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.

Welcome to CLAM's Blue House Blog!

On February 20, we broke ground on "Blue2", the 750-foot second unit being built behind the "Blue House". Blue2 is designed to be the first new construction certified "Passive House" in California as well as the first in the state built for affordable housing. This blog will chronicle the construction of Blue2.