ate a continual air/moisture barrier around the
entire house. The total r-value for the walls on
the original part of the house is R- 36. In the
addition it is R- 48.
The basement walls, which are 8-inch-wide
cinder blocks, needed to be insulated in a way
that didn’t consume too much interior space. We
opted for a wall of 2x3 studs held 2 inches off the
block walls. Then we sprayed behind and between
these studs with 4 inches of bio-based, closed-cell
foam. This resulted in an R- 27 basement wall, with
a loss of only 4-½ inches of space.
On the original basement floor, in order
to avoid losing too much ceiling height, we
put down only 1-½ inches of rigid foam board
(R- 7. 5) and covered the floor with plywood. The
addition floor has 3 inches of foam board (R- 15)
under the slab.
Copyright © 2012 by the American Solar Energy Society Inc. All rights reserved.
tom of the originals, using plywood “ties” to hold
them together end to end. These 11-inch bays, and
the 2x4 walls, were filled with dense-packed cellulose. To add to the roof insulation, after stripping
off the old asphalt shingles, we screwed down one
layer of 3-inch-thick polyiso rigid foam boards.
Staggering the joints, we added another 1-inch
layer of polyiso and taped all joints.
The challenge was insulating the original
exterior walls, which were now stripped down
to the 5/8-inch plywood sheathing. My choices
were to apply two layers of rigid foam, like we
applied to the roof, or to spray foam the entire
exterior. My building consultant, dave raponi,
suggested the latter for a better air seal and
possibly less cost. one of the carpenters, Tom
Cuccaro, came up with a way to frame over the
sheathing and around the window/door openings so that spray foam could be applied.
Tom designed a type of secondary framing system, consisting of 2x3s attached to the
exterior of the original sheathing. These nailing strips, spaced 16 inches apart, are held 3
inches off the sheathing with sections of 1-inch
PVC pipe, thus creating a continual plane of
space for the foam to be applied into. long
screws were drilled thru the 2x3s, the pipe
and plywood and into the original 2x4 studs.
This also created a new framework around the
house onto which our siding and trim could be
nailed. Once all the framing was finished, 3 to 4
inches of closed-cell, bio-based spray foam was
applied, filling all spaces behind and between
the framework and creating an airtight layer
of insulating foam. About 1 inch of air space
was left between the foam and the outer edge
of the nailing strips, creating a drainage plane.
Even the addition, constructed of Durisol ICFs,
was sprayed with 1-½ inches of foam to cre-
Achieving near-zero energy
originally I thought we’d be able to move
into the house in four months. We started the
demolition in August 2009, and moved into the
partially completed house May 15, 2010 — nine
months later. The solar panels were online in
august, one year from our start.
It was a mad dash, but with a lot of team
effort, great attention to detail and quality workmanship by all, we came close to our goal: a zero-net-energy, super-insulated, deep energy retrofit,
using the “5-10-20-40-60 rule” as a guideline
for insulation levels. New York State Energy
research and development authority and our
home energy rater/consultant gave the house an
Energy Star rating of 5 stars plus, the highest tier.
The blower door test revealed an excellent level of
airtightness: 1.39 air changes per hour at 50 pascals. In order to keep our electricity usage down,
we chose all Energy Star-rated appliances. The
In the existing part of the house, the rafters were
2x6s and the walls were 2x4s. To get a lot of
insulation in this existing framework, we chose
dense-packed cellulose insulation in between
the rafters and in wall cavities, 4 inches of polyiso rigid foam on the roof and closed-cell spray
foam covering the exterior walls. Each rafter was
beefed up to 2x12 by adding a 2x6.
lighting is 55 percent CFL, 14 percent LED and
31 percent traditional incandescent. We could
save even more by getting rid of all incandescent
lighting and using our clothes dryer less often.
The project cost went above our projection.
However, we added many features and design
elements, going beyond the planned deep energy
retrofit to a total renovation. The estimated cost
of the deep energy retrofit portion of the renovation, including all new electrical systems, plumbing, windows, doors, mechanicals, photovoltaics,
insulation, roofing, siding, the durisol addition
and so on, is about $150,000. The result is a comfortable 2,200-square-foot, beautifully designed,
all electric zero-net-energy home with three
bedrooms, two bathrooms and two kitchens. In
one year of producing electricity, from august
2010 to August 2011, we purchased about 4,100
kilowatt-hours from our electric utility at a cost
of about $530 (plus $370 for taxes and delivery
charges). That covered everything, from heating
and cooling to hot water, cooking and laundry.
achieving near net-zero-energy was arduous,
but satisfying and well worth the effort. anyone
committed to transforming an older house can
do it, too. It takes a lot of research, hard work and
the right team of people. With the abundance of
poorly insulated, in-need-of-repair homes in this
country, opportunities abound to renew, recycle
and retrofit. ST
Robert Ritacco has been the owner of r.J. ritacco
Painting Co. since 1980, and of ritacco’s retrofits since
2010. He is married and has two daughters. robert
and Wendy live in ulster County, N.y.