framing the facades

the next williamsburg?

An interesting article about the attraction of our Bushwick neighborhood.  But we sincerely hope that Bushwick is able to hold onto all the great things that make it Bushwick.


Next Williamsburg: Bushwick, Brooklyn | Crain's New York Business
Six years ago, when Paris Smeraldo and Meg Lipke opened Northeast Kingdom in Bushwick, their menu featuring everything from $9 veggie burgers to a $23 braised lamb dinner was a bit of a reach. The area was still not the sort of place that drew many diners.

Even today, large swaths of Bushwick remain industrial backwaters, but the fact is that Northeast Kingdom, a 28-seat location at 18 Wyckoff Ave., is thriving in surroundings that have become more hospitable and even trendy in recent years.

“It's incredible,” said Brooke Hoffine, the eatery's manager.

The change is indeed dramatic. In the last year alone, three cafés, two bars, one art gallery, one organic grocer and several other retail businesses have opened. And more are on their way, as people stream in from neighboring Williamsburg and other areas in search of a meal, a drink or just a look around, and as artists and others take up residence.

The main reason they're moving in is simple: Bushwick is relatively convenient to get to, and it's cheap. While the average one-bedroom apartment in Williamsburg rented for about $2,400 per month in 2010, the average one-bedroom in Bushwick went for about $1,300. And while that sum is up 63% from an average of $800 four years ago, it still represents a New York bargain.  read more here......

concrete is cast

troweled smooth finish

Yesterday the concrete was pumped in and the floors were cast!  A crew of ten guys in boots shoveled, raked and troweled smooth the 4" pour.  Bear in mind this is the sub-floor.  Next radiant heating tubes will be laid out for the radiant floor heating system, and a second cast will be polished as the final finish floor.

a view from above

yes, that is a manhattan view from the roof!  and yes we have a roof now.

ridgewood reservoir in the distance to the southeast.

the rite joists

Wood or Steel? For us it was an obvious choice to go with steel. A condo building of our size by code requires that it be non-combustible, and with cast concrete floors (with radiant heat, ahhh) our floor framing needs to accommodate the weight.  So what's so special about our joists? These are MarinoWare Joist Rites, very different from the typical light gauge metal joists.  While they are a bit more expensive, they offer the ability to bear heavy loads, with a higher strength to weight ratio.  They have large elegant openings that contribute less to thermal bridging as there are fewer conductive pathways, and provide avenues within the floor cavity to run mechanical, plumbing and electrical conduits. In addition, their recycled content is above industry standards, and they are manufactured in New Jersey, locally.  

From a sustainability perspective, there are quite a few factors underpinning materials selection - embodied energy, recycled content, recyclability, place of manufacturing and harvesting, durability, lifespan, ease of installation, and ability to meet codes. Steel joists are straight, allowing for ease of leveling; do not warp, mold or rot; are light weight, allowing other structural members to be smaller; do not burn; allow for flexibility in design; prevent trees and their carbon sink from being removed; requireno chemical treatments; are easily recycled; and typically contain recycled content of around 25%.

BUT, steel joists have a higher embodied energy than most other options, with 35MJ/LB without recycled content, and between 8.9MJ/lb to 30MJ/LB depending on recycled content(1).  This compared to wood at 10MJ/LB is a significant issue.  What is embodied (or embedded) energy?  It is an energy assessment of a product, taking into account the energy required to extract its raw materials, plus the energy for primary and secondary manufacturing, sometimes including transportation.  A problem with these calculations, is that there is not a standard by which companies, or organizations follow, so we are often not comparing apples to apples.  In addition, the embodied energy is not a life cycle calculation, which would account for the lifespan of the material, and what happens after the use.  Once again, Lifecycle is also not standardized. The lifecycle of steel joists is better than that of wood because of its ease of recycling, and its longer lifespans.

A few stats about Joist Rite : Total Recycled Content: 32.7%, Post-Consumer Recycled Content: 25.5%, Pre-Consumer (Post Industrial) Recycled Content: 6.8%

The roof joists going in on the fourth floor.          

Rivet holders with brass rivets used to connect the 

joists to the framing members.

