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Frequently Asked Questions

Regarding Marmox Multiboards

1) Which way up do the boards go?
It does not matter; both sides of the board are the same.

2) Is one side of the board waterproof?
No, unlike some other boards, it is the core of the board itself that is waterproof.

3) Can I tile onto the boards or do I have to prime them?
The Marmox material is ready to tile; you do not need to do anything to it.

4) How many boards do I need?
Small boards are 0.6m x 1.25m that’s three quarters of a square metre so you need to divide the area you want by three quarters and that’s the number of ‘short boards’ you require.

5) Can I put the boards directly onto floor joists?
No, although the boards can take a weight of over 40 tonnes over per square metre, they can be distorted by the point load pressure of sitting on a joist.

6) What adhesive should be used?
Use tile adhesive; the powder version rather than pre-mixed version. So that it’s the correct strength for the tiles, this will usually be the same product you will be using to fix the tiles with.
Normal tile adhesive (C1 type) can be used on walls for light to medium weight tiles and for plastering but for heavier tiles, for external use, on floors and in wet areas a ‘flexible’ version should be used; this is categorised as “C2” (or C2F) type.

7) Can plasterboard dot and dab adhesive be use?
No, plasterboard adhesive is gypsum based, Marmox boards have a cementitious skin therefore a cement based adhesive is needed.

8) Besides tile a  dhesive, can other adhesives be used?
When necessary solvent free versions of grab adhesives will work but using these non-standard adhesives may reduce the board’s hanging weight as these alternative methods have not been tested. Please always check with the adhesive manufacturer for their recommendations.

9) How do I stick Parquet flooring to Marmox?
Only non-solvent, non-water based adhesives (such as BAL Stopgap)can be used. This is because Parquet flooring is usually stuck down with solvent based adhesive which must not be used with Marmox and Marmox is usually stuck down with a water based tile adhesive which must not be used with Parquet flooring.

10) What thickness board is sufficient to make a difference to heat loss?
To meet current building regulations very thick layers are required (phone us to calculate this if necessary) however, if at least a 20mm thick Marmox multiboard is used to insulate a wall it will make a noticeable reduction to the heat loss.

11) How many washers are needed?
Without using any adhesive, a short board will need two rows of five (10) or if the board is 12.5mm or 10mm thick, three rows of four (12). A long board will require 15 fixings; three rows of five.
Used with adhesive (the dot and dab method), five fixings per short board and nine fixings per long are recommended.
On floors, tile adhesive method should be used whenever possible. If the only practical option is mechanical fixing, screws and washers should be used every 30cm – that is 15 per short board.

12) Can I apply a plaster finish to the Marmox boards?
Yes, the surface of the boards contain additives to reduce the porosity and stop the possible formation of etteringite salts which can sometimes occur when a gypsum plaster is applied to a concrete surface. The boards therefore do not need to be primed.

13) Can the boards be placed above underfloor heating?
No, the boards are insulation boards therefore they should go below the heating elements otherwise they will block the heat.

14) What is the maximum weight of tiling that Marmox boards can hold?
The unique surface structure and patented bonding of the surface to the foam core allows Marmox boards to carry much heavier tiles than other types of tile backer board. When the board is fixed to a masonry wall with a continuous bed of tile adhesive, tile weights comfortably exceed 100kg/m². All Marmox boards from 4mm to 60mm have the same maximum “hanging weight.”

15) How long are Marmox products guaranteed for?
Marmox boards and shower formers are guaranteed for 25 years.

16) Do the boards contain anything harmful to me or to the environment?
No, all Marmox products conform to current EU legislation which mean they are free of chemicals and materials which have been found in some cheap imported boards. Our boards are free of asbestos, ozone-destroying CFC and HCFC and the potential carcinogenic fire retardant HBCD.