What is a PCT?

If the initials PCT spell confusion to you, we can answer the most common questions about this important regulation.

What is a PCT?

A Pre-completion Test (PCT) is a requirement under Part E of the government’s Building Regulations.  Also known as a sound insulation test, the aim is to ensure reasonable standards of sound insulation in residential buildings.  Tests are carried out on separating walls or floors to prove that they meet the regulations.

Why is a PCT necessary?

To demonstrate compliance with Part E of the Building Regulations.

What happens when a building is tested?

We send a testing engineer to visit the property who will need to have access to both sides of a wall or floor (known as a separating element).  For airborne noise such as speech or the radio, we create a very loud noise on one side and measure how much sound is lost on the other.  For impact noise (such as from people walking around) we have a standardised noise source called a tapping machine.  Both floors and walls are tested for airborne sound insulation.  For impact sound insulation, only the floors are tested.

Can I do the test myself?

No.  All testers must be registered with an organisation such as the Association of Noise Consultants (ANC) or the United Kingdom Accreditation Service (UKAS).

Can I opt out or is there an alternative?

You cannot opt out unless you are registered with Robust Details.  This is an alternative pre-approved construction scheme.  Some builders choose this option rather than a PCT, but the requirements are often much stricter as the construction must be built exactly to the guidelines. Whilst doing away with the need for a PCT, Robust Details limits the construction options and only applies to new builds.    Once a building is inspected any significant deviations can lead to de-registration from the Robust Details scheme and a PCT being required.

Adrian James Acoustics can advise as to the suitability of a PCT.  Call us on 01603 721511 if you are unsure.

Norsonic tapping machine

What instruments or machines are used?

The test kit normally comprises a loudspeaker, a microphone, a pre-amp and a computer or sound level meter.  For impact tests a tapping machine is required. This apparatus drops small weighted hammers on to the floor to excite the floor structure. All equipment is rigorously maintained, with a certificate proving it has been calibrated to strict tolerances.

How long does a PCT take?

This depends on the complexity of the job.  A single airborne test across one wall may take 15 to 30 minutes.  A large development may have to be tested over several days.

I have multiple houses or flats in the same area, so do they all have to be tested?

No.  Pre-completion tests are carried out by sampling one in ten plots on a development, for each type of construction built.

For 30 flats, three sets of tests would be required, assuming the constructions are all the same.  A set comprises of:

  • 2 airborne tests across walls
  • 2 airborne tests across floors
  • 2 impact tests across floors

What is the pass rate?

Pass rate data is not readily available.  However, if the separating construction and all flanking elements are designed and built correctly, the tests should pass.

What happens if a test fails?

The results should be submitted to Building Control as they will confirm what happens after a failed test.  It is typical for remedial work to be required to improve the sound insulation in the problem areas.  Additional testing will be needed to demonstrate compliance. On large developments, Building Control may request additional measurements are taken to demonstrate that the necessary work has been carried out to the whole site, rather than a few plots.

Why chose Adrian James Acoustics to carry out a PCT?

We have years of experience in carrying out hundreds of PCTs, along with inspections for Robust Details. All of our testers are also consultants, so in the event of a test failing we can advise on how to fix a design or construction issue.

How much does it cost?

This varies depending on factors such as the location of the tests.  We typically charge £350-400 for one or two wall tests.

Please call us on 01603 721511 and we can provide individual quotations upon request.

For more information, watch our Principal Acoustics and Theatre Consultant Ian Rees in his popular video presentation: