NOTE: This is a first for Sustainably, a story written by someone other than Michael. Please welcome Jeremy Marin of Arlington, a very committed advocate for energy efficiency who puts a great deal of effort behind his beliefs, as this story attests.

By Jeremy Marin

On March 7, about 60 [update: it was more like 45] people converged on two homes in Cambridge for what HEET (Home Energy Efficiency Team, www.audreyschulman.com/HEET/index.htm) terms a “barn-raising” as part of Brain Shift’s (www.brainfound.org/) Energy Smackdown competition (www.energysmackdown.com/) involving teams from Arlington, Medford, and Cambridge.

Modeled on the Yankee tradition of communities working together to help a neighbor, the group went to work sealing the homes’ building envelopes to reduce their energy bills. Participants were divided into teams: attic, basement, interior caulking (baseboards, windows, etc.) and water conservation (low-flow shower heads, aerators, etc.).

The homes, in desperate need of money-saving efficiency work and owned by low-income families who needed help, were found by Homeowner’s Rehab (www.homeownersrehab.org/home.php).

Most of the materials were provided by The Home Depot (www.homedepot.com/) and a thermal scan was done by Byggmeister Inc. (byggmeister.com/) before the barnraising occurred. The scan included photos so those of us leading the project knew where to focus our efforts and what materials would be necessary.

Before we got to work, Alex Steinberg from JBS Home Inspections (jbsinspections.com/) and I looked at the work necessary in the attic and realized that in addition to air-sealing, there was one area where we could pull the floorboards and put down insulation. We quickly grabbed one of the homeowners and encouraged him to purchase formaldehyde-free insulation made by Johns Manville (www.jm.com/insulation/building_insulation/4465.htm) that we could put down.

That done, our team of six or so went to work: First we put mineral wool (also called rock wool), an approved fire stop material, in each of the bays on the sides of the house. We covered that with expanding foam to prevent cold attic air from going into the house as well as warm interior air from flowing into the attic.

There was a large hole where the vent stack came through the attic floor. We cut tin to fit around the pipe to act as a fire stop, screwed it into the floor, and foamed around that.

The bathroom fan had two major problems. A large hole where exhaust exits the side of the house was allowing cold air to billow in. We stuffed a small amount of insulation into the hole and then foamed around that. The insulation went in first so the foam didn’t overflow and rain down on the outside of the house.

After making certain the fan was IC-rated (insulation contact) and safe to have insulation right up against it, we used aluminum tape to seal all the holes in the housing that sits in the attic – we didn’t want the foam expanding into those holes and raining into the bathroom. We then used a small amount of insulation to fill the holes around the outside of the housing and foamed over that to make it a tight seal – no more air flow.

Expanding foam went around the attic windows, which were recently installed, to ensure a tight fit with no leaks.

The homeowner came back from the store just in time – we took a 10-minute break before tearing up the floorboards and putting the insulation down. Once we were done, we settled down to a meal courtesy of Whole Foods (www.wholefoodsmarket.com/).

Even though I’ve done lots of sealing and insulation work, I still learned some lessons:

— Several of us were excited to try out the 20 lb. can of expanding foam provided to us. We’d all used “Great Stuff” and similar products, before but never a big can like this. Unfortunately, we suffered what turns out to be a typical problem with these cans. The nozzle, previously used, was completely blocked. Lesson learned: Unless you know the nozzle is going to work, don’t rely on it. We ended up doing all the sealing work with regular-sized cans of foam instead.

— In the floor of the attic, you could see through several voids into the house below – there was no plaster showing through the lath. Thi

s signals an interior wall below and another route for warm air to come up and cold air to go down. We could have cut tin to fit those areas but several areas were very small and this was a time-limited event, so we used a small amount of insulation to fill those voids, stuffing it between the lath, and foamed over them to create an air-tight seal.

— Everybody in the attic wore masks, including me, to keep us safe and healthy. What I hadn’t considered was that my personal mask, a respirator type, made it difficult for people to hear my instructions. For the crew to hear me, I often took the mask off, and by the end of the day, the dust and my allergies had left me with laryngitis. Lesson learned: Safety equipment is only helpful if it is used.

A few items remained at the end of the day, but they required using foam on and around the very narrow staircase to the attic. If we’d done that work, everybody going up and down the stairs would have had foam all over their bodies and shoes, tracking it through the house. Instead of risking that, we gave the homeowners a detailed list of remaining items to do and how to do them.

It was a great day. Lots of fun, lots of great people, and a fantastic amount of work done by an all-volunteer crew. I’m looking forward to helping more people like this in the future.

CAVEAT: While the work outlined above applies to most homes, there are technical and safety issues. Before doing any similar work, you should fully educate yourself and/or consult an expert.