Requirement L1, Regulation F and building new properties


The government have introduced new guidelines and regulations for people building new properties.


There are pages and pages of rules and regulations, 104 pages just on Requirement L1 and many hundreds more explaining what is meant in the 104 pages!


What is Requirement L1 about?


The short explanation is to make homes more efficient in terms of heat loss and heat gain. To achieve this the architect now has to analyse and determine the efficiency of the dwelling.


Using complicated assessments of the “U” values, which relate to the energy efficiency of all components in the dwelling, the new property has to achieve the stringent new requirements.


In Requirement L section one there are specific guides created for:

1. Calculating the target primary energy rate, target emission rate and target fabric energy efficiency rate

2. Calculating the dwelling primary energy rate, dwelling emission rate and dwelling fabric energy efficiency rate


Packing a home full of insulation and the most energy efficient windows and doors just part of what is needed.


A super insulated home, completely draft free is bad for your health – which is where regulation F comes into play.


The problem with a “sealed” home is that moisture from breathing, washing, cooking and natural body cooling has no where to go. The moisture levels increase which results in condensation, where there is condensation there is damp and then mould.


Regulation F challenges the architects to develop homes with minimum levels of airflow so that the air in the dwelling is refreshed at a specific rate. For some properties this means a mechanical system will need to be installed. A system that uses fans and ducting to move air through a house.


The good news for home owners is that all the architects have been mulling over the new regulations for some time and as builders we follow the plans to ensure you have a property that complies with these new rules.