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Co Cork renovation – airtightness and ventilation are key components for success

Mick Kiernan employed the principles of low energy building to renovate his home in Clonakilty, Co Cork to become a warm, efficient and healthy building. The transformation of his detached 1970s bungalow from a cold and draughty property to an energy efficient home with airtightness close to the Enerphit standard was achieved by being systematic about problem solving.  “A lot of the problems people would have renovating were problems I also came across” says Kiernan.

When he bought the property in late 2003, Kiernan was aware it came with many problems. It had an old boiler, leaking copper pipework, and poor insulation, airtightness and ventilation. Kiernan now believes that it was the poor airtightness which meant it was difficult to heat the house to 17C or 18C, even when he had the heating system on all the time. Kiernan carefully measured the before-and-after effects of the major work done to his house.

By 2005, he had figured out what he wanted to do, this included: new plumbing, the relocation and replacement of the oil boiler with a more efficient one, the replacement of all radiators and valves, new ceilings, and an extensive upgrade of the heating controls. “The following winter, the house went from being unable to be heated past 17C or 18C, to heating up to a comfortable temperature in 30 minutes”. But Kiernan soon became aware of the house’s poor indoor air quality. “I realised that the building was largely under-ventilated and so I started to research ventilation systems”. He decided to install a mechanical ventilation heat recovery (MVHR) system from Irish manufacturer Proair, which greatly improved the indoor air quality.

Kiernan subsequently spent a lot of time trying to find a contractor who could deliver what he wanted. “I have lost count of the number of so-called low-energy builders I interviewed who didn’t understand the concept of a thermal bridge, airtightness or building physics.” In the end, Kiernan met contractor Tim O’Donovan of Sustainable Building Services at an NZEB event in 2013. The buildings O’Donovan’s company has constructed have achieved some of the best airtightness results in Ireland.  O’Donovan says: “It’s the old adage of do it once and do it properly so you don’t have to go back, and Mick was very much of that mind-set, which is fantastic.”

O’Donovan originally received his training in airtightness and low energy building from SIGA in Switzerland.  He then trained his construction workers and sub-contractors in the principles of low energy quality building. “The advice I would give to anyone trying to achieve airtightness on site is attention to detail” said O’Donovan.  His experience has taught him that “from the outset you need to have a clear plan for the building, focussing on both airtightness and wind tightness.  For example it is important to include in your plan the ventilation system.  It affects the overall airtightness of the building if you install the ventilation afterwards as a result of having to puncture the membrane”.   O’Donovan, who uses the breathing wall system for new builds, believes that education is the key to improving quality in the construction sector in Ireland.   “Site workers need to understand the implications of the building regulations.  The Part L standards are getting more onerous; we should be aiming to get our buildings from 7 air changes per hour down to 3 air changes”.

The building fabric works on Kiernan’s house began in July 2014, and went on for six months. O’Donovan installed new clay tiles and a SIGA wind-tight breather membrane to replace the old felt and concrete roof tiles. The floor of the cold attic was insulated with cellulose insulation above the existing joists, and the new external wall insulation was carefully installed to rise up to meet the attic insulation.

So after all the renovation work and the monitoring of this project what is Kieran’s verdict? “The general feeling of comfort in the house has improved significantly with very little energy input. When all the data is compiled I would not be surprised to see a reduction of at least 65% in the usage of oil from before the retrofit, and more than 90% reduction from when we first moved in in 2003. Most significantly our stove has become largely an ornament!”

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