recycled steel

EHH week 03: foundation

The lower floor of the new house will be a concrete box, with full height foundation walls on all four sides.  These walls will be exposed, so the concrete subcontractor had to take extra care to layout the form boards and the snap tie spacing.  They did a beautiful job!  Amazingly, the long diagonals are only 1/16” different, meaning it is perfectly square.  The tall downhill wall is flat and plumb, a real work of art.

We are building this house from recycled materials.  The steel rebar is 100% recycled steel.  Under the slab on grade, instead of gravel we are using 100% recycled glass, called “cullet.”  It comes from the local curbside recycling bins that collect glass bottles.  The concrete wall has a brown dimpled drainage mat on the inside, made from 60% recycled HDPE.

The concrete mix contains blast furnace slag, a waste product from smelting iron into steel.  The slag has the added benefit of reducing the Portland cement from a typical 5-1/2 sacks per cubic yard (517 pounds) to only 2-1/2 sacks (235 pounds) without a loss in strength or durability.  Manufacturing 1 ton of Portland cement requires 6 million BTU of energy, so we are reducing our energy consumption before the house is even operational.  


EHH week 31: interior stair

Most of the main rooms are on the upper floor of this house, but a few important rooms are on the lower floor.  The stair between them is intended to allow a visual and audible awareness between the two levels, so that the upstairs and the downstairs would feel connected.


The design of the stair is decidedly modern in keeping with the aesthetic of the house.  The treads have open risers and the railing is a minimal cable style.  The treads are detailed to appear to float with hidden brackets connecting them to the side wall.  The open risers also allow the homeowners to see through the stair so the downstairs hallway does not feel like a dead end.


The metal for the stair is made of 85% recycled content steel, finished with a durable and low toxic polyester powder coating.  The wood treads are salvaged lumber from the military port of Oakland CA from buildings constructed in 1941, finished with a low VOC water based polyurethane.


After the house was framed, we shifted the stair about 1 foot to make more room at its head end.  The passage from the downstairs hall beneath the sloping steel beam felt a bit tight when we mocked it up.  Because the stair passes under a closet, we framed the floor of that closet a little shallower to afford more headroom.  Anticipating this possible change, we had earlier oversized the structural floor opening at the stairwell in case we needed to shift the stair.  I’m glad we planned for that!

EHH week 26: steel railings

The steel decks and bridge have been installed, all but completing the exterior.  We chose steel because it looks better than wood when viewed from below and because it is strong and durable.  For the decking boards that are the walking surface we used tigerwood, a naturally rot resistant tropical wood that has a color and figure suiting its name.


All the steel for this project is 86% recycled steel from the rolling mill.  After cutting, drilling, and welding in the shop to fabricate the specific pieces needed for this house, it is sent for finishing.  We used a polyester powdercoat that is baked on.  The advantages over paint are several:  it is almost impossible to scratch, it never needs to be recoated, and it requires no solvent chemical to apply.


Before any steel is fabricated, each piece is drawn by hand by a detailer, in this case Ty Torjussen.  He is careful and thorough and I really enjoyed working through the nitty gritty issues with him.  Despite our care, it is always a nervous moment when the steel gets delivered and installed.  Will it all fit?  Sure enough, we overlooked one place where it was impossible to install screws into the decking boards.  So Model Remodel had to remove and alter a few pieces of steel to make it work.


The decks allow the homeowners to step outside and the stairs lead down to the garden.  For the first time, it feels like the home is connected to its garden.