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.
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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 results though.

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 (yuck!).
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 can provide.
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 wife.

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 sits.

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 laminate flooring.
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 construction.

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 the EPS.

Finally 1x3 strapping is brought on to the EPS and the framing making one straight plane to put the 5/8" sheetrock onto.

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 shelf.
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.