Schlüter-Systems Ltd is frequently asked if tiles can be successfully installed on to acoustic floors.
Unfortunately, there is no definitive answer. With appropriate tiling protection some acoustic floors will accommodate tiles, but others won't.
When asked to tile onto an acoustic floor, installers should always seek specific advice relating to the individual application, before deciding whether it’s suitable to take tiles or not.
There is now a wide variety of acoustic flooring available, mainly to come into line with Building Regulations for sound and heat insulation -- some of which is suitable to tile onto with the proper materials, but some is totally unsuitable.
To put a rigid finish, such as tiles, over a surface that is very compressible, is asking for trouble: usually the grout lines would crack first, then the tiles would crack at the joints, and finally debond. However, many different types of installation are suitable for tiling onto, with appropriate tiling protection.
At the request of flooring contractors, Schlüter has carried out a number of site inspections where some acoustic flooring would take tiles with the correct protection: for instance, a chipboard floor with felt bonded to its underside acting as the acoustic barrier, batons with different types of foam, and others with acoustic matting.
With all these it would be possible to protect the tiles with a specialist uncoupling membrane, such as Schlüter-DITRA, which allows any stresses that occur between the acoustic flooring and the tiles to be neutralised evenly.
But if the flooring is too compressible, the movement under the rigid tiled surface will be too much, even for the uncoupling membrane to absorb. That's why installers should always seek specific advice about each particular application.
However, Schlüter-DITRA-SOUND was specially designed to ensure that the tiled surface is highly durable. Schlüter-DITRA-SOUND is a bonded impact sound insulation for tile coverings, made of a heavy polyethylene mat, which has an anchoring fleece laminated on both sides to bond with the tile adhesive. Schlüter-DITRA-SOUND reduces the impact sound of floor constructions (test values according to DIN EN ISO 140-8). The impact sound reduction achieved by Schlüter-DITRA-SOUND means that the impact sound perception is cut by more than half.
The transmission of noises causd by footsteps or dropped objects to adjoining or underlying rooms is referred to as impact sound transmission. The floor/ceiling structure absorbs the structure-borne noise and transmits the resulting impact sound in the form of airborne noise.
The human ear perceives impact sound that is muffled by 10dB as airbourne noise that is reduced by 50%. Impact sound (e.g., the noise generated by hard shoes) is also reflected back into the room. The effect is multiplied in the case of light constructions and hard surfaces, leading to the so-called drum roll effect. It can be completely eliminated by the high density of the heavy mat.
- The substrate must be level, ready to bear weight, and free of all substances that may weaken the bond. Any levelling must be completed prior to the installation.
- The appropriate self-adhesive edge strip should be used where the covering adjoins walls and other upright construction elements, to avoid the buildup of tensions or the formation of sound bridges.
- The thin-bed adhesive used for bonding the acoustic material must be selected to suit the substrate type. It must bond well with the substrate and mechanically set and cure in the anchoring fleece of Schlüter-DITRA-SOUND. Standard dry-set adhesives are suitable for most substrates, but do check for any incompatibility of materials.
- Apply the adhesive over the substrate with a notched 3 x 3 mm or 4 x 4 mm trowel.
- Cut Schlüter-DITRA-SOUND to size and fully embed the anchoring fleece into the applied adhesive. Immediately press the material into the adhesive with a float or roller, working in a single direction. The individual panels should be set tightly next to each other. Remove any excess adhesive.
- To avoid sound bridges, cover all joints with the self-adhesive joint covering, Schlüter-DITRA-SOUND-KB.
- Walking boards are recommended for taking material over the installed acoustic material, and to prevent it from peeling off the substrate.
- The tiles can then be installed in the normal way.