Prior to the fixing of Marmox Construction board, all traces of existing finishes should be removed back to the concrete substrate.  The floor should be level and dust free.  New concrete or screed should be well cured prior to the fixing of Marmox board. 

A good proprietary cementitious floor tile adhesive should be used following the manufacturer’s instructions.  Where the boards are to be used in conjunction with under floor heating, a flexible floor tile adhesive should be used for boards of 6mm or 10mm depth. Standard floor tile adhesive can be used for the thicker boards! Solvent based adhesives must NOT be used.

Apply the bed of adhesive to the floor using a notched trowel.  Any slight depressions in the concrete substrate will normally be taken up with the thickness of the adhesive.  Boards should be thoroughly bedded, ensuring that no voids remain beneath them.  Butt the boards close together, laid in a chequer plate fashion, like bonding brickwork. 

A waterproof joint can be made by running a bead of silicone sealant along the edge then butting the adjacent board up to it.  When the tile adhesive is dry, tape the board joints with a fibreglass reinforcing scrim tape.

When fixing to floors tiles should be a minimum of 150mm x 150mm in size and fixed using a solid bed fixing technique, ensuring no voids remain under the tiles.  Once the tile bed has hardened sufficiently, the joints between the tiles can be grouted in the usual manner.

6mm - 50mm boards can be laid onto a suitable floor tile adhesive - NOT solvent based.  Adhesive manufacturer's advice should be sought. 

Boards should be thoroughly bedded and laid in a chequer plate fashion, like bonding brickwork.  When set, the boards should be taped using a fibreglass scrim tape over the joints. 

10mm - 50mm boards can be mechanically fixed to flat and level timber floors using 15 fixings per board (i.e. fixings at 30cm centres) with stainless steel screws placing a penny washer under the head, screwed down until the washer bites into the board surface. 

Joints to be taped, as described above.  6mm boards should NOT be mechanically fixed.

For fixing Marmox Construction Boards (minimum recommended thickness 20mm) use a wall tile adhesive and follow the manufacturer's instructions. 

Either coat the existing sound wall surface or apply adhesive directly to one complete face of the board surface to a minimum thickness of 6mm.  Comb out with an 8mm x 8mm notched trowel to provide a ribbed adhesive bed.  Offer up vertically to the wall surface and bed firmly into place. 

For a waterproof finish, silicone seal the edge before butting up the next board.

Uneven wall surfaces should be battened out (follow instructions for fixing Marmox Construction Boards on timber stud walls). Offer up board vertically and level in. Use silicone sealant for waterproof joints as previously described.

Prior to skim coating with plaster, the surface of the Marmox Construction Board should first be primed using a PVA wash, applied in accordance with the adhesive manufacturer's instructions.  Only then should a plaster skim coat be applied to the wet PVA surface.