Norcros Pro Board fixing instructions

Fixing to Wooden Floors
By Adhesive Norcros Pro Boards may be laid using Norcros Rapid Porcelain Grey Adhesive – solvent based or ready mixed adhesives MUST NOT be used. Boards should be thoroughly bedded and laid in a chequer plate fashion making sure that there are no air gaps between the boards.

By Mechanical Fixing Norcros Pro Boards can be installed using mechanical fixings to flat and level timber floors using approximately 12 fixings per 1200mm x 600mm board-fix using Norcros 35mm diameter fixing washers and suitable screws.


Fixing to Concrete Floors
Prior to fixing the Norcros Pro Boards, all traces of loose material should be removed back to the concrete substrate. The floor should be level and dust free. We recommend sealing the floor with a suitable water resistant primer before the boards are laid. New concrete or screed should be correctly cured prior to fixing the boards. The boards can be fixed using Norcros Rapid Porcelain Grey Adhesive – SOLVENT BASED OR READY MIXED ADHESIVES MUST NOT BE USED. Apply a bed of adhesive to the floor using an 8mm square notched tiling trowel. Norcros Pro Boards should be thoroughly bedded into the adhesive and laid in a chequer plate fashion ensuring that no voids remain beneath them. DO NOT ALLOW THE ADHESIVE TO FORM A DRY SKIN PRIOR TO BONDING THE BOARDS. Any slight depressions in the concrete floor will normally be taken up with the thickness of the adhesive.

Expansion/Movement Joints
Norcros Pro Boards must not bridge expansion/movement joints in the subfloor. The integrity of such joints should be maintained through the board and tile bed and should be sealed in the appropriate manner.

Tile choice for Floors
When choosing tiles for your floor it is important to consider point loading. Applying larger tiles improves the board’s resistance to concentrated loads. For areas that may be subject to concentrated loads over 0.15 N/mm² advice should be sought to determine suitability. All tiles must be fixed using a solid bed of adhesive ensuring no voids remain under the tiles. Tiles should be fixed using either Norcros Rapid Porcelain Grey, Norcros Rapid Porcelain & Stone White or Norcros Thick Bed Porcelain & Stone adhesive SOLVENT BASED OR READY MIXED ADHESIVES MUST NOT BE USED. The chart below shows resistance to concentrated loads based on 0.15 N/mm² over a range of standard tile sizes.

Tile size examples

300mm x 200mm

150mm x 150mm

100mm x 100mm

50mm x 50mm

Load resistance over tile surface





Tile Fixing to Floors with Under Floor Heating Cable/Mat
Tiles can be laid directly on top of the under floor heating cable/mats, however care must be taken not to damage the heating cable. We therefore recommend that the heating cables are encapsulated in a bed of either Norcros Pro 50 or Norcros 2 Part Levelling Compound prior to fixing tiles. Tiles may be fixed once the levelling compound has fully cured.

Fixing to Brick/Block Walls
Make sure that the existing wall surface is sound and free of dust and grease. If the wall has a finished plaster surface and is in a good condition, it may be possible to adhere the Norcros Pro Boards without removing the existing plaster, however professional advice on the stability of the wall structure should be sought. Plastered walls MUST be sealed with a neat application of Norcros Prime Bond prior to fixing boards. Norcros Pro Boards should be fixed to walls using Norcros Rapid Porcelain Grey Adhesive. Wherever possible we recommend that the boards are bonded to the wall using a solid bed of adhesive in a similar fashion to fixing tiles. If a Dot and Dab method is preferred, the adhesive dabs must be applied directly to the board. We recommend applying a solid bed of adhesive around the edges of each board with centre dots at a maximum of 300mm centres. To avoid adhesive shrinkage, the adhesive dabs should be no thicker than 30mm. Offer up the board vertically to the wall surface and bed firmly into place. When using a Dot and Dab method we recommend securing the boards using mechanical fasteners (dowels) once the adhesive has set. Mechanical fasteners should be positioned around the perimeter of the boards at a maximum of 600mm centres e.g. for a 2400mm x 600mm board use 5 fasteners down each edge. Tape all joints using either Norcros self-adhesive alkaline resistant tape or Norcros waterproof tape

Fixing to Stud Partition Walls
6mm boards are not suitable for fixing to stud walls. For 10mm and 12.5mm thick boards, vertical studs should be set at *300mm centres. For board thickness of 20mm and above *400mm centres are suitable. All board edges must be supported by timber noggins and fixed using approximately 12 fixings for a 1200mm x 600mm board. Norcros 35mm diameter washers must be used under the head of a steel screw. Screw down until the washer bites into the board. Tape all joints using either Norcros self-adhesive alkaline resistant tape or Norcros waterproof tape (*Stud centres should be set subject to load requirement)

Tile Fixing to Walls
Once the adhesive for securing the boards has hardened and all joints have been taped, tiles can then be fixed directly to the board surface.

Prior to skim coating with plaster, the surface of the Norcros Pro Boards should first be sealed using a neat application of Norcros Prime Bond.
Note: Norcros Pro Boards must be stored flat at all times, leaning the boards against a wall can cause them to warp slightly prior to installation. If this occurs they can be straightened by applying a minimal amount of hand pressure. This correction will not affect the performance of the boards. When fixing boards in conditions where the room temperature can fluctuate considerably (e.g. conservatories) it is advisable to control the room temperature allowing the adhesive used to set properly.
All information is given as guidance and if adhered to will perform as intended. We fully guarantee the quality of our boards but as we do not have knowledge of site conditions or the capability of the installer, we cannot accept liability for damage which may arise as a result of installation. Please contact your supplier if you require further information.

Download How To Guide

Other How To's

How To

How to Grout Mosaic Tiles

How to Grout Mosaic Tiles We collaborated with House of Mosaics to create this simple step by step informative guide to grouting mosaic tiles. What is Grout? Grout is a type of mortar that fills in the gaps between tiles. This prevents moisture and dirt from getting between and behind the tiles. Grout also gives your entire […]

How To

Resilient Flooring to Anhydrite Screeds Incorporating Underfloor Heating

Description Sometimes referred to as a calcium sulphate, gypsum-based or flow screed, anhydrite screeds are a mix of fine and coarse aggregates, with a calcium sulphate (gypsum) or calcium sulphate dehydrate binder which are designed to provide a level surface ready to receive a resilient or engineered wood finish. They have a fluid consistency and […]

Technical Support

For technical information about Norcros Adhesive products please call:

01782 524140

Technical Support

Technical Support

For technical information about Norcros Adhesive products please call: 01782 524140


CPD videos

View videosContinuous professional development videos