Yesterday I tried to track down some Miradrain. My wife and I had been talking to the technical rep at Carlisle, getting a recommendation on their product, and how-to on installing it. We decided to have the guys who did the concrete place it- they’ll do this separately from their work as employees of Orville, a side job. The rightful paranoia that surrounds leakage, seepage, damp basements, etc. notwithstanding, what I heard loudest is the tendency is for this below grade raincoat to fail by gravel puncture during backfill. It makes sense to me to close this loop, despite seldom if ever having to referee finger pointing among subs (thank goodness) in my work, I think it can be an unavoidable bit of human nature. Rather than inviting a separate party to the party I’m feeling better having Luis and Co. plug onward. When they do backfill I’m guessing they’ll be more conscientious of protecting their own work, though to be fair i would’t doubt their extending the same consideration to the work of others.
I ended up going to the concrete supply store down the road where I’d picked up sandbags and clear tarp when we were first starting to excavate (for rain protection/drain mitigation). They didn’t have Carlisle brand stuff, but the W.R. Meadow systems they carry looked pretty similar to me.
Mel-Rol Diagram by W.R. Meadows
Essentially you’re waterproofing the concrete wall and then placing a “drainboard”, a sort of mini egg-crate matrix with a fabric filter on top of that to create a sluiceway for the hydrostatically pressured ground moisture which would otherwise dampen the insides to run down this chase to the perimeter drain (aka “the burrito”). In a way it seems a bit belts and suspenders, with the mastic, the film, and the board but once you wrap your head around it it’s fairly easy to convince yourself it’s money well spent.
$1700 worth of supplies
Mel-Drain already leaning on Mel-Rol.
Bucket of Tar
The Mel-Rol is a 60 mill roll of bituthane with a sticky back. The rep, Gary from WRG, suggested based on the hybrid block on stem wall we “parge” the CMU’s above with a thinned out 1:2 mix of this and water (I guess if the surface was rough/granular they worry about that puncturing the membrane) before we lay up the roll. While Moses (heretofore mistakenly called Cesar by me without correction) was looking at it he remarked “this is what we used to use (instead of the Mel-Rol)”, and I said I’d remembered putting that on in a basement in Nantucket prior to gluing some insulation against it. In that island system the rigid insulation protected the tar coat. Likely because of the sandy soil there, and the flat topography, soil pressure isn’t an issue. The other thing the rep said that differed from field anecdotal knowledge was that applying this roll in vertical strips (as on the diagram) was critical to prevent seam failure due to sagging1.
East Wall with Forms Removed
Here’s the wall and footing exposed. They’ve removed the scaffolding, kickers, everything that existed to board form these impressions. We snapped the red chalkline to superimpose adjacent grade for a guide to limit this waterpoofing. Once installed, then backfilled, we’ll form concrete V-drains at the east and west sides of the house and an interceptor (what I’ve often referred to as a “trench”) drain against the back with a metal grate on it. This visible system for sheet flow off the hill, the invisible one we’re doing now for everything below ground. The soils engineers warn not to mix the two for fear of debris clogging the matrix.
Closeup of Junction Between Block and Poured Concrete
Now seen I can imagine painting this bright white if we don’t cover it all with storage. The nibbly bits can be sanded/chipped/ground off. Another good reason to keep it as bone dry as possible because the paint would surely fail otherwise.
Waterproofing/Parging at North Wall CMU’s
This will receive the bring of the hydrostatic water pressure, so they’ve put the thickest mix there first. Knowing this is the most vulnerable I’ve planned the stair against it, a natural circulation/ventilation/chase beyond the wall.
Ulysses2 and the West Wall Parged
This couldn’t help but remind me of Richard Serra’s wall drawings in its absolute blackness. There’s a show up at SFMoMa we should try and see before it goes.
Richard Serra3 Untitled 1972-1973, paintstick on paper. Museum Catalog (cropped).
NW Corner from Above
The light gray triangle will be above grade and covered in white corrugated steel. The stair from the street follows this slope but is skewed to make it less steep.
SW Corner from Street
The V-drain which comes down this side will end in a catch basin, hopefully tucked enough under the porch and obscured by planting it won’t be too visible. The catch basins at either side will eliminate a wash-out effect at the street, and I think it’s here (at the low points of the site drainage) where it would be great to install gray water capture in the future.
Our Garage with Luis’ Truck Parked Inside
It’s cool to get a sense of the scale of the container. I’m always reminding people that when we look at buildings in process we’re generally looking with an outdoor perception. I find that as finishes go in and the walls close this funnels down to feeling quite small.. only when furnishing and indoor scale are replaced does it breathe back and enlarge. We’ll park in here but I’m excited to polish the concrete floor, paint it all white and be able to use it as a rec space some days. The shadow in the back foretells the light spill we’ll have down the stairway from the skylight above:
Bedroom Hall Mid Afternoon looking towards NW corner
Note the shadow from the corner is similar to above. I like the variations in the color of the light the 3 angles (skylight opening, sunlight at wall, window to north) produce.
Mockup4Sketch of View From Street
Couldn’t resist some more photoshop to scale the coming framing onto the existing concrete. I love the idea of knowing the angle of these shadows over the years to tell time. Bored during a Nantucket winter framing a house, I’d often place a nail out of the way on the plywood deck and mark a line for lunch.
It looks like they’ll be installing the permitter drain in a couple of days for our next inspection Monday or Tuesday, and then to the long chore of backfilling the wall.
1I like thinking of this very slow cycle movement of materials-I won’t forget the well worn marble marble steps of my English building in high school. It’s a good corrective in general to try and picture it built at least 20 years out, be it a detail or design.
2What great names these guys have.
3Upon graduating RISD I encountered a collapsed marketplace for graduating interns, and decided I’d liked his vibe in The Trial of Tilted Arc so much I should just go and work for him. It was easy to find his number in the white pages. And my then girlfriend’s roommate’s then boyfriend, from a steel mill family in Louisville, was his assistant. When I called his house I soon heard his muffled reply through his wife’s hand “Tell him I’m not here”. Three years later I was overseeing the space-shuttle-ceramic-tile-modeler defining the silhouetted edges of Disney Hall on the computer and sharing his “operating time” with this pugnacious guy, in the FOG office to use the software to numerically instruct a submarine factory in Japan to craft his torqued ellipses.
4The balcony’s a bit janky here and the CMU’s at the side will be covered. It will all benefit in being softened by the corduroy effect of the corrugations, and I expect the underside of the balcony to appear lighter. I’m fine with the limitations of this kind of rendering as the last few percent that makes it really real takes time and technology I don’t have.