Modern Houses - By MHM Contributing Staff on Saturday, April 25, 2009 - 0 Comments
A Modern House
Dublin architects show off A House.
Dublin Architects FKL say their basic approach for all projects begins and ends with an appropriate application of materials determined by a site analysis. As reported in Dezeen, A-house “is an exploration of the possibilities of integrating environmental concerns at the fundamental level within a contemporary idiom.”
Unfortunately we don’t get many details from the architect about actual environmental methods or technologies used in the design, but the location at least was chosen for “proximity to schools, local shops, recycling facilities and work,” so if you’re looking for environmental credentials in A-house, all is not lost.
At the very least A-house is an interesting study in spatial manipulation considering the “slipped tube” layout where concrete provides the structure and windows are strategically located to pour light into the house in the right amounts for each type of room.
The rough materials such as sandblasted concrete exposed to the interior won’t fit everyone’s taste, but seems to work well with the chosen timber. Large enough for a family of five A-house is also designed to be suitable over a lifetime. Read post in Dezeen Magazine.
Update 4/29: In the original MH Mag post above we remarked about the lack of information in the Dezeen post regarding environmental methods used in the construction of A-House. The architects followed that up by contacting MH Mag and providing the following rather detailed accounting of environmental savvy techniques employed during the construction process.
While it’s a bit long we are publishing in whole the information provided from the architect. It’s really the least we can do for someone who (obviously) takes such care and pride in their methodology.
From FKL -
Environmental Design by Ramsay Cox & Associates
FKL was advised on low-energy design, throughout the design and construction stages. The house has been designed to achieve an A-Rating using the DEAP Methodology, with particular emphasis initially being placed on the improvement of the passive elements of the house. The house is based on a model of heavy mass to absorb and retain heat, wrapped externally with a highly insulated skin.
Insulation levels were increased substantially beyond the levels required under Part L of the Building Regulations with u-values for the Floor, Walls and Roof being reduced to 0.1, 0.14 and 0.1 W/m2K, compared with Part L requirements of 0.25, 0.27 and 0.16 respectively.
The concrete rising walls are thermally isolated from the slab using Schoeck Novomur from Contech, ensuring a continuity of the insulation zone wrapping the concrete structure and avoiding thermal bridging at this important junction. Architectural details were developed to eliminate thermal bridging at all other important junctions, including the wall/roof junction and window junctions. The bespoke architectural glazing was designed in collaboration with the main contractor to maximise the air tightness of the envelope, a requirement compatible with the mechanical ventilation heat recovery system.
The significant reduction in the primary energy demand of the dwelling achieved through the passive measures allowed for a number of solutions to be considered, with a reduced capital outlay achievable, the client proceeded with our recommendation to install solar thermal water heaters, mechanical ventilation heat recovery -an MTD 300 unit from Ecoliving-, with a Sebuk Band-A Rated high-efficiency modulating condensing gas boiler as back-up for colder periods. The installation of under floor heating throughout the dwelling controlled by individual 7day room thermostats ensures that the boiler always operates at peak efficiency. Appliances are A-rated and lighting is by T5 energy efficient fluorescent lamps with tungsten correction filters, and an induction hob has been used to further reduce electricity use. Provision has been made in the design for the future incorporation of a biomass-fired stove within the main living space, and also for solar photovoltaic panels for on-site power generation to cover the constant power drain of HRV, fridge and pumps and to improve the energy rating and carbon emissions further.
Structure by John Casey, Casey O’Rourke Associates
As the design called for the majority of the house to be exposed reinforced concrete internally and with the objective to achieve a structure with a low embodied carbon content, the specialist subcontractors, Uniqrete used self compacting concrete with 50% of the cement content replaced with GGBS (also known as Ecocem). This is the maximum percentage replacement allowed for structural items but non-structural elements have 70% of their cement content replaced.
The plywood formwork was reused a minimum of three times. The release agent that was used on the formwork was a vegetable oil based product to reduce staining on the concrete but also to ensure that it was biodegradable. The sand for the sand blasting of the concrete was reused as blinding under paving externally and recycled crushed stone was used as hardcore throughout.
To achieve a sustainable design, the most economical use of materials is essential and therefore a finite element analysis was carried out on the structure to ensure only the minimum reinforcement steel was used and structural walls were kept as thin as possible. To maxamise space, steel column sections are introduced at ground level to support the cantilevering slab and wall overhead. At the upper level, reinforced concrete walls double up as deep concrete beams (which cantilever) to ensure that economies are achieved in the design.
All rainwater that falls on the house is collected and directed to the rear garden where it is used to irrigate the planting. There is no discharge of any rainwater from the site to the public sewer, which is compliance with the principles of SuDS (Sustainable Urban Drainage Systems). Paving is designed in separate panels of GGBS concrete with gravel and planting in between, to allow for absorption of surface water runoff .