Northern Air Tightness Testing Services Ltd is fully accredited with BINDT and ATTMA we specialise in carrying out Air Pressure Testing of dwellings and small commercial buildings.

Only certification issued by a formally accredited company like NATTS will be accepted by the necessary approval bodies.

We are an independent company and have been operating since 2009. We are experienced in carrying out air pressure tests for large national house builders and independent self builds alike. We pride ourselves on providing an efficient, reliable and uncomplicated service which is tailored to your requirements.

Our aim is to offer a package to our clients ensuring that they meet the requirements of Part L1A of Building Regulations.

Our service would include a check list at the early stages of a build and the provision of practical advice and support throughout. A pre test site visit can be arranged at an appropriate stage which will contribute to achieving favourable results.

Certification can be forwarded on the day of a successful test with a view to assisting in meeting Client demands and deadlines.

We operate with a 100 mile radius of Harrogate, however would be willing to discuss individual needs.

What it is Air Pressure / Air Leakage Testing
Since 2006 all new domestic and commercial buildings have been required to be tested for Air Permeability, in order to comply with Part L1 and Part L2 of the Building Regulations.

This means that for a dwelling to be deemed as habitable and meet Part L1A of the Building Regulations it needs to achieve the standard of air tightness set and be energy efficient. (The target Air Test value is set within the Design Stage SAP) In subsequent amendments to Building Regulations the levels of air tightness have become more stringent as dwelling emission rates have been lowered. This has put a greater emphasis on building more air tight houses.

Air Tightness Testing is a method of calculating this by quantifying how much air leaks in or out of the building.
For this we use the term 'Air Leakage' which is defined as ‘the uncontrolled flow of air through gaps and cracks in the building fabric’

Areas for potential leakage which should be given particular attention during the build process are:

Behind Kitchen/Utility units or fitted bedroom or bathroom furniture.
Where all walls meet a floor.
Around windows and external doors.
Around any pipework leading into or out of the building.
Around sockets and other electrical points.
Testing Regime
October 2010, L1A Building Regulations required that Air Pressure Testing is carried out on 50% of a particular ‘dwelling type’ or a minimum of three units of each ‘dwelling type’, whichever is the least number.

There are a number of different ‘Dwelling Types’

Detached Houses
Semi-Detached House
End Terrace House
Mid Terrace House
Top Floor Flat
Mid Floor Flat
Ground Floor Flat
In addition to be classed as the same ‘dwelling type’

they must employ the same construction methods
the difference in floor area must be less than 15%
they must have a difference of no more than one significant opening