Old houses can be made super energy efficient as well!
Post: October 28th, 2013
Deep Energy Retrofit in Jericho, Vt!
Part 8 - Moving Inside
East wall in the old garage. Note the cinderblock wall at the
bottom and the framed wall above. This is classic for a raised
ranch style of home. In the background you can see the new
200 amp electrical box I had installed.
Eco Houses of Vermont, LLC
Copyright 2013 Eco Houses of Vermont, LLC
Chris West is a Certified Passive House Consultant
Affiliated with the PHIUS and PHI 2013
The outside of the house is almost done. There are some small things
that need to be finished. I call them small. They are all big things of
course. The front porch has to be put back up. The deck needs to be
finished. The sub-grade insulation needs to be covered with cement
board. All things that need to be done with varying levels of urgency,
and that level of urgency depends on who you ask. I think we need to
get the sub-grade insulation covered to keep the critters from boring into
them and making homes there. More of a problem in the Fall and Winter.
My wife would say finish the deck and the front door.
They are all on the schedule and need to be done and I am doing all of
these myself. I have started with the cement board as you can see in this
picture. Yet now it is time to move inside.
I took a break from working on the house. Actually I just slowed down the work with some breaks in between for
other work. The summer is ending soon though. This morning for the first time we had a frost threat. September
9th and Northwestern Vermont is already seeing frost. The daytime temps are still up near seventy but the
nighttime temps are pushing 34F!
What have I been doing on the house for the past few months. There are three focuses:
- The downstairs walls need to be insulated to the designed level.
- The air to air heat pump needed to be installed.
- The rest of the HRV needs to be installed.
As is often the case with work on an existing house and even with houses that are being newly built, many of the
steps need to happen before other steps can go ahead. That was the case with the air to air heat pump. In order
to move forward with the installation of this super energy efficient heating and cooling system the wall it was
going to hang on/go through needed to be finished and power needed to be run to it. So ok. Wall and power.
That seems simple. Deceptively so.
Just to remind you, the ground floor of a raised ranch has a stem wall, in this case cinder block on a footer. This
goes between one and three feet below grade depending on where you are looking. This wall has six inches of
EPS insulation on the outside and then a layer of Soprema waterproofing for below grade. That gives me about an
R-25. Not quite what I am looking for so I am adding two inches of EPS to the inside of the wall as well.
The framed part of the wall has six inches of Polyisocyanuric (polyiso) on the outside giving me about an R-37. I
am adding seven inches of rockwool to the framing making a wall that has a final R-value of about 66. I am only
doing this on the framing in the basement, upstairs the wall will have to do with an R-48.
To add this amount of rockwool I need to build the wall out by at least three and a half inches (2x4). I have
decided to go further and build the wall out so it is as thick as the insulated cinder block wall after the insulation is
put on the inside. This is about 10". So deeper window bucks, building the wall out and additional 2.5" plus
strapping plus sheetrock (5/8ths).
Picking up where I left off - the inside wall in basement
Here you see the Intello, an intelligent membrane, being held up to show the
double studs which will house the 7" of Roxul rockwool insulation. If you look
closely you can see the right window already has the new buck installed.
The walls were just 2x4 construction, 16 on center. The
top and bottom plates of the framing are on top of the sill
plate (2x6). Before I started to build the studs out to
accept the 7" of rockwool I needed to define where my air
barrier was starting and ending. My intention here is not to
make a contiguous air barrier which goes along the entire
height of the exterior wall. I have already done that on the
outside, but rather to make a secondary air barrier just on
the stud wall in the basement. Why? Mostly because I want
to get some experience working with the Intello and tapes
on interior air barrier. Partly because I don't like the idea
of that rockwool just sitting in the cavity with the
possibility of rockwool dust entering the house.
The construction I have chosen to add a space between the
rockwool and the sheetrock to run electrical and cable lines
and whatever else can fit in the space I have left between.
I designed this space to be 2.5" so a 2x3 will do the job
without having to be cut down.
