Sunday, November 8, 2009

Summer 2009: Vaulted Ceilings Saga continues

So the weekend before the roofing crew was to show up, I needed to create roughly 16 pieces of 4'x8' decking, covered with radiant barrier foil and properly spaces baffles, to be ready for the job the following week.
As luck would have it, illness struck that weekend, but even in those early days, I knew that Energy Efficiency would wait for no man(!), and I toughed out the job of moving those rather awkward pieces of decking around and working on them. The job was made easier by the fact that the radiant barrier was already 4' wide, making it a matter of a single measure and cut operation to get the barrier on each piece. To cover 8' of length with baffles required 4 baffles per decking piece, but again, that was fairly simple and required mostly eyeballing with a little measuring.
Finally, it was the next week, and the crew arrived. I couldn't sit inside and just hope that the new decking was installed properly; I had to go out and see it. Although they wouldn't let me up on the roof, I was able to assist with a few things like cutting decking for odd-shaped areas near the corners of the roof, and creating 2 or 3 more pieces of radiant barrier decking since the original estimate had been a little low.
Preparing to staple baffles to a new piece of decking

The roofing crew was quite competent, and despite the July heat they completed the job in a single day. My hat is off to them for their professionalism in dealing with a job that had a few more components to it than usual. Here is a shot of one of the last pieces going on to the back roof. The baffles and radiant barrier are facing down, of course, but they are there. You might be able to tell that we had to go two 4' widths in from the outside wall to make certain we had enough length to cover the vaulted ceiling portions, as well as to get above the level of insulation in the attic so that the open end of the baffles inside the attic would be clear.

Later that night, it was clear that the new barrier had helped, although the change was not as dramatic as adding the initial barrier; after all, we were adding roughly 600 square feet to an already existing 1500 or so square feet. Significant, but not as much as going from 0 to 1500 square feet the first time.
This improvement yielded us the following benefits:
  1. 600 square feet of radiant barrier
  2. Far better barrier coverage over the master bedroom (from 70% to 100%)
  3. Significant improvements to the intake ventilation
  4. 600 square feet of new decking to replace worn (admittedly still functional) decking
The overall cost was around $700, $540 for the plywood decking and around $150 in materials (baffles and foil barrier) making the roughly $1.20/square foot cost of this improvement the most expensive per-square-foot change that I'd made. Again, I balked at doing it initially due to the cost, but I thought that I would regret it over the next 15? years until we got our next new roof if I didn't do it. The improved airflow and ventilation coverage seemed worth it.
The benefits from this job are already pretty well accounted for in the analysis of the 2009 energy data here since this change occurred in July of 2009. I am considering trying to examine 2009 May and June, before the change, with July-September, after the change, but that might not prove very conclusive given the short timescales.

In the meantime, the number 2.6 has been on my mind, and its significance might require some more discussion. Until next time!

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