Dr. Mohamed Al-Hussein, PHD, PEng, Associate Professor - Construction Engineering and Management, University of Alberta
House Work – Prefabricated Building Industry
U of A civil and environmental engineering professor Mohamed Al-Hussein wants to put the “pre” back in “prefabricated” as a way of greening the housing construction industry. Although the prefabricated building industry - which prefers to refer to its products as being built “off-site” - has been operating for decades, Al-Hussein thinks it’s time that more builders did away with all that wasteful, arbitrary and inefficient on-site framing, wiring, plumbing, drywalling and painting that generates a haze of greenhouse gases.
“All that material, all those trucks and people coming and going every day,” says Al-Hussein. “Estimates are that building a home between 1,200 and 1,600 square feet generates about 55 to 100 tonnes of CO2, while also heating a home while it is being built (to keep temperatures optimum, not just for the workers, but for things like drywall compound and paint) can generate another five tonnes of CO2 a month. We think we can cut that in half.” Al-Hussein and his team have been working for the last couple of years on computer-assisted design and other artificial intelligence software they’ve been developing to streamline the house-building process. The “parts” for the house are made in an off-site factory and then assembled on the foundation that’s been poured for the house. The goal is to cut the construction time by more than 60 percent while reducing home construction costs by 20 percent.
“We’ve got it to about 30 homes a month and capacity to go to 40 or 45, though demand for new homes has slowed a bit recently here,” says Al-Hussein. On-site vs.Modular re: the North Ridge Place Seniors’ Residence, St. Albert Dr. Al-Hussein analyzed the CO2 impact of modular verses conventional construction on-site construction of the North Ridge Place Seniors’ Residence, St. Albert. His conclusion stated “In summary, modular construction compared to on-site construction results in a scheduling savings of 55% and a 43% reduction in CO2 emissions. Conventional construction results in 14.3 months and 98.9 tonnes of CO2 emission,s while modular construction takes only 6.03 months and results in 56.3 tonnes of CO2”.
Construction & Energy Efficiency Features
Our homes are designed to maximize energy efficiency as well as making them as strong as possible for transportation.
All of our exterior wall sheathing is glued and stapled to the studs and belt rails so there is no exterior sheathing that is not supported by framing. The sheathing also laps the floor framing and perimeter of the roof.
The standard framing is 2x6 on 24” centers and most windows fit between standard framing centers so there is no need for extra studs, which allows for more insulation.
A special exterior wall stud design allows the installation of windows and doors without the need for extra studs or headers.
The header detail makes it possible to insulate the header thereby reducing thermal bridging.
The exterior wall header detail also allows us to move roof trusses around as necessary without adding additional wall framing.
The structure of the home is designed to withstand snow loads far in excess of the snow loads in most areas in Alberta.
The interior of the exterior wall is designed in such a way that the gyproc is glued to the belt rails while still providing a continuous vapor barrier.
All electrical boxes are wrapped with a vapor barrier and then all wires are fasteners are sealed with caulking. All penetrations in the walls and ceiling through the vapor barrier are sealed with caulking as well.
All of these unique features create a very tight structure and a more energy efficient building.
Our standard insulation is R40 in the roof, R20 in the exterior walls, R26 or R33 in the floor depending on the floor framing types. We do have available insulation options that are as high as R52 in the roof, R22 in the exterior walls and R52 in the floors of self contained truss floor homes. Other insulation options could be available upon request and depending on the type of home.
Our standard window is a double glazed Low E window that is rated at R3. Most other people use a window that is rated at R2. We have an R9 window available in some of our products as an option that has an energy performance 300% better than our standard. In most cases, this could reduce energy consumption for a whole house by about 50%.
Our truss floor houses are built with a built up perimeter beam that allows the installation of the home on a basement without the need for an extra built up beam in the basement.
We strive to not only meet but exceed the requirements of the Canadian Standards Association and the National Building Code.
Modular Homes are Naturally Green Brochure
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