To start with I defined the air barrier in this construction as going from the top plate to the bottom plate of the
framed wall. To make sure that it was as air tight as possible without ripping bits apart I taped what I could get
access to along the top plate. The bottom plate sits on top of the sill plate. The way I am taping it the bottom
plate is on the outside of the internal air barrier. I am actually taping the Intello to the top of the sill plate
extension. This means that the air can get through under the sill plate and behind the construction so I used a
flexible silicone caulk to fill that hole.
In order to build the framing out I had to build the top plate and the sill plate out. I cut 2x6 to the right depth,
allowing for it to protrude to the point that the 2" of EPS will end.
The sill plate extention that I am using. Once the EPS has been installed on the cinder
block wall (CMU) they will form one plane from floor to ceiling. Exaclty the look I am
going for. If you look closely you can see the bottom of an old copper hydronic
heating pipe. These are being removed as I move through the walls. I am recycling
the copper and getting $ for it.
Before I start adding studs I want to hang my air barrier.
I am doing this at this point because I want the top of the
air barrier to be attached to the top plate before I build
the top plate out. Why? It means less tape. I won't have
to tape the connection between the top plate and the top
plate extension. Instead I taped the membrane to the top
plate and then added the extender. At $0.49/linear foot
for tape that is a savings in the end.
Once the membrane is taped into place I started building
the wall out using a Larson Truss idea. I just took a piece
of 7/16 OSB, cut it into 4" x 6" squares (or something
resembling that) and screwed them in place. This creates
a very solid construction. The original 2x4 is structural,
the extra 2x4 is just a bump out for the insulation. It
doesn't have to hold much but it could hold quite a bit
using this system.
The Intello is attached to the top plate then the stud is brought onto the top plate
extender. You can see the new 2x4 stud under the Intello here. The extra 2.5" you
see between the outside of the Intello and the end of the top plate extender is the
space I am keeping for running electrical wires, cables, etc.
Once the extender studs have been installed we are ready
to build our window bucks. This was easier than I was
expecting thanks to a handy little tool called the Kleg jig.
This tool allows you to make pocket holes that join two
pieces of wood in various configurations. It was a bit of
an expense (approx. $100) but well worth it.
I am building bucks and attaching them to the window
frame. My bucks are quite deep, 7.5". Instead of building
the buck as a finished box and installing them as one
piece, I decided to cut the pieces and install them into the
window one piece at a time. I felt this ensured that the
whole thing would fit. I'm not an expert at building buck
like some of my builder friends. I'm very happy with the
To ensure a good seal with the membrane and the
window you need to remember that any seam, where two
pieces of wood come together, should be taped or glued
or caulked. I taped.
The buck was installed on top of the factory extension
buck of 2" (for a 2x6 wall). The extension buck is
another 5 3/4" from that factory buck. This brings the
inside edge of the buck to flush with the plaster after all
is said and done. The furby is here because it was exiled
from my daughter's room for making too much noise!
View of the top of the buck with my 'wonderful' Andersen Super Low E windows
This now has to be repeated for all of the walls in the garage,
which are exposed as well as for the parts of the ground floor that
have been finished. When I started to pull the finished parts of the
wall apart I saw the "insulation" job that the previous owner did.
It was well intentioned but ineffectual. There was a layer of foil
backed polyiso on the cinderblock wall and some fiberglass in the
stud walls but the fiberglass wasn't well installed (it is almost
impossible to install that stuff to get the R 3.3 the factory says it
What else is there to do in the basement?
The new floor is going to have two inches (2") of EPS insulation on top of the slab. Although there haven't been any
issues with moisture in the floor or coming up through the floor I decided to ask another expert about what to do
concerning installing a floating EPS floor on a slab that is below grade.
Paul Lyman, owner of the Radon Man, suggested a moisture barrier anyway. He said that in lieu of a plastic barrier I
could use a moisture barrier paint called Drylok. It is a rather easy way to get a good moisture barrier.
The concrete floor and cinder block wall after being painted with two coats of the
Drylok latex concrete moisture barrier. It goes on thick and offers a moisture barrier
with a latex base - low VOC.
