My associate Abe Kruger and I are the green raters on a set of 18 affordable townhomes currently under construction for the Chattanooga, Tennessee Housing Authority. We were brought in after design and specifications were complete, so we did not have as much influence on the project as we would have liked. Regardless, it is a good project with a very involved and cooperative team. With this in mind we hopped in my car for the two-hour drive up I-75 recently for the first pre-drywall inspection. Not uncharacteristically for the construction industry, they had not completed all the work required for the inspection when we arrived, but they did want our input on their progress and the quality of the work to date. While we will have to make another visit to complete the inspection, it was a productive meeting and we were able to make some much needed mid-course corrections that will help the building perform better and more easily meet the desired certification.
It’s That Damned Batt Insulation Again
As we walked through the first set of buildings, we pointed out some framing cavities that were not accessible for insulation, interior air barriers that needed to be added, and several areas where duct sealing was not quite up to par. The biggest issue by far, however was the inconsistency in the fiberglass batt insulation work, something that I anticipated in an earlier post in this forum. Way back at the LEED design review meeting with the architects we brought up the potential problems with batt insulation that had been specified for the walls. We were concerned that while they had specified closed cell spray foam on the rooflines, and both solar PV and thermal systems, the walls were to have fiberglass batts. We felt strongly that this was not the best decision and suggested that they consider an upgrade to blown in or sprayed wall insulation. We begged, we pleaded, we threatened (well, not really), but apparently we were not persuasive enough to change their minds. As we moved into pre-construction discussions, we made it quite clear that we would expect Grade 1 quality installation, providing the entire team with documents such as the ENERGY STAR Thermal Bypass Checklist Guidelines. We were assured, repeatedly, that everyone involved was on board and there would be no problems with the wall insulation (We were not convinced).
What We Have Here is a Failure to Communicate
As I do at any pre-drywall inspection that involves fiberglass insulation, I donned my handy pair of cotton gloves and started poking around the batts already installed. I cannot say that the installation was anywhere close to the worst I had ever seen, but there was a lot of room for improvement. Some of the batts were carefully trimmed and split around wires and pipes, and others were not. Some fit snugly with no compressions in the stud cavities, others were oversized and crammed in too tight. Gaps in exterior sheathing were inconsistently sealed, and they had not yet even attempted to insulate some walls that were packed with pipes and wires. There were two installers on site, nice, earnest young men who were trying their hardest to do a good job. It was clear, however, that there was a major communication breakdown between the management of the insulation installation company and their field crews, who were not adequately trained to meet the job requirements. We pointed out that while it was quite possible to get a quality job in most of the walls, there were several areas, specifically the walls full of pipes and open web joists at rim joists, that would certainly need to be upgraded to a blown in or sprayed on material to meet the job specifications. Once we were in the field, it became clear to everyone that achieving a grade 1 installation with batts in any framing cavities with unusual shapes or numerous obstructions was going to be practically impossible. The last word we heard was that they were planning to upgrade the complicated sections from batts to a blown in or sprayed on material. We are thankful that this decision was made but disappointed in our own inability to make a convincing enough case earlier in the process.
Getting Priorities Straight
These affordable rental homes are an excellent example of high performance construction, and the housing authority that is building and will retain ownership of them is making many good decisions for the long term. We do feel, however, that it could have been an even better project had they taken a more nuanced look at the building performance characteristics and how they related to each other. While large portions of the budget were devoted to solar systems, wall insulation was relegated to what is essentially a baseline code product that is plagued with installation problems. Obviously they didn’t read my earlier post on outlawing batt insulation.
Get building science and energy efficiency advice, plus special offers, in your inbox.