New Welsh Part L 2014 – Retrofit, Material Changes of Use and Extensions

Welsh building regulations

The third of three blogs on the new Welsh Part L 2014 Building Regulations. This one is about retrofit, material changes of use and extensions.

The Welsh Part L 2013/14 Approved Documents should be implemented from 31st July 2014. At a recent event an overview of the Welsh versions of Approved Documents L1B and L2B was produced. A summary of their contents is detailed below:

Conservatories:

The exemption for conservatories of floor area less than 30m² and with thermal separation between the conservatory and the dwelling remains in place, however any fixed heating system, whether separate or part of the main system, will now mean that the exemption from regulations compliance is lost and the conservatory would be classed as an extension.

Domestic Refurb & Extensions

It was noted during the presentation, that anecdotally, refurbishment and retrofit is an area of poor notification and compliance with requirements, so the emphasis was more around making sure that this improves, before considering any improvements in targets.

Where elements are to be renovated or upgraded, the standards remain unchanged from L1B 2010 (reproduced below). The slight caveat being that the threshold is to be removed.

Fabric standard

2010 Threshold (W/m²K) – Now removed

Improved U-value (W/m²K)

Wall – cavity insulation (W/m²K)

0.70

0.55

Wall – external or internal  insulation (W/m²K)

0.70

0.30

Floors (W/m²K)

0.70

0.25

Pitched Roof – Insulation at ceiling level (W/m²K)

0.35

0.16

Pitched Roof – Insulation between rafters (W/m²K)

0.35

0.18

Flat Roof or with integral insulation (W/m²K)

0.35

0.18

Windows & Doors (W/m²K)

1.6

1.6

For new thermal elements – e.g. extensions, the requirements have been tightened:

Fabric standard

Previous 2010 values

New 2014 requirements

Wall (W/m²K)

0.28

0.21

Roof (W/m²K)

0.16 / 0.18

0.15

Floors (W/m²K)

0.22

0.18

Windows & Doors (W/m²K)

1.6

1.6

These values align with the backstops for domestic new build.

Compliance can be shown either from following the reference values, or from an area weighted U-value trade off, or through SAP, showing an equivalent carbon target approach (greater design flexibility). The greater design flexibility approach has also been expanded to allow conversions, renovations, material changes of use and conservatories to also show compliance in a similar way using SAP.

On top of these, where a dwelling is extended (such that there is an increase in habitable space), consequential improvements will now be applied to buildings of all sizes triggered by extensions in habitable spaces (if larger than 10m²). Any dwellings not already reaching required levels will need improving so that they do by carrying out the following:

  • Fully filling cavity walls with insulation (Where appropriate).
  • Increasing loft insulation to 250mm insulation.
  • Upgrading hot water cylinder insulation.

In addition to the domestic, non domestic provisions have some proposed improvements:

Non-Domestic Refurb & Extensions

Where elements are to be renovated/upgraded, the standards remain unchanged from L2B 2010 (reproduced below). The slight caveat being that as with L1B, the threshold is to be removed.

Fabric standard

2010 Threshold (W/m²K) – Now removed

Improved U-value (W/m²K)

Wall – cavity insulation (W/m²K)

0.70

0.55

Wall – external or internal  insulation (W/m²K)

0.70

0.30

Floors (W/m²K)

0.70

0.25

Pitched Roof – Insulation at Ceiling level (W/m²K)

0.35

0.16

Pitched Roof – Insulation between rafters (W/m²K)

0.35

0.18

Flat Roof or with integral insulation (W/m²K)

0.35

0.18/0.20

For new thermal elements e.g. extensions, the requirements have been tightened (as with domestic):

Fabric standard

Buildings essentially domestic in character (e.g. halls of residence or care homes) (W/m²K)

Other non domestic buildings

(W/m²K)

Walls (W/m²K)

0.21

0.26

Floors (W/m²K)

0.18

0.22

Pitched Roof – Insulation at Ceiling level (W/m²K)

0.15

Pitched Roof – Insulation between rafters (W/m²K)

0.15

0.18

Flat Roof or with integral insulation (W/m²K)

0.15

0.18

Windows & Doors (W/m²K)

1.6

1.8

A new category has been added ‘buildings essentially domestic in character’, such as care homes, or halls of residence. For these, where extended, tighter standards are required.

As with domestic, optional approaches for showing compliance have been extended for material alterations, extensions, conversions and renovations to allow an equivalent carbon target approach to be used, rather than U-value trade off. For non-domestic, consequential improvements will now be applied to buildings of all sizes triggered by extensions, new fixed building services, or an increase in the capacity of existing services.

For non-domestic, the consequential improvement amount is set by 10% of the value of the principal works and measures can come from either EPC recommendations, or a green deal assessment, or from a table of recommendations from L2B.

Other Blogs on this topic:

New Welsh Part L 2014 – Domestic buildings
New Welsh Part L 2014 – Non-Domestic buildings

To keep up to date with all our latest blog posts you can follow the blog by clicking this RSS Feed link or by following us on Twitter @KingspanIns_UK or on Linkedin.

Share this blog post with your friends and colleagues by clicking on the social media icons below.

Print this page
About

Jon Ducker is a qualified energy assessor working for Kingspan Insulation Ltd. He has an extensive knowledge of energy efficiency, renewable energy systems and sustainability in buildings with an expert knowledge of the relevant sections of buildings regulations and standards and their interactions with SAP. He provides authoritative advice regarding energy assessments for a wide range of public and private sector clients.

0 comments on “New Welsh Part L 2014 – Retrofit, Material Changes of Use and Extensions

Leave a Reply

Your email address will not be published. Required fields are marked *