Once the floor and the cinder block walls were painted with
two coats (the minimum) it was time to install the 2" of EPS
for the floating floor.
Why a floating floor? I want to create a thermal break
between the slab and the flooring. If I put sleepers down
there would be conduction between the sleepers and the floor
to the slab, cooling the whole assembly off.
To make sure that the floating floor doesn't move around too
much I am going to drill Tapcon concrete screws through the
bottom plates of the walls I am installing to make rooms in
what used to be my two car garage.
When choosing to use EPS you need to make sure you are
using a type of EPS that has the compressive strength you
need. After talking with Joel Baker at Vermont ICF in
Waterbury I decided that Type II EPS would work for me.
Here is a Sketch Up drawing of the garage with
the rooms I want to make. Basically a mud room
by the entrance door, a wall along the main joist
beam and a third wall making an office for my
On the bottom plates of these walls I am going
to use six inch (6") Tapcon concrete screws to
fasten the walls and the sub-flooring to the slab.
This will keep the sub-floor from moving and
thus stop the walls from moving, which could
cause cracking on the walls if this were not done.
The floor is made up of four layers.
1) The slab: upon which the rest of the floor
2) The EPS insulation. Continuous from wall to
wall with no supporting framing between the
slab and the sub-floor.
3) Sub-floor: 23/32" Advantec sub floor.
The orange colored walls are the new walls inside of what was my two car garage. The bottom plates of
these walls will be Tapconed into place so they don't shift. This is a good idea because the floor is
floating - not on sleepers.
4) Laminate flooring with a pad under it (for cushoning between floor and sub-floor).
Ian, from the crew helping on this job, measuring the second course of sub-floor
which will be placed "floating" on top of the EPS. On top of this we will have some
Thermal Bridge Free Detail
If you ignore the wood chips on the floor you can see the slab painted with the
moisture barrier, the EPS and then the sub-floor. This floating floor construction
allows for thermal bridge free floor.
The floor detail is thermal bridge free, with a few exceptions. Those exceptions are the framed walls that were already
installed in the basement. The other detail that I wanted to spend a moment on is the thermal bridge free connection
from floor to cinder block wall.
Since I didn't want to dig out my entire basement slab and put insulation under the slab and then re-pour the slab I
am stuck with the slab to cinder block wall connection. On the other side of the cinder block wall (outside) I have six
inches of EPS. To tie the slab insulation to more insulation I decided to put two inches (2") of insulation on the inside
of the cinder block wall as well. This makes a nice thermal bridge free detail.
The only place where there is any significant possibilty
of a thermal bridge on the inside is where the framing
and the cinder blocks go over to the EPS. It isn't
continuous. However the external EPS and Polyiso are
continuous and creat a thermal bridge free
The drawing to the left acruately depicts the framing
with insulation. The framed wall is not finished. The
framed part gets the Intello air/moisture barrier. On
top of the studs and over the Intello a 2x3 is screwed
in bringing the plane of the framed wall out to that of
Finally 1x3 strapping is brought on to the EPS and the
framing making one straight plane to put the 5/8"
This makes for a nice build out (in my opinon at least)
without the shelf you often get in raised ranch
basements. See the pic below for an example of that
Here is the shelf you often see in raised ranch basements.
It is a handy shelf, as you can see I have filled it with all
sorts of junk. Perfect for books, etc. However I don't like it
and decided to fill the space above the shelf with framing
and insulation instead of some books.
New rooms, new electrical circuits and a heat pump
I know that I said on the main page that I would be talking about the
heat pump and I have done everything except doing that. I apologize.
The next blog post will be about the installation of not only the heat
pump but also of the E-monitor system by Power Wise that was installed.
I got it free of charge as part of an Efficiency Vermont pilot program
called CEED also known as the Cold Climate Heat Pump Program (which
doesn't make CEED it makes CCHPP, but that is another story.
If you like my blog and would like to chat about it or know more about
what this cost and the benefits of deep energy retrofit please get in touch.