Tuesday, March 1, 2011

Case Study, Blog Assignment 1.

This case study is based on a Passive House which was the first to be constructed and certified in 2009 in the ile-de-france region of the country. The house is located in a town called Bessancourt which is situated around 28km from the french capital Paris. The house was designed and constructed by Karawitz Architecture and not only meets the passive house standards but also adhere's to many sustainable guidelines.

North Elevation (inhabitat.com)

Aesthetically the structure is an abstract replica of a traditional house which drew inspiration old barns which would be quite common in the part of France in which it is situated. The entire structure is created from the assembly of large solid wood panels which were prefabricated off site. The unique second skin of the building is one which is not commonly seen in construction as a whole. This skin is made from untreated bamboo which envelopes the solid wood frame, passing through the windows to the north and finishing by unfolding onto the roof. To the south of the structure identical bamboo shutters are fitted onto the large open bay windows providing both shade and light, during both day and night. This cladding over time will eventually turn a grey colour and not only helps in reaching the required standards but in also adding a sustainable element and natural look to the overall building. In terms of the overall cost of the structure, according to the Passive House Institute data base the figure was nearly €290,000. This price in terms of buying a house in this region at the same time is very advantageous, with the passavie house coming in considerably cheaper.

Bamboo Outer-skin Layer (solarpedia.com)

The structure has a floor area of 161m sq and has only one concrete element in its make up, that being the ground floor slab. External wall construction as mentioned before is made up of two layers, compromising of the bamboo skin and hard wood panels. Along with this there is an under roof membrane, wood fibre insulating boards along with an airtight steam brake which all aid in insulating and improving air tightness in the structure. When looking at the different U-values of this building it can be seen from those given on the passive house data base that they are a little bit higher than those of Ireland’s first passive house which was built in 2005. However even though this is the case the heat load of both structures is calculated at 13 w/ (m2). In terms of the primary energy requirement which is required to be under 120 kWh / m2a, this building comes in at 90 kWh / m2a in comparison to the Irish example which has a lower requirement of 76 kWh / m2a.

South Elevation (inhabitat.com)
While it is important to compare these two types of structures as they come under the same classification it is important to take some factors intp account when comparing. They are both certified passive houses but are both completely unique designs which have been constructed using completely different materials and are both operating in very different climates. I do however think that this passive house in Bessancourt has included an aspect of sustainability which up until now has not been seen very often in the passive housing area.


  1. Very interesting choice Shane, the use of bamboo is very unusual and different. What you have highlighted here is the completly contrasting construction designs for two completly different areas with regards climate extreams. I would be presuming that this area in France, it would be more priority to reduce solar gains & glare compaired to Ireland, where designers are always trying to increase solar gains, where reductions in space heating is the aim. Just in relation to the foundation type, is it a concrete strip/raft?

  2. Hi Shane, With the bamboo shutters providing shade and solar gain is the fact that they are manually adjusted going to impact on the internal heating and cooling. Say for example if they are closed over on a warm day and the occupant goes to work the next day without opening them the house will lose out on solar gains during the daytime peak. The reliance on the occupant to control the solar gains and shading accurately would be hard to guarantee. People still have trouble turning off lights!!:)

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  4. Thanks for the comments guys.. yes i chose this example of a Passive build as i thought it was a very unusual build which embraced the element of sustainability which is so often over looked in this building method.

    In terms of the foundation Martin, in the research and articles which I used to compile this blog the foundation wasnt very well documented but seeing as its timber frame with no blockwork it would be very unlikely that it would be anything other than an insulated slab foundation. In answering your other query i think many would assume the same..as in the problem would be cooling the house instead of heating. But the challenge of heating the building in even this warmer climate still exists, but the identical shutters cover the large picture windows on the south, which helps in creating light and shadow during the day or night. I think that the bamboo here works very well as a shading element when required to so which could be the case here if it was a very warm sunny and there could be a chance of over heating.

    In respondance to what you are saying Sean I think it is a very valid point and the fact that the bamboo shutters are manually adjusted leaves room for human error. I think that in an ideal world the best practice here would be to have small mechanical arms operated by some kind of sensors be that light or heat, which could signal when to close or open the shutters. I think the idea is right but operation of it needs to be perfected.

    I do however think that this kind of thinking is the way forward and a way of improving the overall performance of the passive house. And although it has not been perfected yet, the fact that this house is in fact an energy plus house because of the pv panels on the roof and the fact that it tries to embrace sustainability means it is certainly the way forward.