Thursday, September 30, 2010

Day four....and still digging....

The electric spades were cutting through the bedrock all day - most of the footings are now trenched out. The rebar and rebar cages (stirrups) that form the grade beams arrived today.  Before they can be placed inside the trenches the soils engineer and the city inspector need to agree that the trenches are adequate.

Bea can take us back inside (just really quick because now it's getting dangerous.)

this is the deepest point, maybe two Beas deep...and look who's here - Harper...

The site is getting very crowded with all the spoils (dirt removed for the footings), roots and demolished bits of house.  Early next week they will start the process of exporting the dirt - it looks like a lot on our tiny site but it is actually way below any of the city's thresholds for requiring a special grading permit.  There is maybe 100 cubic yards or less of dirt - for the project I spent the last few years working on there were more than 2000 cubic yards of soil to export.  We were required to have a licensed civil engineer make the calculation ahead of time to submit to the city - then the contractor was required to propose a traffic plan and demonstrate an export route that would not cause hazards.  Whereas on our house the crew will erect a ramp out of a big wood beam supported by posts from below and throw it off the edge of our garage roof to a truck parked on the street below.

view from the back of the site

Structural plan of footings 
view from above

Architectural drawings showing section cuts through the existing house and the new house...

Wednesday, September 29, 2010

Day three...and more trenching

Last night we had to demolish the gas line to the stove
because it was in the way of the new stair so we're learning how to be survivalists.  We ordered an induction burner to use during construction but until it comes our panini grill is our new stove...

The trenches are getting deeper but from this photo of the overall site it's probably difficult to tell just how deep they are.
So Bea and I will explore them to show scale...

Can you tell how deep this one is?
It's this big!

Bea goes exploring...
...the trenches are so deep Bea needs a bridge to cross them!

The existing footings on the other hand are about one foot deep and sit directly on the ground - but then again the house turns 100 in 2 years and it's still standing! (let's cross our fingers now.)

...and the cast iron sewer that used to be below ground is still working and doesn't have any roots in it - which is pretty incredible considering the roots that we found in the trench...

And here are some of the roots we found ...Bye for today! can get out of there now Bea!

Tuesday, September 28, 2010

day two...shoring is in and now...trenching, trenching, trenching!

digging the trenches - this one will be the deepest
 because it is the furthest down the hill
 Because we live on a slope the building code requires that our footings are bearing directly onto bedrock.  When we first started designing we hired a soils engineer to come out and dig test pits to determine the depth from the top of finish grade to bedrock and the quality of the bedrock.  The structural engineer used this information to calculate how wide the footings needed to be and how much they should be embedded into the bedrock for stability.  They determined that we needed footings that are 3'-6" wide and are embedded 24" into the bedrock which was found to be anywhere from 1' to 4' below the surface.  This means the crew needs to get out the electrical paddle spades because that's a lot of soil.  They'll spend the next few days digging the trenches and hauling the soil away because we're not allowed to re-use it.
the guy on the left is our contractor -
he gets out there and works too whenever
he's on the site

when they installed the beams below the shoring they used this jack to raise
the house a bit so that it will be level again when the new footing gets poured

Monday, September 27, 2010

Day one...demolition and site staking

The back of the house came off today so that they can see exactly how to shore it up when they take out the footings.  Tomorrow the plumber will come to cut all gas and water lines that are in the way.

Stakes are placed several feet outside the building line to guide the construction crew when they start digging the footings.

a scaffold is put up as they demolish the exterior

they found an old tobacco canister under the house - handwritten on it is a name C.F.Lott and a date '22 - '25...

by 2:30 the temperature hit 112 degrees - it was a record breaker!

at the end of the day they attached a 14" deep paralam beam to the back of the house -
tomorrow they will install the cross beams to support it.  This will free up the footings so that
they can demolish them too eventually.