A bit of foam

Ideally this would be the order of events, now that the framing is done:

1. Install the windows.
2. Apply the rigid foam insulation to the walls.
3. Apply the water shield membrane to the roof, running past the edge of the sheathing all the way to the outside of the foam on the walls.  Hopefully water will never get to that membrane, but if it does, you want the water to flow to the outside of the foam.
4. Apply the rigid foam to the roof.
5. Apply another layer of plywood above the roof foam for nailing the shingles.
6. Shingle the roof
7. Build the porches.

But the windows aren't here and aren't due to arrive until October 2nd.  So by installing a bit of foam just in the back corner, the builders were able to get started on the back porch.

It's a bit tough to see in the picture above but there are two layers of 2" foam on that corner.  The outer layer ends about 18" below in the inner panel to keep the joints staggered.

The aluminum channel the builders fabricated
to protect the bottom of the foam from insects.

In order to start applying the water shield membrane,they've applied a bit of the foam board to
the area under what will be the eaves.

The water shield membrane covering the roof and running
out over the wall foam.

Plumbing

Plumbing sure has changed in the past 20 years.   PVC drain pipe long ago replaced cast iron, but it's relatively recent that PEX supply lines have replaced copper.

The manifold is like a circuit breaker panel for plumbing.  The red
wrench stuck to the front of the manifold can be used
to turn off the various lines all from this one box.

One question I had about PEX is whether it makes sense to insulate the hot water lines. I'm assuming that hot water in PEX tubing, compared to copper, will lose far less heat as it travels to the tap but insulating still seems like a fairly simple and low cost thing to do. The plumber said no one had ever asked for it before but that he'd be willing to do it. Nevertheless something got lost in the communication with his crew and the pipes are uninsulated. But I'll take advantage of this to do an experiment. Once I'm in the house, I'll measure the temperature at the tap before and after insulating the pipes and see for myself how much of a difference it makes.

PEX and drain/vent pipes in the first floor bathroom.

I decided to replace the only section of cast iron pipe that remained: a section that went through the wall out to the new septic system where it tied back into PVC.

 

While we're talking plumbing, apparently toilet technology has also improved over the past couple of decades and water-saving toilets actually work. I'll be getting this dual-flush toilet from American Standard. The big flush is 1.6 gallons and the small flush is just 1.0 gallon.

Since I'll be living on a lake I'm trying to be sensitive about how much nitrogen and phosphorus I add to the lake. I plan on getting my septic tank pumped more often than strictly required for the health of the septic system. But for that to make a difference I need to minimize how much water I push through the entire system.

Hot water heater

Rick working on the drain/vent lines

The rough plumbing has started. After months of obsessing research, I actually have to decide now about showers, shower heads, faucets, etc.

I'll spare you.

But the hot water heater heater is more relevant. In a tight, super-insulated house, a large fraction of the total energy usage goes toward hot water, so deciding how you want to heat your water is an important consideration. The choices boil down to: electric vs. natural gas and tankless vs. tank-type.  Oh, and possibly solar hot water as well. Greenbuildingadvisor.com has a great rundown on all the options for water heating.

Tankless at first seems very appealing. They're small; they have the promise of never running out of hot water and they don't have any energy losses while not in use.  The disadvantages: they're expensive to install, they're complicated and if they break, more expensive to repair or replace, they add a bit of extra time before hot water appears at the faucet, and they have to be sized for the worst case hot water draw.

Based on all that, I've decided to go with a tank-type.

So gas or electric? Given that I have a natural gas line running to the house, there's a strong argument that I should go with gas.  From a carbon footprint point-of-view, it's better to use gas, since a gas-fired power plant will use about 3 times as much gas to generate the electricity to heat a given amount of water as a gas hot water heater would use to heat the water directly. It's actually more complicated than that since some electricity is generated by solar/wind/hydro (better) and some by coal (worse).

But there's a new generation of electric hot water heaters that doesn't heat the water directly but instead uses a heat-pump.  These electric hot water heaters are about 2.5 times more efficient than the old style.  So 3 divided by 2.5 is 1.2.  In other words, an electric heat-pump hot water heater will burn about 20% more natural gas (at the power plant) than would be needed to heat the water directly by burning gas (in a gas hot water heater).

You can probably already see where this is going - I chose an electric heat-pump hot water heater for several reasons.

• When you have solar panels on your roof, the monthly savings are greater if you use the electricity they generate rather than pumping that electricity back into the grid.
• The cheaper installation costs.
• I won't need to have a vent running through the roof to vent the combustion products of a gas unit.
• This would have been the only natural gas appliance in the house and I like the idea of one fewer bill and one fewer company to deal with.
• Because I have a full basement and the basement is unconditioned (outside the insulated building envelope) I won't be affected by the somewhat noisy heat-pump.
• When the heat pump is running, it removes humidity from the air.  So I'll get a slightly dryer basement.

