We submitted our proposal for an affordable accessory use housing competition in Wellfleet, MA. It called for the design of a small freestanding building on the same lot than an existing home. It’s an attempt to create affordable living spaces for year-round residents which get priced out by the Summer crowd. (hello Hamptons!) The area is blessed with mid-century modernist buildings by architects like Marcel Breuer and Serge Chermayeff among many others.

More information on the competition website  and on the website of the Cape Cod Modern House Trust.

Update: We and 5 other teams were selected for phase 2 which includes a 1 week residency in one of the 2 houses of the trust this summer…very happy.

The project description:

Our design proposal seeks proximity to the modern architectural history on Cape Cod. The simple rectangular shape tries to appear weightless being cantilevered over a small base. Looking from South, the main volume is floating among the existing trees.

The facade siding creates a linearity by underlining the horizontal appear-ance. Shape and size of openings are a reaction of the relationship bet-ween inside spaces and outside surroundings. The large south facing windows capture the view across Wellfleet harbor and provide passive solar heating in winter.

A recessed balcony defines the south-west corner of the living space. Summer shading is provided through external louvres and a sun-sail above the cut out.

The two story structure is located in the rear of the property with its own private entrance separated from the main house. The concrete base occu-pies a small footprint to reduce excavation and the size of the foundation. It houses a vestibule with storage closets and the mechanical room. A single stair leads to the living and sleeping areas upstairs. The walkthrough bathroom is located next to the kitchen to simplify plumbing and could also be used to access an optional second bedroom.

The second floor structure is made out of 5-7″ thick Cross-Laminated-Timber panels making the cantilever easy to built. It creates an entrance area which could be used as a covered outdoor area or a car-port. The proposed building shell is well insulated with 6″ of mineral wool, all joints are sealed with airtight tape.

For heating and cooling we propose a small ductless air-to-air heat pump.

Fresh air is supplied by one pair of oscillating through-wall fans with heat recovery. Rain water is collected at the back wall and used for flushing, washing and gardening. Hot water is provided by an electric heat-pump water heater.

This simple, small and affordable free-standing dwelling unit combines minimalistic modernism with sustainability and green technology.

thanks to Raimund Koch

…it’s doors to the public tomorrow, Friday at 6pm.

It has been our first experience working with cross-laminated-timber panels and it was a great experience all around. The box, as we call it, is 54′ x 12′-6″ x 19′-6″ high and weighs about 50,000Lbs.

It took the nice and capable guys from Bensonwood (out of NH) only 3 days to assemble it. Most of the CLT was left exposed and was just sealed with OSMO oil.

All electric installations are surface mounted. The openings were closed with a Modulit500 / glass combination installed by Bopart-NY.

General Contractor: Deary Construction

Reception desk: Hooked on Wood

Metal work: Andreas Padazo

Floor: Hudson Concrete Polishing

Electric: Claude Martz

This project is a collaboration with Dominik Dippelhofer.

Great team!

We recently began the conversion of an existing Williamsburg warehouse into The Journal Gallery, in collaboration with Dominik, the brother of one of the gallery owners, who is an architect in Luxembourg. While the project is a nice fit for us in and of itself, with it’s rough & clean aesthetic, what makes it even more interesting is the fact that we are using Canadian-made Cross Laminated Timber panels — it’s not only our first time using this material, but it’s in fact the first time it’s being used anywhere in New York City. It has been an exciting process but also a challenging one, in particular for 2 reasons: First in finding the CLT panels, and then in getting them approved by the Department of Buildings, who had never seen them before.

We posted a question on the website greenbuildingadviser.com and the very knowledgeable and helpful community pointed us in the direction of the Quebec based company Nordic. The firm has been around since the 1960s and produces a wide number of engineered wood products. In 2011 they started to produce their version of CLT products.. Here a link to the announcement of the Nordic website… where its explains the advantages of this fantastic material.

The next step was to get wood construction approved in NYC, where we have a super strict fire code. The good news is that the 2008 building code lists Heavy Timber as an allowed construction material with certain limitations. (Table 601: Type IV)

Lastly, we even found a contractor who has experience with the assembly of this new construction material!

