Air Tightness Testing

Air permeability and pressure testing is now mandatory in order to minimise thermal bridging and air leakage. An Air Tightness Test will measure the airporosity of a dwelling, demonstrating any leaks in the building fabric.

1. Underfloor ventilator grilles
2. Gaps in and around suspended timber floors
3. Leaky windows or doors
4. Pathways through floor/ceiling voids into cavity walls and then to the outside
5. Gaps around windows
6. Gaps at the ceiling-to-wall joints at the eaves
7. Open chimneys
8. Gaps around loft hatches
9. Service penetrations through ceilings
10. Vents penetrating the ceiling/roof
11. Bathroom wall vents or extract fans
12. Gaps around bathroom waste pipes
13. Kitchen wall vents or extractor fans
14. Gaps around kitchen waste pipes
15. Gaps around floor-to-wall joints (particularly with timber frame)
16. Gaps in and around electrical fittings in hollow walls

Air leakage is measured in m³/h/m² at a reference pressure of 50 Pa between the inside and outside of the dwelling. Approved Document L1A of the Building Regulations defines a reasonable limit for the design air permeability is 10m³/h/m². The Energy Saving Trust adds that a good practice standard is 7m³/h/m² and best practice standard 3m³/h/m².

How many dwellings should be tested?

It is possible to reduce the number of dwellings to be tested by following Accredited Construction Details (ACDs), an updated version of Robust Details.

In a development following ACDs one test must be carried out for each dwelling type.

In a development NOT following ACDs, the guidelines below should be followed as stipulated in Approved Document L1A of the Building Regulations.

The benefits of an SIG Sustainable Solutions Air Tightness Test:

• Speedy service - typically only 7 days notification required
• Full BINDT (British Institute for Non Destructive Testing) certificate forwarded to you within 7 days of test date
• Full report sent the same day as the test
• Typical test takes only 2 hours
• Nationwide Complete Service Company to the Building and Construction Industry
• National Branch network
• National, highly skilled, trained and motivated staff
• Range of calibrated air tightness fans to suit all domestic building types
• Cost effective
• Avoid costs of site delays
• Technicians BINDT registered
• Test compliant with PART L1A Building Regulations
• ISO 9001 (2000) accredited company

Read the complete technical guide on air tightness testing (pdf kb), written by the Air Tightness Testing and Measurement Association (ATTMA)

View the Building Regulations Part L1A (pdf 318kb)

SIG Sustainable Solutions team of assessors can carry out an Air Tightness Test on up to 4 of your properties on one site for £325 (+ VAT).
Extra properties on the same site or the surveying of new sites will incur an additional charge of £325 (+ VAT)

To arrange for a quote or to order an Air Tightness Test on your property please
complete the form below or call us on 0845 873 8612.