Rethinking the boxBy Tom Owens on 03/06/2012
Builders who have been fortunate enough to stay busy over the past few years have had to rethink the way they run their day-to-day operations — to re-evaluate what they do and how they do it. Panelized wall systems, built within the controlled environment of a manufacturing facility, are a great first step in creating a more efficient, affordable and sustainable method of home building. The idea is to move redundant job-site tasks into a controlled environment to minimize waste, maximize efficiency, neutralize weather issues and make a quantifiable process of material recycling into a priority.
While our lives are influenced by technology in virtually every way, the home-building process is generally the same as it was 200 years ago. The home-building industry as a whole needs to look to the empirical data gathered through building science rather than relying upon tradition to move the industry toward a more sustainable and more efficient future.
Traditional building practices are full of unnecessary redundancies and conventional job-site construction is terribly inefficient and wasteful. On typical construction sites, up to 30 percent of raw building materials — including wood, metal, glass, rubber, petroleum-based materials, cardboard and paper — often end up in landfills. The industry lacks building-material recycling programs, suffers inefficient deployment of carpenters and subcontractors, and sees very poor quality control. Conventional construction workers seldom receive benefits, and workman’s compensation insurance premiums are three times as high for site work as for shop work.
Panelized wall systems take the layout, cutting and pre-assembly of site-built stick-framed walls and puts it in the controlled environment of a manufacturing facility.
Building wall systems in the “shop” allows for increased efficiency, minimal waste and working with more precision, all while keeping the materials (and workers) dry and not exposed to the elements. An artisan-driven manufacturing facility can produce full 2-by-6 walls, framed with advanced techniques in which windows and doors are installed in a fraction of the time it takes to do the same tasks onsite. This complete wall system can be delivered to the job site without insulation and fitted onto the foundation via crane, ready for the electrical and plumbing contractors to do their work the way they are used to doing it.
The parallel methodology of panelized wall construction to traditional timber frame construction is interesting. Once the design of a timber frame home is finalized, the cutting of the entire frame, including all joinery, is done in-shop. The precision cutting necessary for proper fit and structural soundness requires a controlled, indoor environment where craftspeople can measure twice, cut once, and sharpen their tools as necessary in a day’s work. Following the natural progression of timber frame production, a crew can plug into a panelized wall system of fabrication and produce all the walls necessary for the home in the controlled shop environment.
This “value added” framing system marries perfectly with a Structural Insulated Panel Association-certified roof system to quickly and efficiently get a home dried in quickly and with much of the exterior work completed prior to delivery on site.
The fact is, reducing material waste and the costs associated with on-site labor will reduce the overall cost of building a home. It will reduce the builder’s tipping fees, reduce labor and fuel costs associated with hauling waste and employee commutes, and reduce insurance premiums. Centralizing wood cutting operations in the facility promotes wood reuse, which can reduce wood waste by 15 percent. The in-shop environment also protects materials from deterioration and exposure which helps mitigate any trapped moisture related issues that can occur when a site built homes framing and subfloor is exposed to the weather for any length of time. And it allows us to choose products with little or no packaging and use durable, locally produced, recycled content materials and finishes where available. A stable, in-shop environment helps ensure a correct amount of material is delivered at the appropriate time and integrated into the structure with precision and maximum efficiency.
It is a big step down the path toward affordable high performance housing. Panelized wall systems are the beginning of the transition phase of homebuilding. Encouraging their use supports an overall sustainable green building strategy.
Tom Owens is the owner and designer for High Country Timberframe, and the designer of the HCTF ShopBuilt Panelized Wall System. A timber-framer and fine woodworker since 1984, he has been a regular contributor to “Sukiya Living” regarding traditional Japanese carpentry. His furniture is featured in The Custom Furniture Source Book, A Guide to 125 Craftsmen, published by Taunton Press. He can be reached at .