Second Roof

Hi all,
Second roof took the best part of the week. The first roof and wall assembly gave us a continuous air seal and insulation cavity without the punctures that rafters produce in the envelope.

Three reasons for putting on a second roof framing and foam:
1- Second roof is added to achieve a higher overall R value,
2- It eliminates the roof's cavities from reaching dew point and condensation within the cavities,
3- It achieves our 2 foot over hangs.

We stayed home Tuesday waiting for a rain that never happened. Next week we begin exterior treatment and hopefully get our composition roof shingles finished.
See you next week.........Terry

The plywood and all the framing members were sprayed down with a 10% solution of boron. Damp and dry wood termites leave their nest colonies and fly off every year to recolonize. They hit a building at all levels in mass looking for holes and cracks to crawl into and start a new family in wood fiber and darkness. First defense for a structure is no holes or cracks in the assembly. Second defense is to soak down all the wood with a boron base application. Boron is not a neurotoxin, like most insecticides, and does not directly affect the nervous systems of termites and wood boring beetles or humans or pets. Boron is an enzyme inhibitor. When termites bore into the wood they are forced to eat the boron as well. Boron messes with all the body functions of the critters including their digestive system and they sadly wither away with a host of problems.


Termites prefer to start their inward journey through end grain so we double soaked the rafter tails with boron before the facia was applied.

Second roof applied over our first air seal roof. Now we have two foot rafter overhangs. This layer does not need to be air sealed. The 2x4 "sleepers" were attached with a nail gun from the underside of the plywood. They are set in between the 2x8 rafters below to minimize the thermal bridging between the two roof assemblies.

3 1/2" polyisocyanurate (rigid foam) set in between 2x4 sleepers.

Sleepers and foam ready for plywood.

Air sealing the exterior shell

Hello again,
Another good week. We finished air sealing the exterior shell, tested it for air leaks, installed the windows and got on half the second roof on and covered it for a pending rain. On Friday and Saturday more than 140 people, CLAM members and building professionals from all over the Bay Area, came out for the "See the Guts" Tour to see how the Passive House is put together from the ground up, focusing on the air sealing of the exterior shell.
See you next week..............Terry

Our first blower door test with no windows cut in revealed our "D" ring was too big and we got fluctuating read outs. For those who do not know what that means: a "D" ring is used in super air tight tests. I called up the manufacturer of the blower door company and they said "Holy ~*^- ! you guys are in "E" ring territory, we don't see that very often."

Here Bill is putting tape over our D ring in an attempt to make it smaller so we might get the LOW flash to stop going off. It worked and we got .11 and .12 CFM readings (not accurate but revealing). Again, for those who do not know what that means: you could not find a hole big enough to let a fly egg pass through.

After the first blower door test we cut out the plywood sidewall in preparation of the windows. We used Serious Windows with an R- value of 7 and equally as important, Serious windows are very air tight. here Jorge, Sebastian and Bill are tilting the window into a wet bed of caulk.

I did a second blower door test after all the windows were installed to see how much they leaked.The new test numbers showed a negligible difference, verifying air tight windows and installation. Note: I blue tape sealed the blower door shroud all around the jamb and tightened a bungee cord around the fan shroud to assure no leakage in the assembly. I also ordered the E ring for the next test.

Ready for next roof. Shell exterior air sealing is done.

Next roof- this time with two foot overhangs.

3 1/2" polyisocyanurate (rigid foam) in between the 2x4 sleepers/ overhangs.

James Bill of ZIA (zero impact architecture)and the Passive House architect for Blue2, explaining the coolness of the Passive House on the "See the Guts" Tour.

Charles of Mr Insulation showing a demonstration/sample wall section of insulation at the tour. We screwed up two sheets of ply, drilled three 1 1/2" holes and Charles blew in dense pack cellulose behind the plywood. We then pulled the ply off to reveal these packed cavities. We will be using cellulose for all the interior insulation.

Framing

Hello all,
Framing is a beautiful thing to look at. It is orderly, soft and when open to the sky it has wispy overtones of suppleness with hints of fortitude.
This week was about framing. It is an upbeat activity that ends the week on a good note.
Thank you all...........Terry

Notice no rafter tails sticking out. This eliminates punctures in the air seal and insulation of the roof and wall assembly. Confusing? Imagine a two by four going through your bedroom wall and resting on a planter box outside. It would be hard to seal around it so it did not leak air. Imagine the combined air leakage with forty of these punctures in the wall. A roof rafter does just that except it happens up high and is incorporated with the roof so it looks good and we have come to accept- it as normal. We will be adding the rafters later on top of the first roof. Pics to follow.
Also notice the made up foam header at left with metal plate was made out of our form boards as well as the high up end blocking between the rafters. The foam in all the headers was from a project I did a few years ago- sometimes it pays to save stuff. Also notice each roof rafter lands on a wall stud, thus eliminating the need for a double top plate.

Cut, foam and nail.

All the edges and openings of the framing were foamed to receive the sheets of plywood.

A sheet of ply being tilted into foam bed.

We got tired of turkey sandwiches and Snickers so Adriana, Jorge's wife, on left, made us tomales and salad with fresh mangoes. Jorge with family, Toni (videographer) and Bill in center, Sebastian in red and Felix who joined us for the day and myself.

Note-no headers on end/rake wall. If I had built this house a year ago there would have been.

Slab & Start Framing

Hi again,
Between rain and County inspection it was a three day work week. We formed the steel on Monday, stopped work for inspection on Tuesday, poured on Wednesday and began framing on Thursday. Got in a few hours on Friday before big rain.
Enjoy.........Terry

House slab rebar in foreground, entry slab behind.

Foam sealing around waste line punctures through 13" foam bed.

Concrete will fill up to top of verticle 2" foam.

