Back to the future

A 1950s semi-detached house in Monkstown, Co Dublin, has had its Building Energy Rating (BER) reduced by 90 per cent, becoming the first building in Ireland – and fifth in the world – to be certified under the Passive House Institute's EnerPHit standard for retrofits.

The BER rating for 29 Wynberg Park has been raised from a very poor G to an impressive A3 thanks to Joseph Little Architects, who specialise in energy efficiency. The results will be presented at the 17th International Passive House Conference in Frankfurt tomorrow.

Homeowner Pauline Conway, who had spent her childhood in a house without piped water in rural Ireland and 13 years of her adult life working in African countries, wanted her Monkstown home to be an example of “genuinely sustainable retrofit”, according to Little.

The project involved retrofitting the original house (101sq m/1087sq ft) and building a south-facing extension (58sq m) at the rear while ensuring that it would continue to fit into its suburban context, with small elements such as a Juliet balcony suggesting something special.

"For instance, new clay bricks from the same source as the 1950s bricks on the lower half of the front elevation were cut down as slips to clad the new external wall insulation, ensuring the completed house continued to complement its attached neighbour,” Little says.

A south-facing extension that curves away to make space for outdoor dining, “sun pipes”, rooflights, windows turned into patio doors, a glass screen between hall and kitchen and an open riser stairs with glass balustrade all contribute to even light distribution.

The architects chose low- carbon materials – timber frame, cellulose, woodfibre, eco-cement and external wall insulation – and water conserving taps, bath and cisterns along with an innovative, indoor, gravity-fed rainwater harvesting system.

Services include a high-efficiency mechanical ventilation system with heat recovery, which means that the house has only three wall-mounted convector heaters and two towel radiators, making it a “comfortable, healthy place to be”, with minimal heating requirements.

“Deep retrofit is the near future, but we still have a lot to learn. Poor orientation and construction methods, old rising walls, intermediate floors and decorative features of a bygone era all complicate the works and impinge on the performance of energy-efficient retrofits.”

Little agrees that external insulation projects done in a piecemeal fashion often result in individual houses being treated differently side- by- side, with the (avoidable) loss of architectural features such as string courses and patent reveals making them look drearily blank.

“Done badly, external wall insulation can devalue a property and cause a district to lose its character,” Little told a recent Energy Action conference on fuel poverty. But there were “few rendered details that a good contractor using the right systems can’t faithfully replicate.”

He suggested identifying all cement-rendered terraced houses in suburban areas of Dublin – such as Cabra, Crumlin and Finglas – and doing them in batches to achieve economies of scale, but with a brief to replicate architectural details to avoid loss of character.

“It is not acceptable that, in the cause of energy efficiency, we lose key aspects of a sense of place that make suburbs identifiable. Upgrading whole terraces can allow better quality work and maintenance of the features that made these areas memorable and unique.” Issues such as these will be discussed at the second Better Building conference at Croke Park next Wednesday, April 24th, when participants will be looking at passive low-energy housing, deep retrofitting, green building materials, public procurement and sustainable communities.

betterbuilding.ie