Our backs are up against the wall.
New wall designs, I mean. Not since the 1970s oil embargo has the design of building walls been changed so radically. But today’s movement is driven less by oil costs and more by strict new energy codes. These prescriptive energy rules are changing building practices nationally.
One result is that architects are driving an entirely new generation of building wall systems.
And unlike the 1970s, which left a legacy of “tight” buildings dripping with condensation, corroded all over and blossoming with mold, today architects benefit from a broad array of pre-engineered solutions.
Driven by codes
The engines driving the train are two baseline building energy codes: the International Energy Conservation Code, or IECC, and Standard 90.1, the commercial energy standard created by ASHRAE, Atlanta’s American Society of Heating, Refrigerating and Air-conditioning Engineers, with ANSI and IESNA. (ASHRAE has a new logo, by the way, which seems to reflects its new prominence — see picture.)
Many architects don’t realize that the IECC adopted, by reference, ASHRAE 90.1. So if you comply with 90.1, you also qualify for the IECC.
That’s a big deal, because the IECC is directly referenced by the International Building Code (IBC) — the de facto building standard for the entire United States. That means everyone has to comply. EVERYONE. And it’s being enforced more and more. In fact, the 2012 version of IBC will ultimately bring these energy-driven designs to every building project in America.
How do the recent changes affect buildings? In many ways, but here are two important examples.
First, since the beginning of time we’ve stuck batt insulation between wall studs, steel framing members, and the like. The new energy regime says OK, you can do that, but it’s not enough. Every building must also have an uninterrupted layer of continuous insulation — the favored acronym is little “ci” or “c.i.” — that is exterior to the framing.
This prevents thermal bridging, which draws heat and cold through structural members to the interior. With c.i., we get fewer hot and cold spots indoors, which is more comfy and easier on HVAC systems. It keeps actual R-values higher closer to what’s stated by insulation makers.
A second major area of change is the air barrier. Air barriers are continuous layers of membrane that prevent air movement from outside to inside a building, a vice versa. They reduce moisture problems and improve indoor air quality (IAQ), but the codes love how they eliminate air leaks — that cuts energy use.
In addition to the emerging code regime, some states explicitly mandate air barriers, like Massachusetts. All federal building projects have to use them. (For more details, visit the Air Barrier Association of America.)
Air barriers can be sprayed on or slathered on, adhered like big high-tech stickers, and even stapled on, like the “house wraps” such as Tyvek behind the siding of houses across the land. (Though putting holes in the air barrier defeats their purpose, I think.)
New total wall systems
One of the most radical and valuable changes caused by the energy code revolution, however, is what I call the total wall system: These are wall products that deliver continuous insulation, air barriers, waterproofing and more. Basically they have everything the commercial wall needs except the structure or the visible exterior cladding, or both.
Examples of these systems solutions come from various places. One is the ICBP concept — it stands for insulated composite backup panel — from companies like Centria, as well as tarted-up insulation products like Dow’s Thermax. Others include Syntheon’s Accel-E, a sort of rudimentary integration of structure and insulation, as well as StoEnergy Guard from Sto (they are a client of my marketing agency), which combines ci plus an air barrier with drainage and waterproofing.
These novel products save the architect a few steps, and guarantee the contractor and code officials that the products are compatible, tested, and work as intended.
Most important, they are designed to meet the new energy codes that are changing how architects build in America — unlike in the 1970s, a change that looks to be permanent.