Following on from the previous rant, this blog post (rant) continues the theme of the problems concerning Building Control in Ireland and focusses this time on airtightness.
The main problem is even though the legislation exists there is no one to adequately enforce it. Ireland is a nation of self-builders, the power to self build is in the blood going back generations when the family homestead was constructed in local stones and timbers salvaged from the sea. There now exists a gulf between how the self-builder constructs and what the Building Regulations require of him/her. This difference is left to be enforced by the supervising architect or engineer as there is effectively no Building Control in Ireland (next rant!). Corners were being cut in the boom time Celtic Tiger Ireland and more corners are being cut now as money has become increasingly difficult to find. It’s only because I’m switched on to airtightness (I’ve done the same course that the contractors would do plus heaps of additional training, passive house courses etc), explain the benefits of airtightness and then insist on the air pressure test being done that it actually happens; my guess is (and remember it’s only a guess) that there’s a lot of self builders who don’t understand the importance of a draught-free house, don’t want the additional expense/hassle and are desperate for the release of funds from the bank that they are trying to get their house signed off without the test.
Don’t forget that you’ll also get a better BER rating when the airtightness test is complete as the result is fed into the DEAP calculation rather than using the default figure of 10.
A minor diversion for a minute: airtightness is the wrong name; a better phrase would be ‘draught-free’. Airtightness conjures the idea of suffocating in your house, stuffy, air-free rooms. A better way to sell the concept is ‘draught-free’ – a house where there’s no freezing cold draughts down the back of your neck in winter. It’s often forgotten that even in the most air-tight house with heat and air recovery; you can still open a window! Opening 2 opposite windows to create an air cross flow will change the entire air in a room in 10 minutes.
The airtightness test is obviously important but the end result requires an air tightness strategy at drawing stage. The way to test your strategy is to place a pencil on a section through the drawing and then draw around the entire envelope and airtight barriers without lifting the pencil once. If you have to lift the pencil (where the airtightness barrier is missing at the junction beteween a window and wall for example) it means you will have an air leak.
My recommendation is to employ an architect that understands airtightness (ahem), a contractor that has done an airtight house previously and has completed a course by one of the airtightness specialists and YOU to go on a contractors course too-you’ll learn a heap and know when the contractor is doing things right (and wrong!)
If you are an airtight membrane specialist such as Ecological Building Systems or Siga, please comment and feel free to plug your wares. As always, comments welcome…
Below are few photographs from recent airtightness test on new, one-off house; first house done by Mayo Contractor that has basic level of airtightness. Current Building Regulations are 10ac/h(which is crap); result after preliminary test (few parts still to fill) was 4.9, still not brilliant, twice as good as building regs but still not low enough (results <3 are forecast in next regulations update).
Notes on photos:
The air test needs to be conducted below a specific wind speed, hence the anemometer.
Door removed and fan blower door installed.
Next rant on Building Control and the lack of it in Ireland, no holding back on this one!
Blog post by iPhone