Skip to content
  • Phone for an air tightness test01634 799115
  • Email Tophouse Assessments07990 556701
  • Send us a message
Air tightness testing

SAP Calculations To Meet Building Regulations Part L1A and L1B Compliance

New building siteWe are specialists in the assessment of new and existing buildings for Building Regulations parts L1A and L1B.

Building regulations are changing all the time and every year, get stricter and stricter when it comes to air leakages and fabric energy efficiency targets.

In fact, building regulations across the UK are now set so low that new and innovative designs and technologies are required to ensure that dwellings pass. So it's even more imperative that your building is assessed and tested by experienced professionals to ensure that it passes current building regulations. 

At Tophouse Assessments, we are fully qualified and extensively experienced enough to accurately assess your building design to the latest building regulations Part L and work with architects from the very beginning of each project to ensure they comply.


We work across Kent, London and the Home Counties, so call our experienced and qualified team today on 01634 799115 for free building regulations Part L advice and a no obligation quotation.

What is Building Regulations Part L?

Part L of the Building Regulations deals with the conservation of fuel and power. There are four approved documents to help you with building regulation compliance;

Part L1a

Part L1a for new dwellings (flats and houses)

Part L1b

Part L1b applies to work on existing dwellings or buildings converted to dwellings

L2a for commercial buildings

L2a applies to new commercial buildings

L2b for existing buildings

L2b applies to existing commercial buildings

A Full Compliance Checklist

No later than the day before the work is due to commence, you should be providing the local authority with a notice that specifies;

  • The target emission rate and fabric energy efficiency for the building
  • The calculated CO2 emission rate and fabric energy efficiency from the building as designed
  • A list of specifications to which the dwelling is to be constructed
  • An evaluation of alternative high energy efficiency systems

Whatever building regulations you're trying to pass, let Tophouse Assessments provide you with the advice and SAP calculations you need to ensure success. 

Based in Chatham, we work throughout Kent, London and the Home Counties, providing building companies and architects with the most reliable, accurate and specialist SAP calculations and air tightness testing services to help them meet all relevant building regulations.

We have recently undertaken air tightness testing projects for clients in Gillingham, Rochester, Westerham, Ramsgate, Dartford, Canterbury, Chelmsford, Larkfield, Dover, Deal, Folkestone, Aylesford, Maidstone, Colchester, Ashford, Reigate, Bexleyheath, Tunbridge Wells, Sittingbourne, Tonbridge, Guildford, London, Sevenoaks, Bromley, Orpington, Rainham, Chatham, Strood, Brighton, Croydon, West Kingsdown, Epsom and Cambridge.

Contact us today to discuss your building regulations requirements with one of our experienced and friendly team and receive free advice and guidance.