FAQs
How much insulation do I need?
Insulation within the ground floor of properties is required to comply with Part L of the building regulations regardless of whether UFH is being installed. A ground floor of a domestic property is to be insulated so that it has a U value of 0.25 or less (note the lower the U value the greater the resistance to heat transfer, the reciprocal to an R value). When calculating a U value the floor area and the exposed perimeter of the building need consideration as the building will lose more heat around the perimeter than in the centre. Generally 70mm of a PIR or PUR board (such as Kingspan or Celotex) will satisfy for ground floors however your architect should confirm the exact requirements with you.
On intermediate floors there is no requirement under building regulations to have thermal insulation. However, BS EN 1264 (the British and European Standard which applies to water based underfloor heating systems) requires that intermediate floors that have a heated area below are to be insulated and the insulation is to have a thermal resistance of 0.75m2K/W or greater (note the thermal resistance (R Value) is the ability of a material to resist heat flow). The greater the r value the more efficient the insulating material will be 25mm of a PIR or PUR will suffice.
Please note in flats where there is a separate dwelling below acoustic insulation will be required to comply with Part E of the building regulations.
What size boiler do I need for Underfloor heating?
The size of boiler required will vary with each system. The boiler will need to be sized in order to generate enough heat to satisfy the heating requirements and in most cases provide enough heat to supply warm water to a property. Care should be taken to ensure that the boiler is not over sized as a correctly sized boiler will work far more efficiently than an over sized one
Where should I position the room thermostats?
Each room stat needs to be located in the room it is controlling; we recommend that they be positioned in a draft free place, out of direct sunlight and not near to any other heat sources such as cookers or towel rails.
A thermostat should ideally be positioned in way that it can take a fair reading of the environment that it is situated and it should be positioned away from any heat gains or heat losses which may offset the reading. In practical terms this means that it should be positioned in a draft free place and away from heat sources such as direct sunlight, fire places, cookers etc
What type and depth of screed do I need?
In domestic properties we recommend a 65mm 4:1 sand/cement wet screed mix. If used in a commercial property this should be increased to 75mm. The screed should be laid for a minimum of 28 days prior to switching on the system. If is possible to get specialist screed supplements which will reduce the drying time and/or reinforce the screed. Please contact the specialist manufacture for further details on drying times and/or depths with regards to anhydrite screeds or screed supplements as the guidance does differ depending on the manufacturer.
Where should I locate the Underfloor Heating manifold?
The UFH manifold is effectively the distribution point for the UFH coils. The range of Pro Underloor Heating packs can heat an area of up to 100m2. Ideally a manifold will be centrally located which will reduce the amount of distribution pipe work to each heated area or zone.
Are water based Underfloor Heating Systems better than Electric ones?
Providing that a building is well insulated then both systems will be suitable. The size of area, type of floor construction etc will influence the capital price of each system, in addition to these factors, the fuel source should be considered. The UK is the largest producer of gas and within the EU and the domestic gas supply network allows access to approximately 75% of domestic dwellings in the UK. Although tariffs differ dependant on supplier and region, electricity is approximately 2-3 times more expensive than gas.
When is the Underfloor heating system installed?
UFH can be installed during all seasons. Prior to installation ensure that the area is clean and dry. If the building hasn’t been weather proofed ensure that electrical and mechanical products will not affected or damaged. During the winter months if the pipes have been filled with water and the building has not be weather proofed a glycol solution is to be added to prevent the water in the pipes from freezing
Are there any restriction on carpets, tiles etc?
Most types of floor covering are fine to use with underfloor heating, tiles, vinyl, and stone coverings are particularly suitable as they allow the heat to pass through easily. Wood and carpet are also suitable too, however thick carpets and underlays will affect the performance of the system. We recommend that a carpet and underlay has a combined thermal resistance not exceeding 0.15m2K/W which is equal to a tog value of 1.5. A TOG Value of 2,5 should never be exceeded.
Consideration should be given to both the carpet and underlay. Whilst it is important to ensure that both items are to the occupants requirements it is also important to ensure that adequate heat can pass through. Felt underlays are generally poor conductors of heat and are not recommended where as thin rubber underlays usually perform the best. Tredaire Technics 5 (tog value = 0.5) offers good thermal performance without compromising comfort. Choosing an underlay with a low tog value will allow for greater flexibility over the carpet used.
