Wednesday, September 29, 2010

Construction status (foundations, basement, garage)



The root cellar/basement walls are complete, the garage concrete and framing is complete, and most of the two story section of the house has footings poured. Structural steel/welding is happening as I type. There’s been lot of head scratching going on thinking about how and where to route plumbing (water, gas, waste, storm water collection, vents, hydronics) and electrical wiring (power, sensors, telecom) prior to pouring structural slabs and beginning ICF wall construction. Even with all of the careful planning, I don’t have any expectation that we won’t have some surprises to deal with later.

There’s nothing terribly interesting about the garage. It is detached and no need for stellar thermal and energy performance, so it is framed and sheathed in the conventional way. Adding “Thermafiber” (foil backed OSB) to the garage roof was a simple and cost effective way to reduce heat gain. Foil addresses heat radiated through the roof, one of the three ways heat is transferred. Very simply put, the other ways are conduction (through a solid) and convention (through a fluid/gas). This is why typical fiberglass insulation caries a foil layer on the back of the paper (fiber side), to reduce both conducted and radiated heat gain. Foil has a low emissivity coefficient and radiated heat transfers directly proportional to the emissivity of the material.



Kitty hired a male model to wire the garage ;-)



On belay! (Nacho and Rourke)

root cellar and garage




















The root cellar walls are complete including water proofing; a system from Tremco that includes a polyurethane sealant (caulk), Tremproof “black snot” barrier, MiraDRAIN barrier protection sheet, and filter cloth. First the CMU joints were caulked, brushed over again with black snot and then the entire wall surface got two coats of black snot. On the outside walls where storm water and irrigation water can seep though the soil, there is a protective barrier sheet over the black snot and two feet of drain rock outside of that. It seems unlikely that water will ever touch the barriers and will just drain down through the rock and into the drain pipe. On the interior walls (situated under the house) where there is close to zero surface water, there is MiraDRAIN over the black snot and then a filter fabric over that and dirt fill. At the bottom of the root cellar walls, drain pipe gravity drains to the street. That all sounds very simple, but getting the finished floor grades and header clearances right took a bit of detailed planning and execution!




"Black Snot"


Looking ahead, one of the issues to consider with Durisol is that is that the cells are closed and therefore need to be threaded over the steel rebar. However high the rebar is, that is how high the block must be lifted and lowered into place. Therefore, vertical rebar lap length is an important consideration with regard to labor. The building code has a safety factor; the structural engineers generally apply more safety; then, the contractor applies even more as a practical matter for inspections. Either minimize lap lengths without compromising structural integrity, or plan for the extra labor to stack blocks. I plan to write later about my thoughts on sustainable building (resource optimization) in the economic and regulatory environment and architect/engineer/legal culture I am building in. This issue is a form of waste that needs to be addressed in that context.

The time lapse camera got adjusted by (I suspect) some squirrels, so it is down and I am looking for a new place to mount it.


3 comments:

Unknown said...

Pretty cool, Jon!
-Jana

Unknown said...

Thanks for sharing such great information!
-Elizabeth

Unknown said...

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Central London Basements