Bensonwood from NH
Scheduled delivery is of the off-site, CNC-cut panels is next week…we are excited!

update: for more info about CLT watch this good promotional video 

these are the first sketches of how we’d like to convert the ugly 60′s garage into a modern passive house townhouse in a landmarked district… hopefully we’ll be lucky with the LPC… before you tell us that we are crazy to propose something like this in a landmarked area, please look at this nice image of a traditional shutter which can be found in typical Brooklyn brownstones… we are just mounting the shutters on the outside of the building, for 2 reasons: to give the interior some privacy, and with careful design of the louvres we can cut down on the scorching nyc summer sun…

…needs special attention. From the communal heat pump hot water heaters with individual flow meters to insulated roof drains. One major improvement is that the NYC 2008 Plumbing Code now allows PVC over cast-iron piping which makes for smaller thermal bridges through the envelope. Some would say these drawings are boring but they mean a lot to us! Click on the red arrows to find out more…

Thanks to Sasha from Klein Levin Consulting Engineers for all the patience!

Most of our new projects have no connection to the City’s gas piping, so we need to find an efficient way to produce hot water. First we were thinking about a solar thermal system with electric resistance backup, but the more we learned about it the more we realized that they are quite complicated: They need a pump to circulate the water from the panels to the storage tank, plus need to drain at low temperatures so the pipes don’t freeze… and in summer they can overheat. Here is an excellent overview at GreenBuildingAdviser.

Next we looked into Electric Heat Pump Water Heaters. We previously used a 50 gal GE GeoSpring on our project at 174 Grand St, but we then found that the US branch from Stiebel-Eltron sells the 80 gal Accelera and A.O.Smith the 80 gal Voltex.

While reading up on the specs and differences of the 3 products we found a field test done by Steven Winter Associates. It turns out that the Stiebel-Eltron outperforms it’s competitors with an average Coefficient Of Performance of 2.40. To be fair, it has to be said that the Accelera retails for $2,500 and is the most expensive of all 3.

In an attempt to keep the system affordable  we decided to go with a communal solution where all 7 apartments get their hot water by three 80 gal heaters which have a parallel connection and are located in the unconditioned basement — one of the known advantages of heat pump water heaters is that they dehumidify damp basements. If it turns out that the total 240 gal capacity is not sufficient, it will be easy to add another heater… and if one breaks, the building will not be not without hot water.

We still have to decide if we will install BTU meters to measure the individual usage.

If you have any questions or suggestions, we’re all ears: hello@loadingdock5.com

Links:

Here the complete report

Stiebel Eltron Accelera 300

AO Smith Voltex Hybrid

GE GeoSpring

We had a kick-off

meeting with our MEP consultant Benjamin Klein and I will try to summarize (before I forget everything which was discussed!):

• Heating / Cooling: Each apartment has its own ducted air handler (12,000BTU Mitsubishi), but we might have a combined 6 ton condensing unit on the roof. Here the link.
• Each apartment can have its own temperature setting, but we’ll have one shared bill which we’ll have to subdivide by apartment size (judged by square footage). The main reason for this solution is that one big condenser is a great deal more efficient at low temperatures, which translates into an even lower heating bill. It’s also simpler to maintain one unit vs 7 or 8 units. We would probably be fine with less than 12k BTU, but that’s as small as they get. Additionally, the pump runs with variable speeds so it is able to scale down it’s heating/cooling output without losing efficiency.

• Fresh air:Each apartment will get its own Energy Recovery Ventilator (Zehnder ComfoAir200), which will be independent from the ducted air handler to keep things simple and to avoid negative interaction between the individual fans. One simple solution for avoiding double ducts would be to have the air handler supply in the living area and the ERV supply in the bedroom. ERV return in the bathroom, and AH return just outside the bathroom. The supply air out of the ERV is a couple of degrees colder than the design temperature, but this might even be welcome because it’s a bedroom. Both units are hidden in the ceiling above the bathroom but accessible.

