Recent thermal changes have required a significant improvement in the thermal performance of all building elements, but the improvement required in floors has been the most marked. To meet current regulations, new designs require an improved thickness of insulation.

The thermal performance of ground floors is determined by a combination of the thermal resistance of the floor construction and the insulation provided by the ground.

Rockwool Rockfloor is a rigid, non combustible tissue faced slab, offering high compressive strength. The product had been specifically designed to meet new thermal and acoustic regulations. 

Placing the Rockfloor below the concrete slab allows the concrete slab to act as a "thermal store" helping maintain steady temperatures within the building.
 
Placing the Rockfloor above the slab (below the floor finish) allows the building to respond more quickly to the heating system. 

In the case of suspended concrete floors, Rockfloor insulation is installed above the deck, either under a screed or timber boarding. Positioning Rockfloor under chipboard or a screed will allow the building to heat up quickly because the insulation is close to the inside of the building. 

In suspended timber ground floors Rockwool Flexi is normally located between the joists.

U value requirements in the Building Regulations for ground floors: (U value (W/m2K)

England, Wales  0.25 (Building Regulations Part L1 & L2 2001 edition)
 
Scotland           0.25 or 0.22 (Building Standards (Scotland)  Part J 2001 edition)
 
Rep. of Ireland  0.25 ( Part L technical guidance Document  2002 edition)

Perform your own U-value calculations and Condensation Risk Analysis with BuildDesk U the free downloadable software from BuildDesk. For U-value training courses and consultancy visit the BuildDesk website to find out more.

Determining "U" values
Unlike walls and roofs, the heat loss through a ground floor varies with its size and shape. The Building Regulations require that ground floor U-values are calculated, in accordance with BS EN ISO 13370: 1998 .

The Standard uses the ratio of the exposed floor perimeter to the floor area to take account of the variation in heat loss due to floor size and shape (P/A ratio).

The measurement of the perimeter (P) and area (A) should be to the finished inside surfaces of the perimeter walls that enclose the heated space (unheated spaces such as porches or integral garages should be excluded).

In the case of semi-detached and terraced dwellings and blocks of flats, the floor dimensions can either be taken as those of the individual dwellings themselves, or of the whole building. When considering extensions to existing buildings, the floor dimensions may be taken as those of the complete building including the extension.

To comply with building regulations and as part of the design process in the residential sector, you may need to submit SAP calculations to Building Control. If you require more information on SAP 2005 we suggest you visit the BuildDesk website. BuildDesk produces the leading SAP 2005 software tool, BuildDesk Energy Design, together with training and consultancy services. BuildDesk is a member of the Rockwool Group 
 
Find out more about technical information, U values, dimensions and installation guides by clicking on the product links.

Fire
Find out more  in Rockwool FirePro range fire prevention solutions for ground floors.

DXF   DWG   DWF

Download free DWG from Autodesk & Adobe Reader