The particular model I chose is the GE Geospring.  It's $1000 direct from GE and there's $300 federal rebate, so it'll wind up costing me about $700 plus shipping and tax and getting a 240v outlet installed for it.

So what about solar hot water?  For me, it just adds way too much complexity - a whole additional mechanical system that has to be installed, maintained and repaired.  Plus, with the increasing efficiency of photovoltaic panels, there a growing school of thought that it actually saves money to use the roof space for additional photovoltaic panels rather than solar thermal panels.

Oddities

Sharp-eyed observers may have noticed that the roof of the second floor is asymmetric.  In the spirit of "form follows function", the south facing roof plane is larger than the north facing roof plane in order to fit more solar panels than would have been possible otherwise.  Will it look a bit odd?  Yes.  But hopefully only a bit.

Another thing that you may have noticed is that the house appears to have no eaves.  In the more traditional method of framing a house, the roof rafters would extend beyond the plane of the walls to create the eaves.  But that would create a "thermal bridge" between the interior of the house and the exterior.  A thermal bridge is a path for heat to travel without encountering any insulation.

In this house, once the windows are installed, the entire house will be wrapped in 4 inches of rigid foam insulation and the eaves will be added after the foam in order to minimize the thermal bridging.  I say minimize rather than eliminate because there are a few penetrations that seem impossible to design away (I'm looking at you, plumbing vent stacks.)

Ultimately it should all wind up looking like this:

Front elevation by Steve Baczek

Because there will be so much insulation on the outside of the walls, there's less need for insulation in the stud cavities.  I will still be getting dense-pack cellulose blown into the stud bays but having so much insulation on the outside allowed me to specify 2x4 walls rather than 2x6.  This will give me around R-22 on the outside and about R-12 on the inside, as well as about 30 additional square feet of interior space.

At some point, I'll write a more detailed post about the wall and roof assemblies.

Interior framing

Finishing up the exterior sheathing and the interior framing.

View out from the second floor bedroom

The roof on the study nears completion

The half bath and built-in aquarium wall

Sheathed but not fully taped

Window update

Tomas from Yaro Windows called today and said that the windows should arrive on October 2.  The exterior insulation, siding and roofing can't begin until the windows are installed because the windows are going to be installed in the plane of the wall framing and have to be sealed to the exterior sheathing before the rigid foam insulation is attached.

Wall detail by Steve Baczek

When a house is wrapped in exterior insulation, windows set in the plane of the wall framing are called "innies".  You can read more about about innies versus outies at greenbuildingadvisor.com.

Hopefully, between the interior framing, the deck, and the screen porch there's enough to keep the crew busy until the windows show up.

Speaking of windows, I've decided to move the kitchen window from the spot on the south wall right behind the counter to the upper part of that wall.   I gain a nice, high, almost skylight-like window, additional wall space behind the counter and a lot of privacy from the street.

Designing the half bath

There's going to be a small half bathroom on the first floor that will also provide access to the back of a built-in aquarium.   As I had a pretty specific notion of how I want it to be framed, I decided to bite the bullet and see if I could model it in Sketchup.  Luckily I stumbled upon a nice tutorial about using Sketchup to create a framing model.  Several hours later and I had the model shown below.

Not only did Sketchup help me to create drawings that I can now share with the builders, it also helped me to really refine the design of the room.  Pretty powerful stuff and even more so when you consider that the basic version is free.  Sketchup does have a fairly steep learning curve but it's worth the effort.  Now I wish I had learned to use it months ago to model the entire house.

Large open areas above and below the tank to provide
access to the filtration, lighting system and the tank itself.

The door to the half bath will be a pocket door so
the rough opening is double width.

How cool is that?!  Sketchup calls this style "brushstrokes on canvas"
Be sure to click it to see it full size.

Roof sheathing starts

Hurricane ties holding attaching the rafters to the walls

Rafter hangers on the other side of the main roof

Roof sheathing begins

Abi practicing a ballet move

The view through the wall of the second floor bedroom

The end of the main ridge beam.  Hmmm... might be cool if we
finish that wall so that it stays visible!

View from the second floor.

The house from the dock

Main section sheathed, tape and somewhat protected from the rain.

Ridge beam and rafters

You can see the newly installed ridge beam at the top of the photo.

The rafters cut and ready to install

Nailing up the first rafter

A few hours later and most of the rafters are up

Looking toward the kitchen area