Energy Efficiency

The low U-values that can be achieved by using the Kingspan TEK Building System e.g. 0.22 W/m²·K in a wall and 0.18 W/m².K in a roof with no additional insulation, mean that not only can the System meet and exceed current Building Regulations / Standards but it also can meet the U-values that are expected to be set in future changes to the Building Regulations / Standards in 2012 and beyond. Extremely low U-values e.g. 0.10 W/m²·K, can also easily be achieved with the Kingspan TEK Building System by applying additional insulation e.g. Kingspan Kooltherm K18 Insulated Plasterboard. This means low running costs and impressive comfort for the lifetime of the building.

In addition to the Kingspan TEK Building System panel’s excellent thermal performance, the closed cell structure of its rigid urethane insulation core does not allow movement of air within the wall. The insulation will not sag or physically deteriorate over time as may be the case with other insulating materials.

The proprietary jointing system used with the Kingspan TEK Building System can create a very air-tight structure (air permeabilities as low as 1 m³/hour/m² at 50 Pa) with little opportunity for air leakage.

U-value calculations for a conventional timber framed house always have to take into account the effects of cold bridging. Cold bridging occurs where a material with a significantly worse thermal conductivity interrupts the normal continuous layer of insulation.

The 15% figure includes:

• 38 mm timbers at 600 mm centres for 1 and 2 storey buildings; and
• all timbers such as noggins (also known as repeated cold bridges).

The 15% figure does not include:

• timbers that are outside the wall area used for heat loss calculations;
• timbers (max. depth 50 mm) around window zones and lintels (max. depth 175 mm); and
• intermediate floor joists that are not insulated behind.

The SIP technology, upon which the Kingspan TEK Building System is based, means the insulation layer is not interrupted by repeating studwork. Therefore there is less cold bridging which can yield a better thermal performance. There are however some cold bridges e.g. where timbers are used to support point loads etc. However, as with U-value calculations for timber frame the same rules apply for timbers that do not have to be included.

Due to the continuity of insulation within its panels, the Kingspan TEK Building System provides greatly enhanced thermal reliability when compared with other more traditional forms of construction.

Example 142 mm thick panel.

Thermal bridges exist at:

• 140 mm x 38 mm soleplates where they have been installed on top of the floor screed;
• 50 mm x 110 mm timber headplates;
• half the 50 mm x 110 mm end timbers which are fixed into the wall panels to enable them to be butt jointed at corners;
• half the 50 mm x 110 mm end timbers which are fixed into the roof panels to enable them to be butt jointed over the ridge beam; and
• the 110 mm x 100 mm timbers posts which are occasionally used at the junctions between panels for structural reasons.

This results in a system that only has 4% thermal bridging from timber elements for a typical domestic building wall (up to 15% or more with a traditional timber frame wall) and 1% thermal bridging from timber elements for a typical domestic building roof (6% in a typical domestic roof with insulation between joists or rafters). Guidance on thermal bridging in the Kingspan TEK Building System should be sought from Kingspan TEK Technical Services Department.

The Kingspan TEK Building System does not suffer from:

• sagging insulation;
• wet insulation due to exposure on site which could reduce thermal performance;
• gaps and voids in insulation coverage left by poor site workmanship; or
• compressed loft insulation from storage of items in the loft.

The Kingspan TEK Building System is ideal for the construction of an air-tight building envelope. The System’s proprietary jointing system provides an effective air seal.

The Kingspan TEK Building System does not suffer from the problems associated with other common construction techniques:

• air leakage through poorly sealed sockets, switches etc. in timber frame walls;
• air leakage at floor zones through wet plastered masonry cavity walls;
• air leakage under skirting boards and through poorly sealed sockets, switches etc. in dry lined masonry cavity walls; and
• air leakage through poorly sealed loft hatches and top storey ceiling light fittings.

The Kingspan TEK Building System achieves excellent results in blower door tests e.g. 0.08 air changes per hour at normal air pressures or 0.91 air changes per hour at 50 Pa (approximately 1 m³/hr/m² at 50 Pa).

NB: To put this in context, a recommendation for air-tightness in current 2006/2007 Part L Regulations and Standards in the UK is 10m³/hr/m² at 50 Pa for dwelling.
This is currently given as a good guideline for the purpose of calculating SAP.

The Kingspan TEK Building System is again clearly bringing future building standards home today.