Maximize your Builder’s bottom line through Energy Efficient design (Part III)
In Parts I and II we talked about design rules that address both environmental sustainability and how to manage the shift in homebuyers’ expectations in terms of Energy Efficiency. We also indicated that certain design rules should be “non-negotiable”; especially ones that affect indoor air quality, home comfort and energy-efficient design and gave concrete examples how to achieve this. The main key to this is the on-going design review process. In this part we will continue with concrete suggestions for a value-engineering program and how to translate this information through your construction drawings.
Now that you’ve sold your builder on the merits of energy efficiency and building a value-added product, you need to be able to answer this question: “How am I going to sell a house which costs more to build in a price sensitive market, especially when the guy across the street is selling code-built houses?” The answer is to reduce your builder’s construction costs. The code-built house across the street is not really “code-built”; it is “over-built”. The framing package is the largest recoverable cost in the house building process. Although some framers will tell you that any stud spacing greater than 16” o.c. will certainly cause the house to fall down, OBC tells a different story. On a two-story house, all 2×6 walls can be framed at 19.2” or 24” o.c., as can all NLB 2×4 walls. ENERGY STAR and LEED-H both recognize this and give credit for using less lumber.
Some basic value engineering principles:
Increase stud and joist spacings to either 19.2” or 24” o.c. The problem: resistance from framers telling you the house will fall down and builders will tell you that the buyers will perceive them as “cheap”. A common callback is nail-pop repairs, however; using less lumber will result in fewer lumber related callbacks.
Layout floor systems to benefit HVAC designs, either front to back or side-to-side.
Remove all drywall backing below truss roofs. This will eliminate problems associated with truss uplift; drywallers must use drywall clips. The problem: resistance from framers and drywallers.
Review all lintel sizes. Are you using two 2×12’s (or LVL’s) as the garage lintels to pick-up 24” of roof; a three-ply LVL as a stairway header; LVL’s as porch beams when a two-ply 2×10 will do; or a standard 2×10 window lintel whatever the opening?
Review tall wall details. This is probably one of the best examples of “over-build”. Have your engineer review these details and work with the municipalities on an acceptable alternative to framing a wall at double 2×12’s at 12” o.c. with blocking at 48” o.c.
Review dimensional roof framing details. If trusses are spacings are at 24” o.c., why spec conventional framing of non-truss components at 16” o.c.?
Conduct an “as built” frame-walk / drawing review with framers, site supers and the lumber supplier to verify the design changes and update the drawings as required.
The solution: Educate your builders and trades! Ask the builder to compare the costs of the new take-off versus the old one. Also ask the builder if the waste removal costs have changed as less materials = less waste.
The more information you can provide on your construction drawings, the better the construction process. Trades look for and need more direction to complete their jobs satisfactorily. Take the imagination out of the building process and replace it with a standardized formula. This will reduce costs, trade inconsistencies, PDI deficiencies, callbacks and homeowner complaints. The designer / architect is the most reliable source for standardizing the construction process. Some suggestions are:
Update the construction specifications to reflect your changes. These changes must be updated for permits.
Work with the HVAC designers and include HVAC layout on the construction drawings.
Consider marking plumbing and electrical layouts on the construction drawings. This will give the framers much needed direction and also standardize the installation process. A standardized process = reduced costs, less materials and improved quality.
Provide drawing details of air barriers, tall walls, even dormer gable ends to standardize these details.
Revise drawings as required and include a revision date so the site and trades knows which drawings are the most current ones.
Work with your Builder to ensure that the drawings reflect the most current trade scopes of work.
Working closely with your builder / client may initially require more time and energy however, it is a winning recipe for sustainability and success: for the homeowner, for the builder, for the environment and for your company.
Al Schmidt is a building and energy consultant and trainer for EnerQuality Corp., a service provider for the R-2000 program, ENERGY STARâ for New Homes, Building Canada, LEED-H, GreenHouse Certified Construction and EnerGuide Rating System. EnerQuality has been in the business of promoting “best building” practices in Ontario since 1998.