Changes to Part L and how it will effect you (New Build).

This month the interim Part L document will be published which is part of the Government's long term plan to reach zero carbon homes. The regulations will officially change in June 2022, the initial issue is to forewarn the construction industry and allow us to prepare for the change.

Significant changes are coming which will affect all new homes constructed after June 2022 meaning many forms of ‘traditional’ building will no longer be viable. Roughly there will be a 30% increase of all fabric standards in this change. 

The key change that will affect all homes is the adjustment to thermal bridging values within SAP calculations. Thermal bridges are the junctions between different building elements such as floor and wall or wall and roof. Previously Government issued accredited details could be used to cover these junctions which included a standard psi value (thermal bridging value) for each junction. As of June 2022 these details will be obsolete and a default value for these will be set at 0.2. This effectively renders these details as unusable.

To overcome this change there are two options, either each junction for the building is calculated individually which is a costly exercise or standard junction details are used from manufactures which have had their psi values calculated. The later option has the added difficulty that once specified the insulation can not be changed without recalculation of the SAP assessment. This presents a problem for many builder who have benefited from the ability to change insulations based on availability and price. 

It is important for builders big and small as well as Clients who employ them that the flexibility on specified products will be much reduced with this change.