This is the ongoing saga of our experiences building a beautiful Modern Chateau in Atherton.  Live the process vicariously with us as we do this together in real-time…

Part 3: Up From the Bowels of the Earth!

January 18, 2021

It was August of 2020.  We had bought a well-situated lot a year earlier.  We had designed a beautiful house on paper during that time.  Now it was time to get building. 

But how do you actually start building a house?

In this riveting (see what we did there) installment of our Construction Blog, we dig deep and make a subterranean setting for sublime satisfaction: the foundation.

Step One to build a foundation is to remove the old house, remove the unwanted trees, and scrape the lot clean.  Ah.  A blank slate.

Step Two is to hunt for gold.  You dig and dig, and no one every really finds any, but the next project could be the one where you get lucky.  You never really get upside surprises with schedule and budget in this business, but some enterprising pirate might have made it to our lot and hid a stash. Sadly, again we found nothing.

The amount of earth excavated is actually way more than the size of the basement, as workers need space outside the future edge of the house to work, and you generally have 45 degree slopes from the surface nearly down to the lowest level, to prevent collapses (though it gives us a fun inverted Mayan temple complex vibe as well).  So while creating our beautiful pit, we also create a small ski hill in the future back yard.

Before we go on, we need to talk about water.  While excellent for your health, it can really trash your home.  Controlling water is crucial.  Water in the wrong place does way more damage than fire—rot, fungus, pests, mold, decaying wood, cracked foundations... none of it good.  Yikes!  But we all love sinks and fancy toilets and oversized showers and powerful dishwashers and big pools and thirsty mature trees.  So getting it where it should go, and keeping it away from where it shouldn’t, is a huge deal. Subterranean plumbing that goes below or inside the foundation, and dissipation areas outside the foundation where rain will end up (all the way from the future roof!) is pretty much the first thing that gets built.

Foundations have a more-or-less flat bottom, called a mat slab.  There are actually quite a few creative cutouts for elevators and ejector pumps and lightwells and tiered seating in a home theatre.  But underlying all of that is a thick kinda-plastic kinda-resin layer of sticky sheeting called waterproofing.  And below that is special gravel (drain rock).  The whole idea is to keep water away from the actual concrete. 

Concrete is a pretty useful substance.  It has incredible compressive strength—you can stack a lot on top of it—and it is very durable.  But twist it or push on it too hard in the middle of an unsupported section, and its snaps like a cracker.  This is why we use tons of reinforcing metal bars (“rebar”).  I mean, literally tons.  So much metal gets cut, bent, placed, and painstakingly tied together.  A modern basement around our area might be 5-10% metal by volume to withstand a whatever comes at it.

When wet, concrete has a consistency something like thick pancake batter.  Which is fine if you want to build a pancake-looking house, but how do you get it to end up in nice smooth rectangular shapes?  We build wooden structures (“forms”) that look somewhat like the eventual wooden walls, but are temporary holding pens for all that delicious slurry to cure into a nice flat wall.  Then the forms are all ripped off afterwards.  It’s quite a lot of work!

Finally, the big day arrived.  On November 23rd, 23 dump-trucks delivered freshly mixed concrete into the bottom of our lovely pit.  Getting it to the right place involves arcing it overhead hundreds of feet, then spewing it out (like some sci-fi movie alien queen disgorging her endless egg sacs) by guys splashing it all around the rebar so that no air cavities remain.  It actually comes out hot!  A few days later, it is flat and hard enough to walk on.

Do you know the phrase “this is not set in concrete”?  Well, our stuff *is* set in concrete, and is not metaphorical at all!  If we want to change something that is set in the concrete now, then we are inviting a lot of monetary and temporal pain.  If some sewage pipe is off by a few inches, that means some toilet has to move, then some wall has to move, and then the beauty and symmetry and perfection we designed for might be marred.  So an aggressively clear vision at the outset has to be married with flawless execution.  It might seem like a mundane length of PVC tubing at the bottom of a pit, but we’ve thought about sightlines to the pool house, and the enfilade sensation in that corridor, and how the pendant lights relate to the vanity to make the owner feel successful when looking in the powder mirror at just the right angle, so that humble PVC tube *better* be in the exact right place.  The care we put in at this stage translates to zen harmony for the future owner.

Next, we do it all again for the sidewalls.  Rebar ties in to what was bent up from the slab.  It climbs the sides like a gray bamboo forest.  Forms are built on both sides of the metal to hold in a phenomenal amount of concrete that would really enjoy just spreading down and out for a good rest.  More dump trucks pay a cordial visit, concrete dries, the forms are stripped away, and voila!  We have basement walls!

Our impregnable walls do have a soft spot however. Penetrations are needed for a handful of utility connections in our lovely walls, so we pre-set plastic sleeves into the forms. When the concrete sets around them, we have a small planned opening in our armor, through which a pipe or two will travel. In a year’s time, fresh water will be flowing in, or fresh sewage will be flowing out, through these spots, like an umbilical cord connecting Mama Atherton to Baby Shearer.  But for the next year it’ll just be capped off and buried.

Waterproofing gets pasted up the sides.  Earth gets replaced back around the house (the moat is an architectural feature than we’ve not been bold enough to design in to any of our builds). Every “lift” (~6 inches of dirt dumped down) of earth gets pounded into place with a part-tool, part-vehicle thing that looks like the love child of a meat tenderizer and a jackhammer. Or like one of the other droids on the Jawa Sandcrawler that R2D2 knew to avoid.  This pounding ensures that the ground is as solid as we expect in the future.  If you just dump earth into an area and call it a day, it will subside over time with seasonal expansion, contraction, and rain.  And no one likes that.

So, by January 2021, what do we have? 

We now proud owners of a super-heavy boat, which is very unmaneuverable and quite blocky.  But water cannot get in, and the earth is sculpted as we intended.  Groundwater can slosh around it, but the future residents will stay dry.  And despite being in a basement, the ample lightwells and sunken patios will let light spill in from above.  We’ve dealt with a lot of mud thus far, but it will become ethereal and heavenly soon.

Thus far, our project has been 95% concrete, 4.99% metal, and 0.01% plastic.  The next frontier, which will let us have rooms and floors are roofs… is wood. Lots and lots of wood.

Now, to start building up!  Tune in next time for framing!

Up Next: Part 4: Framing for Victory!