Week 4 Foundation Systems Post-Lecture Resources

In today's class, we looked at a number of different systems available for foundations, rising walls and ground floors. Energyquarter.ie have produced an excellent video on this highlighting the importance of thermal bridge free design.

 

Some of the products mentioned by Tomas O'Leary to minimse thermal bridging included an aerated low U Value block e.g.  Quinnlite block (as used by Viking Homes). Another interesting element was for the insulated cantilevered solution for balcony construction. Foamglass was also introduced as a viable thermal break alternative to a standard block rising wall construction. We then looked at the Denby Dale project in the UK, which used traditional construction techniques to achieve the passive standard.

The 3D model was developed by Gerard Nicholson as part of an architectural competition we held in the Department of Building and Civil Engineering over the summer (2011).

Week 4 Foundation Systems Lecture

Following on from today's class, please find the presentation in Prezi for your viewing pleasure!

Week 4 Foundation Systems Pre-Lecture Resources

This week we are going to have a look at the different foundation systems on offer for a passive house approach. Interestingly, the recent revision of the Part L 2011 for residential buildings has reduced the elemental u-values for ground floors as outlined in Table1.

Table 1 Maximum elemental U-value (taken from Technical Guidance Document Part L 2011)

 

Where the source of space heating is underfloor heating, then a U-value of 0.15W/m2K should be satisfactory (Section 1.3.2.2 from Part L 2011). From a thermal bridge viewpoint, Part L recommends referring to the Acceptable Construction Details and the guidance on limiting thermal bridging and air infiltration provided by the Department of the Environment, Community and Local Government. A number of companies have developed some innovative solutions to providing a foundation with little or no thermal bridging, good air-tightness and good overall energy performance. Viking House and KORE have developed the passive slab which can deliver a U-value of 0.08W/m2K. Passive House Builders have developed their own solution (click into foundation to see detail) which has been successfully used on certified passive houses both in Athenry and Oranmore in County Galway. Aeroboard also provide the Supergrund system for passive house construction.

We will have a look at these systems as well as a few others on offer this week in class.

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).