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All concrete slabs and screeds must be dried to 2% moisture content. This will take approximately 1 month for every 25mm thickness of slab. Concrete sub floors must be clean, dry and flat and a self-levelling compound should be used to correct any unevenness, again ensuring that it is completely dry. Readings must be taken and recorded with a Protimeter Moisture Measuring instrument or similar.

·	All existing flooring and sub floors must be in good structural condition, level and free from rot and fungus. New timber joists, battens and supporting timber should be kiln dried to 15% and under.

·	Ambient conditions should be 15°c to 27° and relative humidity in the room should be maintained at 40 - 60%

·	Wood flooring must be stickered out to acclimatise in the room where it is to be laid, in normal living conditions, for at least 2 weeks prior to installation.

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Solid hardwood floors should be glued, using an MS Polymer flexible adhesive such as Rewmar, and then nailed onto an 18mm Plywood or flooring grade Chipboard sub-floor. We also recommend that engineered timber flooring is laid in exactly the same way. The additional floor height will not effect the performance.

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Hardwood floor boards expand and contract across the grain (board width) in line with changes in moisture. The cells in the hardwood absorb moisture when the relative humidity is high, or when exposed to water, and expansion takes place. Conversely, when air moisture levels decrease, moisture content evaporates and the hardwood contracts. Expansion gaps of 15mm should be left around the perimeter of the floor. These can be covered by skirting. For spans over 6m, 2mm washer gaps must be left at 1m intervals across the entire floor.

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Floors fully bonded to the sub-floor will conduct heat better than floors floated over an underlay and will require a lower running temperature. Flooring thermostats must be installed and the heating system regulated to ensure a maximum effect of 60W/m2 and a maximum running temperature at the sub-floor surface of 27°c

·	Heating systems must be commissioned prior to the floor being installed by slowly turning the heating up by one degree per day until it runs on the highest setting and then down over a 7 day period turning the system off.

·	Pre-seals must NOT be used on screeds over under floor heating.

·	Hot water UFH systems create a smoother flow of heat than electric systems that are prone to hot Spots.

·	Do not lay rugs or carpets of any description on top of timber over under floor heating as these create hotspots.