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30 September 2017 - Passive House airtightness with sand/cement scratch coat

A recent test has come in significantly better than the Passive House standard of 0.6 ACH (@50Pa) for the preliminary test, with sand/cement scratch coat as the main airtightness layer.

We have tested several buildings with this construction method to Passive House standard before, but this result at about 0.23 ACH @ 50Pa is certainly amongst the best.

The main airtightness works apart from the render were done by , Clioma house , which we have mentioned before on this blog - no connection - they just do well.

On this site, some works had already progressed before Roman and his team could get going - so some of the details look less than ideal at first site, but it certainly proves itself under test. Of course, the site management is also very important, so well done to Alan Tyrell of Ballinlough Construction for keeping the other trades under control.

Some of the details that go into such a good result - some of which are due to having to catch up with site work that had sped ahead....
Corner showing two Sliding sash windows Sliding Sash Example Sliding Sash Example

25 May 2017 - Passive House airtightness with sliding sash windows

Greenbuild has recently been pleasantly surprised by a house with many sliding sash windows testing significantly better than the Passive House standard of 0.6 ACH (@50Pa) for the preliminary test.

In this new home, the Munster Joinery triple glazed sliding sash windows make up about a third or two fifths of the glazing, the rest being various other Munster Joinery products.

Yes, the windows leaked a bit, but far less than we expected.

The house is a timber frame house produced by Shoalwater timber frame , which we have mentioned several times before on this blog - we have no connection to them apart from testing for them - but they just do very well, every time!

Examples of the sliding sashes in place- despite which passive house airtightness levels are still being acheived
Corner showing two Sliding sash windows Sliding Sash Example

02 May 2017 - Large(er) Building airtightness Testing

During 2015 Greenbuild was the first testing company to be audited by NSAI for the new category of airtightness testing using 'multi-fan' equipment.
This allows us to use more than one standard blower door fan in an airtightness test.

The non-domestic Part L of the building regulations are currently up for review - and the proposal is that non-domestic building airtightness testing may become a requirement in Ireland in the next few years, at levels of 3 m3/hr.m2 and 5 m3/hr.m2, based on the building size.

If the building is relatively small - say the size of up to maybe 4 'standard' semi detached houses, or up to an envelope of about 2000 m2 and fairly airtight - say no more than about 3 m3/hr.m2, then actually many of the registered testers will be able to test with one fan as per the NSAI registration - including ourselves, and do please give us a call.

However, if the building is larger than that, or leakier than that, then several of the standard fans may be required, and we have noticed a small upswing in request for this type of testing - if you are a building owner/builder or another airtightness tester that has jobs coming in that you can't service as you don't have the capacity, then please give us a call to discuss.

Some examples of larger buildings tested by Greenbuild
triple fan set in place double fan set in place example of school that Greenbuild tested example of warehouse that Greenbuild tested example of school that Greenbuild tested example of four fan set up

24 April 2017 - Downlighters and airtightness

Downlighters are often a source of considerable air leaks in a building. They can be a primary leak, say where they are installed into a roof space open to an attic that is open to outside, or they may be a secondary leak, where they are in a void that should be sealed, but isn't, such as the space between upstairs and downstairs.

When advising on airtightness, we would often recommend fitting downlighter hoods on accessible downlighter, where a sealed box or pot is placed over thelight, with enough space for some air circulation (but not infiltration!) around the back of the units. However, in many cases there is no access to the rear of the unit as they are in these intermediate floor voids or sloping ceilings.

We recently did some testing for Sean O Sullivan of Northarc Builders in Kildare, who could not use hoods or pots on many of the fittings, so he used wet room sealed downlighter units, plus simple nice finishing around - the result is neat and works well for airtightness.

Well finished downlighter Even with many downlighters, an airtight finish
well finished downlighter several downlighters in ceiling - good airtight finish nonetheless

30 January 2017 - 2016 in Airtightness

Just for interest: the best and worst tests of the year in 2016

Best Air Permeability test Worst Air Permeability tested

New build

Worst Air Permeability tested


1 0.27 9.44 13.78
2 0.32 (twice) 8.80 13.67
3 0.33 8.62 13.58

The readings are in m3/hr.m2.

What is interesting here is that the 3 best results are all from one site, the three worst results are also all from one site!

The other numbers, for existing houses, are all surprisingly close also, even though they are different houses. Unfortunately for the home owner, the worst result was a recently renovated house where a complete refurbishment was undertaken, but the heatability after refurbishment of the home was not what the homeowners expected, so Greenbuild was called in to try to diagnose the problem.

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Airtightness testing - IS EN13829:2000 Certified

Greenbuild Energy Rating and Building Information Services Ltd trading as GreenBuild
Gorey, Co. Wexford
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