What do I need to get tested?
Where approved construction details have been adopted, one test should be carried out on each dwelling type on each development. Separate blocks of flats are treated as separate developments. Each of the following constitutes a change of dwelling type:

• Change in method of construction e.g. timber frame and brick and block
• Ground floor, mid floor & top floor flats
• End of terrace & mid terrace
• Semi-detached & detached
• Significant changes in building floor area

Where approved construction details have NOT been adopted, then each dwelling type is to be tested as above but with an increased sampling regime as can be seen below:

Number of instances of the dwelling type	Number of tests to be carried out on the dwelling type
4 or less	One test of each dwelling type
Greater than 4, but equal or less than 40	Two tests of each dwelling type
More than 40	At least 5% of the dwelling type*

(* If the first 5 dwellings tested all pass, then the sampling frequency can be subsequent reduced from 5% to 2%)

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For developments where no more than two dwellings are to be built, one unit must be tested (or two if they are different dwelling types).
The only exceptions are if:

• A dwelling of the same dwelling type has been built by the same builder within the last 12 months and successfully passed the air tightness test
• A default poor value of 15m3/h/m2 has been used in the SAP 2005 calculations.

The effect of using this cautious value would then have to be compensated for by improved standards elsewhere in the dwelling design

Who selects what dwellings will be tested?
The Building Control Officer will choose which units are to be tested in accordance with the sampling regime explained above.

What happens if a dwelling fails a test?
In the unfortunate event that the initial test result is unsatisfactory then Home Integrity Testing is there to help make sure that you pass on the second attempt. Three actions are required:

1. Remedial work will need to be undertaken on that unit.
2. A retest will need to be booked to test the same unit (after remedial work has finished).
3. Also an additional test on the same dwelling type will be required.