FAQ Manager v1.0: Floor Insulation

FAQ s


We have provided the most common Frequestly Asked Questions about insulation. If your question is not covered please contact us.: 1. Why floor insulation?; 2. What is insulating backer board ?; 3. What thickness of insulating backer board do you recommend ?; 4. What are the benefits of insulating backer board ?; 5. What if the floor level prevents the installation of insulating backer board?; 6. How do I cut insulating backer board?; 7. How do I join insulating backer boards together ?; 8. How do I fix insulating backer boards to concrete floors ?; 9. How do I fix insulating backer board to wooden floors ?; 10. How do do I waterproof the joints in insulating backer board; 11. Tile Fixing ?

1. Why floor insulation? - Top: Insulating the floor prior to laying the heating system will increase thermal efficiency, provide faster heat up time and reduce running costs.

Systems rated at 160 w/m² are installed on uninsulated concrete floors with good results both in conservatories and internal rooms. However, heat travels in both directions and due to the thermal dynamics involved, a cold uninsulated concrete subfloor will absorb up to 30% of the heat load down into the floor.

A thermal barrier between the heating and subfloor will increase performance and save money on electricity costs.
- Updated: September 19, 2005

2. What is insulating backer board ? - Top: Our insulating backer board is a construction board made of extruded polystyrene, which is totally waterproof, faced on either side with a fibreglass mesh, which is embedded into a thin cement polymer mortar. - Updated: September 19, 2005

3. What thickness of insulating backer board do you recommend ? - Top: This can be restricted by the floor level of your installation.

10mm is fine in most cases and it is our most popular size direct from stock.

The time to warm up a tiled floor will hardly be noticeable, whether you use a 10mm insulating backer board, 20mm board or thicker board.

For new floor construction, when you can plan ahead and arrange the floor levels to suit your new installation, a 50mm layer of insulation board is an option. The 50mm layer of insulation board will replace part of the floor screed and maximise the performance of the heating system.
- Updated: September 19, 2005

4. What are the benefits of insulating backer board ? - Top: Being extremely strong, our insulating backer board can be used as a structural element in the floor. It will withstand a load of 30 tonnes per square metre.

Insulating backer board will save you money by acting as a very efficient thermal barrier. It reflects the heat upwards into the tiled floor instead of allowing heat to warm up the concrete slab below.

Using insulating backer board installed directly under ThermMAT or ThermCABLE and the tiled floor, will result in a heat up time of less than 40 minutes. Without insulating backer board it could take anything up to 2-3 hours, or more.
- Updated: September 19, 2005

5. What if the floor level prevents the installation of insulating backer board? - Top: If insulating backer board is not installed there should be insulation in the subfloor to assist the performance of the heating system.

A 160 w/m² system is perfect for a warm tiled floor on uninsulated concrete subfloors, but up to 30% of the heating will be absorbed downwards into the concrete slab without a thermal barrier such as insulating backer board.
- Updated: September 19, 2005

6. How do I cut insulating backer board? - Top: With a sharp knife – Stanley knife or similar. - Updated: September 19, 2005

7. How do I join insulating backer boards together ? - Top: Butt them close together, laid in a chequer plate fashion, like bonding brickwork.

- Updated: September 19, 2005

8. How do I fix insulating backer boards to concrete floors ? - Top: Prior to the fixing of insulating backer 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 insulating backer board.

A good proprietary flexible floor tile adhesive (not solvent based) should be used for boards of 6mm or 10mm depth. 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.

A waterproof joint can be made by running a bead of silicone sealant along the edge face and butting the adjacent board up to it. When the tile adhesive is dry, tape board joints with a fibreglass reinforcing scrim tape.
- Updated: September 19, 2005

9. How do I fix insulating backer board to wooden floors ? - Top: 6mm - 50mm boards can be laid onto a suitable floor tile adhesive - NOT solvent based. Adhesive manufacturer's advice should be sought. Boards are to be thoroughly bedded and laid in a chequer plate fashion, like bonding brickwork.

When set, the boards are to 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 are NOT to be mechanically fixed.

- Updated: September 19, 2005

10. How do do I waterproof the joints in insulating backer board - Top: By laying a bead of silicone sealant along the edge of each board, so that when the adjacent board is butted up, the joint is made waterproof. - Updated: September 19, 2005

11. Tile Fixing ? - Top: 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.

- Updated: September 19, 2005