• Fresh air UPDATE: We will have two ComfoAirs550 in the unconditioned basement supplying the apartments with fresh air. There are some advantages to this simpler approach: it’s less expensive, the filters are accessible  from a common area and can be serviced by 1 person, there is less room for human error due to the wrong settings of the HRV (download the user manual here to see that they are quite complex to operate) and we have almost no duct losses.

If you like to see more about our Haus here is the link…

We started working on the conversion of a good ol’ Brooklyn warehouse into a single family Passive House residence. The existing structure was built in the 1960s and is a commercial building in the residential part of Williamsburg. The design concept is quite simple: We propose to create a courtyard to bring in natural light and also serve as a divider between the living area and the work studio. The small roof extension houses the bedrooms and bathrooms. We were careful to keep the addition low in order to bring sunlight into the courtyard year-round, particularly the low winter sun for, you know, solar gain…

The challenges ahead:

- How to insulate the existing CMU structure to PH standards. We can’t add more than a couple of inches on the exterior because it is a lot line.

- We would like to keep the street-facing brick exposed, so we will need interior insulation in this area at least.

- We would like to leave the existing wood joists exposed, so how will we air seal the roof area?

- The existing parapets will have to be extended because of the increased thickness (min 8″ insulation and min 6″ for the green roof). To avoid a thermal bridge we will probably use Autoclave Aerated Concrete.

(this list will continue to grow…!)

It took us a while to decide which structural system we should use for our new building. In the end, we went with an “Insulated Concrete Form“ which is made out of cement-bonded wood fiber. Wood fiber, instead of polystyrene! The product is called Durisol -it’s a Dutch invention from 1932 and was widely used to rebuild European cities after WWII.

We were delighted to find out that there is a plant that makes it in Hamilton,Ontario.

Here’s is a list of reasons why we went this way and did not use regular polystyrene ICF’s:

* Most common ICF’s are out of Expanded PolyStyrene. While we have a few concerns about the durability of the foam, we just don’t like the fact that with a regular ICF we have 50% petroleum-based foam in the interior of the building.

* The symmetrical build-up of the insulation of regular ICF’s creates a thermal bridge by tying the floor-slabs structurally into the concrete core. Durisol forms have the majority of the insulation on the exterior where it should be.

* The company claims an R value up to 28 for the 14″ thickness with 5″ mineral wool in the cavities which is sufficient. (Conservative PHPP modeling came closer to 25, but that’s still good enough for this Passive House.)

* The interior surface of Durisol doesn’t have to be covered with a layer of Sheetrock–it can be stuccoed with clay, which should help balancing humidity levels.

* The higher weight compared to EPS blocks seem to help to prevent blow-outs during pouring of the concrete.

Our building has a simple envelope of 51′ long by 25′ wide, and it’s only 4 stories or 40′ in height. Normally this shouldn’t not pose any serious construction challenges but we building a Passiv Haus so certain areas need special attention. Here a (not yet) complete list:

* The cellar is outside the treated envelope but we still need to verify if it is enough to insulate the foundation walls or we still need to add a couple of inches of high-density, insulation-like foam glass under the footings.

* The two parts of the forms are connected by wood fibers and while this is great to avoid thermal bridging we still have to find a solution for applying the air-tight layer on the exterior, which is particularly difficult at the side-lot lines where we have existing buildings. So far, we are leaning towards a liquid applied membrane.

* Balconies built by cantilevering floor slabs are massive thermal bridges and so we are looking into a steel frame with wooden decking solution hung from the exterior walls with aircraft cables and stainless steel anchors.

* Roof parapets should not be filled entirely with concrete but foamed out in the last 4-6 inches (another thermal bridge).

After talking to very helpful person at the company we even came up with an estimated price for the exterior wall of $40,000 including delivery to Brooklyn. Here is a link to the Canadian Durisol website which has detailed technical information.

PS: it seems that this simple building requires some creative solutions from our structural consultants (especially the interior stair) so a loud Thank You to them!

Update:

Faswall is a Oregon based competitor with a very similar building system.