Thermal Kit Specification | U-Value

Our 1 star option is the basic specification that is required to comply with national building regulations. Where open panel options are concerned, we would like to highlight that you should allow for additional site labour costs for the fitting of insulation/service void materials.

	*5 Closed**	*4 Closed**	*3 Closed**	*3 Open**	*2 Closed**	*2 Open**	*1 Open**

Ground Floor – by others
Insulated Concrete Ground Floor Designed / Supplied by others
See Assumed Insulation Thickness	180mm PU	150mm PU	120mm PU	120mm PU	100mm PU	100mm PU	90mm PU
U Value W/m²K (‘below slab)	0.10	0.12	0.15	0.15	0.17	0.17	0.18


External Walls
Breather Membrane	Reflective	Reflective	Reflective	Reflective	Reflective	Reflective	Reflective
OBS Sheathing	9mm	9mm	9mm	9mm	9mm	9mm	9mm
Framing	235mm	184mm	140mm	140mm	90mm	140mm	140mm
Insulation	235mm PU	184mm PU	140mm PU	140mm Frametherm 32	90mm PU	140mm Frametherm 40	140mm Frametherm 35
OSB Sheathing	9mm	9mm	9mm	Not applicable	9mm	Not applicable	Not applicable
Vapour Control Layer	Reflective	Reflective	Reflective	Polythene	Reflective	Reflective	Not applicable
PU Layer	–	–	–	25mm	–	–	–
Service Void / Battens	35mm	35mm	35mm	35mm	35mm	35mm	Not applicable
Plasterboard	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Vapoursheld
U’ Value W/m²K	0.11	0.13	0.15	0.15	0.21	0.20	0.22

Roof -Horizontal Ceiling
Insulation	560mm Frametherm 35	560mm Frametherm 40	420mm Frametherm 40	420mm Frametherm 40	370mm Frametherm 40	370mm Frametherm 40	280mm Frametherm 40
U’ Value W/m²K	0.07	0.08	0.10	0.10	0.13	0.13	0.15

Roof -Coomb/Sloping
Insulation	200mm PU	170mm PU	170mm PU	170mm PU	140mm PU	140mm PU	140mm PU
Vapour Control Layer	Polythene	Polythene	Polythene	Polythene	Polythene	Polythene	Polythene
PU Layer	25	25	25	25	25	25	25
Service Void / Battens	35	35	35	35	35	35	35
Plasterboard	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain
U’ Value W/m²K	0.12	0.13	0.13	0.13	0.15	0.15	0.15

Roof – Hanging post
Insulation	140mm PU	120mm PU	140mm Frametherm 35	140mm Frametherm 35	140mm Frametherm 32	140mm Frametherm 32	140mm Frametherm 40
Vapour control layer	Polythene	Polythene	Polythene	Polythene	Reflective	Reflective	Reflective
PU Layer	25	25	25	25	–	–	–
Service Void / Battens	35	35	35	35	35	35	35
Plasterboard	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain	15mm TE Plain
U’ Value W/m²K	0.14	0.15	0.17	0.17	0.20	0.20	0.22

External Joinery – W/m²K
Windows (whole product)	0.90	1.10	1.20	1.20	1.30	1.30	1.30
Roof Lights	1.15	1.30	1.30	1.30	1.50	1.50	1.60
External Doorsets (average product)	1.20	1.20	1.20	1.20	1.40	1.40	1.60

Each element of the building envelope – wall, roof, floor,windows and external doors has a role to play in minimising heat loss. The insulating effect of each of these elements is measured by its U value – the lower the U value, the better its thermal performance.

Valutherm+ wall, floor and roof panels will last for the life of the building – unlike renewables that need to be controlled, require frequent maintenance and, often, wholesale replacement during the lifetime of a property. In contrast, the Valutherm+ system is a Fit and Forget, Fabric First solution.

Building towards greater energy conservation

All new buildings must now reach increasingly higher standards of energy conservation. The Scottish Building Standards and the Approved Documents Part L of the English Building Regulations are driving the reduction of carbon emissions in new buildings. Building in timber frame makes it easy to achieve a high performance building fabric that maximises thermal performance and minimises unwanted air leakage commonly known as draughts.

It should be noted that both the Scottish Building Standards and the Approved Documents Part L of the English Building Regulations are the minimum required to comply, with the regulations being amended on average every three years imposing ever more stringent requirements of energy conservation it makes sense to consider ‘future proofing’ your home by building to a better thermal standard now.

Scottish Building Regulations – Section 6

For nearly fifty years, Scotland has had its own set of Building Regulations. For many years the energy standards in the regulations were set at a modest level, broadly following those that existed in the remainder of the UK. As we moved into the 21st century and the climate change agenda gathered momentum, the energy standards now incorporate the best levels of thermal insulation in the UK, reflecting Scotland’s colder climate.

The standards introduced at the start of October 2015 reduce the CO² emissions from new buildings by a further 21.4% from the 2010 Regulations. These standards are comparable with the best in Europe. All things being equal, the new Scottish Building Regulations will reduce CO² emissions from new buildings by around 45% when compared to the 2007 standards.

English Building Regulations – Part L

There is also a greater emphasis on ensuring that the building construction meets the standards assumed at the design stage and that the heating and hot water systems are correctly commissioned.

The energy efficiency standards in Approved Document Part L were further strengthened in the 2010 amendments, requiring a 25% decrease in target CO² emissions and lower levels of un-wanted airleakage, the high thermal performance provided by using timber frame in the building fabric makes the new targets easily achievable.

Thermal performance

Timber frame has the advantage over masonry construction as the insulation is incorporated within the timber frame panels as opposed to being fitted in the area that was traditionally the cavity in masonry construction, this results in the timber frame construction achieving a higher level of thermal performance in a ‘thinner’ wall thereby negating the need for increased foundation and under building costs as is the case with masonry construction.