corners
  • joints should be even and cut neatly
  • spacing should be sufficient to allow for expansion
  • up to sanitary fittings and fixings, the sealing method should be in accordance with the design and account for movement
  • proprietary water-resistant grouting should be used in accordance with the manufacturer’s recommendations.

Appropriately designed movement joints should be:

  • built into tiling at centres at a maximum of 4.5m, vertically and horizontally
  • provided at vertical corners in large tiled areas
  • located at junctions where there are variations in surfaces or backgrounds
  • 1-2mm where tiles are without spacer lugs.

Grouting should be:

  • as specified in the design, including mix and colour
  • cement-based epoxy resin or a proprietary product
  • waterproof in and around shower enclosures and where tiling can be saturated.