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Over 19 years experience providing property surveys for all building
types.
Expertise covering a wide range of surveying needs for your
building.
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A building with a high amount of air leakages is in danger of a vast increase in the rate at which heat is lost from the property; on the other hand if there isn’t enough ventilation the air becomes stagnant, increasing the chances of mould and damp, which can be potentially dangerous to occupants.
Approved document F defines airtightness as a descriptive term for how resistant a building’s envelope is to air escaping or entering the property, whilst all other ventilation is closed (ie windows, doors, vent systems).
Under the current Approved Document L (2021 edition) every new home in England should be tested, not just a sample of each house type, and new non-domestic buildings must be tested too unless they are under 500m² and the energy calculation uses the default figure of 15 m³/(h·m²). For conversions a test isn't compulsory, but it may help achieve a pass on the SAP Compliance Report.
Simply request your quote using our contact form or by phone. Our customer care team will quickly get in touch during opening hours.
We will arrange an appointment with you, carry out the survey, and once completed send you an invoice.
As soon as we receive payment of the invoice, we will email your Air Permeability Test Results. We also offer corporate accounts, with survey delivery on completion and monthly billing.
An air tightness test measures how much air leaks out of a building through gaps in its walls, floors, roof and around its windows and doors. It's also called an air permeability test, an air test or a blower door test.
We close the windows, doors and trickle vents, seal the extract fans, then fit a large fan into an outside doorway and use it to pressurise or depressurise the building. The result is the volume of air leaking each hour through each square metre of the building's outer surface at a pressure difference of 50 pascals, written as m³/(h·m²) at 50 Pa.
Yes, if you're building a new home in England. Approved Document L (the part of the Building Regulations that covers energy efficiency, known as Part L) says every new dwelling should have an air pressure test. Testing a sample of each house type on a development is no longer enough.
New commercial and other non-domestic buildings need a test too. The exception is a building under 500 m² of floor area, where the developer can skip the test only if the energy calculation uses a deliberately poor figure of 15 m³/(h·m²).
Conversions and extensions don't carry the same automatic duty, but a tested figure can help a SAP calculation pass, so your SAP assessor may recommend one.
A good result is one at or below the design figure used in your SAP or SBEM energy calculation. Lower numbers mean a tighter building. A new home must also come in no worse than 8 m³/(h·m²) at 50 Pa, the limit set in Part L, and the same limit applies to new non-domestic buildings.
If the result is worse than the design figure, the energy calculation is re-run with the measured figure and has to pass again. So the number to aim for is the one your assessor designed to, not just the legal limit.
Tighter isn't always better on paper. In a naturally ventilated home, SAP gives no extra credit for a result below 3 m³/(h·m²). It only counts below that where the home has continuous mechanical ventilation.
Our air tightness tests start from £199.95+VAT. The price depends on how many homes or units we test, their size and where the site is. Testing several plots on the same visit can bring the price per plot down.
Our prices are competitive and every site is quoted on its own merits. Send us the plans and we'll come back with a firm figure, and the advice that goes with it.
For residential properties, if the air test fails, our assessor will inform the site contact and discuss the result, potential problems that could be causing the failure and what could be done to correct these (for example, this could be as simple as fitting draft excluders to a loft hatch).
For commercial properties, if the building fails we can offer diagnostic testing services such as smoke tests and thermographic surveys to identify why the property has failed.
New homes must test at 8 m³/(h·m²) or better at a pressure of 50 pascals. The SAP calculation for building control is then re-run with the tested figure and must still pass, so aim for the design figure your assessor used.
New commercial buildings have the same limit of 8 m³/(h·m²) at 50 pascals, and their as-built SBEM calculation (the commercial equivalent of SAP) uses the tested figure in the same way.
Following the method for testing required by building regulations as set out in ATTMA TSL1 (residential) and ATTMA TSL2 (commercial), all doors, windows and vents are closed or sealed, any flames in fireplaces will also have to be put out.
Next, a piece of equipment that comprises of a door holding a large fan is mounted inside the frame of an external door (generally the front door is used, providing it is “standard" size), when the fan is turned on it depressurises the building by extracting air from the property.
The air permeability of the property is calculated using the difference between the internal and external pressure of the building envelope.
Part E of the building regulations require that your new build or conversion property conforms to its Sound Insulation Testing limitations.
Building control may also require you to carry out Water Use Calculations to confirm that your property is compliant with that max water usage per person per day, as set out in part G.
In accordance with Approved Document O, your property will also require a Simplified Overheating Assessment, and potentially TM59 Overheating Calculations.
The basic information we need to be able to provide you with a price for the survey is:
Once we have provided you with a quote, if you wish to go ahead and book we will also need invoicing details and contact details for whoever will be meeting us on site. We don't charge up-front, but will invoice you for the work on completion, and release the air permeability certificate to you upon receipt of payment. Our quote includes use of equipment and travel.
After you have booked with us we will contact you or if you prefer an alternative site contact to arrange an appointment. Once we have visited site the report should be ready the next working day, at which point we will contact you to let you know it's ready and provide you with an invoice. On payment of the invoice we will email your Air Permeability Pass Certificate.
Use our online booking tool to quickly get a quote for your Air Tightness Test.
Our prices start from £199.95 + VAT, depending on size and location of the property.
Air tightness testing, or air permeability testing, determines “leaks” in a building's fabric and to what extent air escapes through the leaks (not including vents, windows, doors, etc. which are sealed during testing).
Air tightness testing is done to show compliance with Building Regulations.
Every new home in England should be tested under Part L. New non-domestic buildings must be tested too, unless they are under 500m² and the energy calculation uses the default figure of 15 m³/(h·m²).
A standard air tightness test appointment takes between 45 minutes to an hour.
New homes and new commercial buildings must test at 8 m³/(h·m²) or better at 50 pascals. If the design figure in your SAP or SBEM calculation is tighter than that, it's the one to aim for.
Yes, there are several requirements. We will send you a detailed checklist before your appointment.
Our prices start from £199.95 + VAT, depending on size and location of the property.
19+ Years Industry Experience
Dedicated customer & tech support
Easy 3 step booking process
Every property certificate, swiftly delivered