First concrete being pumped from truck into same corner as above pic.

Half way- guys with rubber boots walk in 6" wet concrete to smooth out concrete.
After slab is finished, wood mudsills are set on top of a bed of roofing tar- this is the first step in air sealing the framing to the concrete slab.

Thursday morning. Earlier in the week, I had decided to not start framing until next Monday. I was hoping to get more information about the OVE framing from Katy, the engineer. I was hoping it would rain so we would not have to start. I was looking for any reason not to start. Truth is I was scared to start. All my training, classes, preparing, endless emails and meetings were over and now I had to actually begin to build the first new passive house in California. The burden was enormous and I was nervous and intimidated. I just needed a little more time.

Over tea and toast, I found my folly. I reviewed some PDFs on OVE and decided to cast my fear aside and just go for it. I dressed as if I were a soldier going off to battle. By the time I arrived at the job I was jubilant and cheering on the guys. “We are going to build a house today!”

Tilting up the first 2x6 wall section. The finished concrete slab is covered up with tarp and plywood scraps from another job. That green painting on tool shed/ office was a gift from Wild Carrots to 'Artisitify' the site.

This is a header for the living room wall window. It is composed of 2 1/2" of foam sandwiched between two 2x6s. It breaks tradition from "old school" headers in that it offers a thermal break in the wall assembly. A traditional 6"x6" solid wood header would have an R- value of approx R- 5.5 whereas this header has an R value of approx R-18. Our current building slogan is "less wood, more insulation".

South wall almost complete. Rain on finished concrete slab.

Happy Easter.......Terry

Week of March 22: Foundation Insulation

Hello again,
This week was a series of stops and starts. All is good, spirits are high and we are all happy to come to work every day. Yay for CLAM...........Terry

Drains for roof downspouts. They run around foundation and down hill to the far south end of the property near the school where they terminate in a rock drain trench. Under this drain is the drain for the ground water which connects to the same.

We used the dirt we dug out of the footprint to backfill around the foundation.

This foam board is designed to stand up to the heavy loads concrete slabs deliver. Pricey stuff but this insulation will be silently saving energy and reducing carbon production for perhaps a hundred years or more.

Setting ABS waste lines that run through rock bed under the concrete slab.
Here Joel Langdon is glueing up waste line for kitchen sink. There are two lines in the foreground. The fatter one on right is the toilet waste; the other is a gray water line that will pick up the tub/shower and bath sink. For now they will join together outside the foundation and empty into to septic. This makes the house "gray water ready" which means that later when the County comes out with a comprehensive gray water plan, we will be able to separate all the household water for landscaping, leaving only the toilet water to continue into the septic.
The living space wall that separates the bedroom from the living room will stand above the concrete wall that is crossing the rock pit. The brown piece of wood is approx where the hallway continues into the bedroom and bath.

Sebastian tamping down the surface of the leveled rock pit.

First layer of foam board laid over plastic which is laid over the rock. White pipe sticking up is receiver for roof gutter downspout.

Second layer of 3" foam board on top of 4".The top layer of foam was set on top a wet bed of foam along every seam of foam underneath.

Top sheets of foam were wet sealed with a foam gun along every blue foam seam and along the concrete wall connection.

Plastic then covers the completed double foam layer giving us a 7" foam bed upon which the concrete slab, which is also the finished floor, will rest.

End of day-rebar/steel, laid out on top of plastic for Monday's work.

March 19
We poured the perimeter footing and stem wall yesterday and began stripping the forms today. It never ceases to amaze me- you spend a week making the mold, suspend steel bars in it, fill it with a liquid, next day pull off the mold and you have a monolithic cultured stone box onto which a house will stand for a century or more.
Too much fun........terry
Editor's note: Narrator is Terry Nordbye, West Marin contractor for over 30 years, who is newly fired up about reducing our carbon footprint in buildings with passive house renovation and construction.
Tuesday, March 16th- begin outside of forms

Friday, March 19th- foundation poured, forms partially taken off.

The house surrounded by the outside boards of the foundation boards with a ready pile of steel. The boards on the saw horses used for the forms will later be used for the roof rafters. The rest of the form boards we used were from the foundation of the Blue House.

Typically one uses Portland cement as the hardening agent in mixed concrete. Portland cement, derived mostly from heating limestone in a kiln is mined all over the U.S., Canada and Mexico. We used a 30% fly ash content to replace Portland cement in our cement mixture. The fly ash is a waste product from coal generated electricity plants. Turns out our fly ash comes from a coal fired generation plant in South Dakota, it is then trained down to a distribution plant in the bay area where it is then trucked to point reyes. Is fly ash more green than Portland cement? Depends on where the Portland cement was mined and manufactured and how it was delivered. Keep in mind the fly ash is waste where the Portland cement has to be made.

North east corner of foundation after forms are stripped off. Concrete will be back filled to just above line in concrete- 8" above finished grade. Bolts sticking up will attach to key wood members to anchor the house framing onto the concrete footing. Rock pile will be graded out flat as a bed for the next step- foam insulation for the slab.

Setting up for the Foundation

Here's Blue2 laid out for the foundation. From this vantage point it looks bigger than the Blue House, but it's a 750 square-ft. second unit. The recycled wood stakes in use here were trim from the cabin that used to stand here. The stakes outline the face of the new concrete foundation.


We used the old form boards from the Blue House to form the Blue2 and again here is some of the old house trim used for form stakes.


Most of the inside form boards are set. John Hope in CAT piling up the extracted dirt around outside perimeter of foundation. Later this dirt will be graded back against the new raised foundation wall. The 30 ft building site dropped off 20" from the planned front door on right to the bottom corner of the wood forms on left. The top of the form boards will be the height of the finished floor. Jorge is standing in what will be the bathroom.