A high quality thermal barrier will slow the process of heat loss into the sub-floor, significantly improving the performance, speeding the initial warm up times and reducing the electricity costs.

Tile backer boards (also known as construction boards) consist of an inner sheet of insulation coated with a reinforced, cementitious outer face to give them extra rigidity. This extra rigidity allows tile backer boards to be used as wallboards to tile on, especially suited for wet situations. When used for floor insulation and underfloor heating applications this outer cement polymer coating is entirely unnecessary, reducing the insulation property of the board and will not add any extra strength (the strength is in the cell structure composition of the inner insulation). For a typical 10mm tile backer board there is only 8mm of insulation!

Extruded polystyrene foams will give the best all round performance. Polystyrene has high thermal insulation properties, high compressive strength capable of supporting long-term static loading, waterproof, rot resistant, lightweight, easy to handle, easy to cut and shape with a sharp knife.

Fastwarm® insulation boards are manufactured from extruded polystyrene foam, produced without the use of CFC or HCFC blowing agents, have zero ODP and are fully recyclable. Designed to meet the very specific needs of the under-floor heating industry: extremely thermally efficient and ultra strong, suitable for electric cable installations or hot water systems, available in various depths from 10 mm to 60 mm.

Fastwarm® boards are designed to meet the very rigorous needs to be both high thermal performance and high compressive strength (30 tonnes per m2) capable of withstanding long-term static loads.

Due to it's inherent strength Fastwarm® insulation boards can be used in most situations where there is only limited room for the screed.

Fastwarm® insulation boards have approximately double the compressive strength characteristics of standard building insulation boards.

A simple rule of thumb is to incorporate as much insulation wherever possible. For new build projects this is easy to plan but in a typical refurbish situation this is not always possible where the finished floor height may restrict the depth available to add the insulation.

Fastwarm® boards are available from 10 mm to 60 mm.

For cement sub-floors Fastwarm® boards will readily bond to any good quality fast setting, water based (solvent-free) floor tile adhesive.

For wood floors care must be taken to ensure that the floor is firmly fixed to the joists, following the recommended 300 mm screwed centres as a guide, prior to applying the flexible floor tile adhesive and bonding the Fastwarm boards.

Yes, for cement sub-floors a fast setting flexible floor tile adhesive will be required. The special polymers added to flexible adhesives will make allowances for any tile floor movements through heat expansion and contraction.

Don't forget to also add a flexible grout to your list.

This depends on a number of factors like the sub-floor type and insulation: a cement sub-floor will be slow to warm without a thermal barrier, creating a significant drag on the performance of the floor. A layer of high quality insulation will have a dramatic effect in these circumstances, speeding up the initial warm up times to within 15-20 minutes.

Where normal foot traffic is anticipated Fastwarm® insulation boards can be tiled without any special preparation, using any good quality flexible floor tile adhesive.

Even without under-floor heating these tiles will be warmer as a result.

Traditional use of plywood is a well-proven method but it is difficult to cut around complicated bathroom objects, is heavy and relatively expensive; it will require fixing to the sub-floor and primed prior to the use of tile adhesive.

Fastwarm® insulation boards will achieve the same result being easy to cut with a sharp knife, available in more manageable sizes, very light weight, completely water and rot resistant, requiring no special priming to apply floor tile adhesive and low cost.

The tile council recommends that marine plywood (or equivalent) screwed down at 300mm centres is the only recognised method of stiffening a wood sub-floor in preparation of applying a flexible tile adhesive followed by the tile floor.

No insulation board or tile backer board will be strong enough to provide the tensile strength to stiffen a wood floor.

Reflective surfaces will give a greater performance when an air barrier is present (like behind a radiator). If buried within a cement layer then the reflective surface will now act as a conductor and transfer heat or cold. No useful gain can be attributed to a reflective surface when applied in this way.

If choosing tile backer boards as insulation these types of boards can be expensive. These construction boards are manufactured with a reinforcing cementitious face to give them extra rigidity and are perfectly suited as waterproof walls to tile on in wet areas. For floor insulation, this extra cement polymer coating is entirely unnecessary, reducing the insulation property of the board without adding any extra strength to the board; the board’s strength is in its polystyrene cell structure.