1. Comparing the Environmental Effects of Building Systems, Wood the Renewable Resource Case Study No.4, Canadian Wood Council, Ottawa, 1997

the path of least resistance

As the fourth floor finishes up, and a roof over head is actually in sight, we think its a good time to talk about, in architect's terms - the envelope - or the exterior wall (and roof) of the building. Althoughthe least sexy and often overlooked, the wall assembly behind the finishes is the most critical aspect in the creation of a sustainable, energy efficient building.  Over the past several months we have focused on the specifics of insulation, thermal bridging, air sealing, and structural detailing, all of which go hand in hand.  Since this is a LEED for Homes project, we are required to undergo an energy analysis - more details on that in a future post - which has helped us review and clarify our envelope's strengths and identified possible weaknesses to reddress.

A quick overview of our structural systems, which for NYC are pretty standard -  8" concrete masonry unit (CMU) bearing and shear walls, with light gauge steel floor joists (a whole post just on our joists is here) and a composite metal deck and concrete subfloor.  Diverging from the standard NYC floor section, the finish floors will also be poured and polished concrete (yeah! we are very excited about having exposed concrete finished floors in our apartments), but this layer will be thermally and acoustically isolated from the subfloor, as they will contain the tubing for radiant heat (more on that to come).  The front and rear facades are framed with light gauge metal studs.

Among the several limitations imposed on a building by its location within an urban context, the one that has the greatest effect on energy performance is the inability to site the building to maximize passive heating and cooling strategies.  Unless it’s a fortunate coincidence, the building cannot orient toward the south for winter heat gain, nor toward the wind for ventilation/cooling. Therefore the building must rely on a high performance envelope, with lots of insulation and a continuous airtight barrier to minimize the transfer of heat and air, respectively.  The most effective placement of these layers is on the outside surface of the building so that they create a continuous “overcoat”, thus eliminating any thermal bridging.  

So what is thermal bridging? - it is a path within a building envelope along which heat energy is transferred. To prevent thermal bridging insulation and thermal breaks are installed to break these paths of least resistance.  Ideally a continuous layer of insulation creates a thermos effect through the "overcoat" concept- keeping in the heat during the cooler months, and out during the warmer months.  The most typical parts of a building where this transfer is greatest is along metal studs, metal joists, and steel connections, where they attach to the CMU bearing walls, easily finding paths to the exterior. In the trout house, we are using a redundancy of insulation and air barriers, placing them on the exterior to achieve the overcoat concept, as well as within and on the interior of the building structure.  As described above, we have two different types of wall construction – CMU at the sides of the building, and steel studs at the front and back.  Although more insulation can be placed in the cavity of the steel studs, giving a greater R-value or total insulation value compared to the CMU wall, the effective, actual performance of the two wall assemblies will be comparable, due to the high conductivity of the steel studs, and the ability of the CMU to absorb and slow down heat transfer process.

In recent years with more and more people writing, blogging, and talking about sustainable, net-zero, energy efficient design, the general principles of a well sealed building have started to take root. But before insulation or the air-sealing, during the structural phase addressing thermal bridging - which can be an even more powerful energy drain - is even more critical.  When building ground-up, we have the advantage of getting it right the first time around.

Below is an image that shows one example of where thermal bridging needs to be controlled - at balcony connections.  Although not apparent in the photos, the steel framing for the balcony and the steel framing for the floor are independent and separated structurally.  Therefore when the concrete is poured over the metal decks, the floor slabs will also be isolated from each other.   However, we still need to go a step further. The image on the left shows an improper installation that needs to be remedied : concrete infill in the center creates a themal bridge between the steel of the floor and the steel of the balcony.  This will be chopped out, and a line of insulation will be installed to create a break.  The image on the right was installed correctly, leaving a gap where insulation can fit in.

Insulation and air-sealing are additional important construction methods for ensuring energy efficiency.  While its important that the architectural drawings and details are clear and well designed - the execution in the field is the Achilles heel.  Short cuts, not understanding the basic principles, mistakes, and language barriers all add to construction that does not meet energy efficiency standards.  Recently Urban Green, the local chapter of the USGBC launched G|PRO to help contractors and maintenance crews - important but overlooked professions - get to understand their role, and techniques for building green.  More details to come when the insulation gets installed…….soon. 

june progress: 4th floor