30 Aug 2016 - Much tape doesn't mean much airtight
A new house recently tested had to be tested on 3 visits to get it to a relatively good standard of about 3.5 m3/hr.m2 - the first test being outside of the 2011 Part L requirements of at most 7 m3/hr.m2.
Three of the noticeable things about this house:
- Lots of tape - in fact at least 7 different tape types from 4 different suppliers
- Lots of membrane - 3 different types
- Fair bit of expanding foam - much of it not doing its job
 numerous types of tapes |
 Various membranes |
 Example of foam sprayed in, but not expanding as much as the worker expected - plenty of gaps left |
 Example of total loss of foam - this is looking upwards, the foam may have fallen down after application |
06 January 2016 - 2015 in Airtightness
Just for interest: the best and worst tests of the year in 2015
| Best Air Permeability test | Worst Air Permeability tested - New build | Worst Air Permeability tested - Existing | |
| 1 | 0.13 | 9.87 | 20.33 |
| 2 | 0.22 | 9.02 | 12.72 |
| 3 | 0.30 | 5.98 | 11.28 |
The readings are in m3/hr.m2.
And if you are eagle eyed, you will see that yes, just 2 new homes didn't pass the airtightness test at a Building Regulations level, at least on their first run at it.
The Building Regulations Level is a mximum result of 7 m3/hr.m2.
But of course, a much larger number of new builds had self imposed targets of much less than that, and they did not all reach their targets...now there's another metric to measure this year....
