TN 16.23 Tiling to Gypsum Plaster Walls

INTRODUCTION
Plaster is a material commonly used to create smooth wall surfaces suitable for receiving decorative finishes such as wallpaper, paint and tiles.
Plaster backgrounds that are to receive tiles are usually based on gypsum building plasters and should be in accordance with BS 8481 and conform to BS EN 13279-1. Proprietary materials should be used in accordance with the manufacturer’s instructions. The plasterwork should be carried out in accordance with the recommendations given in BS EN 13914-2.
Plaster can support a maximum weight of 20 kg/m² so care must be taken regarding the weight of any tiles to be fixed to it. (NOTE - the weight of the tile adhesive and grout alone may be 3 - 5kg/m²).
Plaster is not a suitable background for natural stone tiles (BS 5385-1: 2018).
SURFACE PREPARATION
- Tiles should be fixed only to the finish coat and should not be fixed directly to the backing coat.
- New plasterwork should have been completed at least four weeks previously and should be dry throughout before tiling commences.
- Walls should be clean, dry, smooth and sound.
- Ensure that the plaster is free from dust, laitance and friable material.
- If plaster is shiny or polished, brush thoroughly with a stiff bristled brush.
- Ensure all movement joints are located following recommendations given in BS 5385-1: 2018.
N.B. Gypsum plaster is suitable for most internal wall tiling applications but should not be used in wet areas unless additional protection in the form of a waterproofing tanking system is used.
TANKING
In wet areas (or where potentially required), suitably prepared plaster should be waterproofed/tanked prior to tiling.
Suitable tanking kits include:
- BAL TANK-IT
- BAL WATERPROOF 1C
Please see relevant Product Data Sheets for further information.
N.B. Showers should not be brought into service for at least 14 days after the completion of grouting and sealing.

ADHESIVES
▪ For porous-bodied tiles up to 300mm x 300mm, a ready mixed adhesive such as BAL WHITE STAR PLUS may be used. If required, prime first with one coat of BAL PRIME APD (diluted 1:1 with clean water).
N.B. If BAL WHITE STAR PLUS is used on a primed or tanked background, drying times will be extended. The adhesive should be allowed to dry for a minimum of 3 days before grouting.
▪ For large format porous-bodied tiles (larger than 300mm x 300mm) and porcelain tiles, prime with 2 undiluted coats of BAL PRIME APD (second coat applied at right angles to the first, once dry). Tiles should then be fixed using a suitable cement-based adhesive (e.g. BAL FLEX ONE or BAL RAPID FLEX ONE).
N.B. If tanking is to be carried out, initial priming may not be required – please refer to the relevant tanking instructions.
COVERAGE
Tiles with a surface area of less than 0.1 m2, but which weigh more per square metre than 70% of the background’s capacity to carry the weight, should be solidly bedded. For example: - The maximum weight of tile that can be supported by Gypsum plaster is 20 kg/m².
- A 9 mm thick porcelain tile (approximately 18 kg/m2) is more than 70% of 20 kg/m² (14 kg /m²). Therefore, they should be solidly bedded regardless of their size.
GROUTS
▪ BAL GROUT FLEX
▪ BAL MICROMAX3 ECO
▪ BAL ABSOLUTE GROUT
TECHNICAL ADVISORY SERVICE
For free expert guidance on the use of BAL products, or any aspect of ceramic tiling with BAL products, contact the BAL TECHNICAL ADVISORY SERVICE on 01782 591120.
THE BAL 25 YEAR GUARANTEE
BAL products are supplied with a 25 year product guarantee. For further details and/or copies please contact the Company’s marketing department.

NOTE
The customer must verify the suitability of any information, opinion, recommendation or advice (“information”) provided by the Company for the particular application for which any goods are intended to be used and the Company accepts no liability (whether in contract, tort or otherwise) whatsoever for any loss, damage or expense arising from the misuse of any information it supplies, nor for the use of any information in or for applications which are unsuitable or inappropriate. Building Adhesives Ltd operates a continuous research and development programme and reserves the right to alter or to update information from time to time.

“Note: Any advice, opinion or information is given to assist the use of the Company’s products on the basis that the user will ensure its suitability for the application intended. In particular the Company cannot accept liability for loss or damage which may arise from incorrect use of its products or from poor workmanship. The Company operates a continuous research and development programme and reserves the right to update information without notice.”