Wednesday, February 23, 2011

Windows and Openings at Denby Dale Passive House

The next video in the excellent series by the Green Building Store on the Denby Dale Passive House looks at Windows and Openings.

Some of the innovative features was the use of the triple glazed, argon filled Ecopassive timber windows consisting of a thermally broken frame giving a whole window u-value of just under 0.8W/m2 K and a glazing u-value of 0.6W/m2 K. The use of the plywood box for easy and accurate positioning posed some challenging airtightness details especially at the plywood box / blockwork and plaster junction and the window / plywood box junction. The use of Pro Clima Contega and Tescon Profile tapes hepled to provide a novel solution in both cases. Thermal bypass was addressed with the use of the aluminium cavity closer and the door threshold required the construction of a moulded fibreglass box section filled with polyfoam insulation.

Wednesday, February 16, 2011

Passive House Foundation Systems

Last week we looked at some of the different types of foundation systems being used in the design and construction of passive houses in Ireland and the UK. According to the current 2008 Technical Guidance Document Part L, the recommended average elemental U-value for ground floors is 0.25W/(m2K) for floors with no underfloor heating (UFH) and 0.15W/(m2K) for floors with UFH. The first value is due to go down to 0.21W/(m2K) with the implementation of the 2010 revision in the near future. So we can see that the building standards are moving towards the passive house standard of between 0.10 to 0.15 W/(m2K) for ground floors. Interestingly, Viking Homes discusses the effects of cold bridging for floors designed to meet the 0.25W/(m2K) target and how the actual figure can be considerably higher (see below).

This reinforces the passive house approach of providing a continuous thermal envelope with excellent airtightness and minimal thermal bridging. The Department of the Environment, Heritage and Local Government has provided some guidance on this with the publication of the Acceptable Construction Details and airtightness and insulation continuity guidelines. This focus has promoted some innovative approaches to foundation designs from Viking Homes, Aeroboard, Passive House Builders and the Green Building Store in the UK (see video below).

Friday, February 4, 2011

Latest Construct Ireland Magazine January 2011

The latest issue of the excellent Construct Ireland magazine is a passive house special focusing on some interesting projects including a low energy upgrade and extension in Stillorgan and a Rosslare passive house scheme.  The feature article provides an example of biomimicry in action with a focus on how termites can influence green building design and construction.

Wednesday, February 2, 2011

Links update on SitePass Blog

A number of links have been posted on the SitePass Blog (at the bottom of the page) to provide a general resource for those interested in Passive House Design and Construction.

Tuesday, February 1, 2011

First Steps Passive Article - Example of Blog Contribution for M.Sc. students

In the article 'First Steps: What can be a passive house in your region with your climate?', Wolfgang Feist  of the Passive Institute in Germany, advises that passive house details must be specific to individual climatic and geographical regions especially considering the local building traditions and climatic conditions. He highlights examples of applying Californian passive solar design principles to buildings in central Europe resulting in buildings which were designed for large solar gains that did not exist.

He proposes that the 'Zero Energy House' concept would add an unacceptable cost to a project as he sees no extra benefit being gained by increasing efficiencies beyond the 10W/m2 target. He maintains that the environmental impact is minimal even considering the use of fossil fuels including oil, gas or coal as the energy demand is so low throughout the lifespan of the project.