Small Lot Legislation

Last fall the Seattle City Council put a moratorium on the creation of small lots in single-family neighborhoods. Now they’re revisiting the issue, to develop permanent legislation regulating houses on small lots. In their words the City “supports infill development in single family neighborhoods, including on legally established undersized lots. However, these lots should be clearly and legally delineated, and neighbors should be aware of the potential for new houses to be built. In addition, new houses on undersized lots should be modest enough to be proportional to the size of the lot”.

The DPD (Department of Planning and Development) offered preliminary recommendations, which the Council is reviewing: http://buildingconnections.seattle.gov/2013/03/20/preliminary-recommendations-for-developing-small-single-family-lots/

The local CORA group (Congress Of Residential Architects) developed our own response to this pending legislation. An important part of this proposes to replace the Mid Block, as the small lot development area of choice, with Corner Lots. If the City allows outright for corner lots to contain two houses, it would at the same time provide the additional development potential Seattle needs, in a way that actually IMPROVES those neighborhoods. As noted in the Walkable Livable Communities presentation I developed with some NW Ecobuilding colleagues, double houses on corner lots take those qualities we love about single-family neighborhoods – i.e. the opportunity for social engagement with neighbors (while doing yard work, taking a stroll, sitting on the front porch watching passersby, kids playing on the sidewalk, even just getting in and out of your car), the benefit of eyes on the street/added security, the architectural/aesthetic benefit of front facade/front porch facing the street, etc. – and extends these qualities to the side streets. The before and after sketches below illustrate this:

re-zoned corner lot

David Neiman, who’s led CORA’s efforts to critique the City’s proposal, argued our case on KUOW’s The Conversation (he calls in around 20:00).

Passive Solar

Passive House, or passivhaus, is sometimes confused with passive solar, and although the latter is an important component in Passive House design, the terms are not interchangeable.

Passive solar refers to the strategy of using the building itself – the windows, walls, floors –  without added equipment, to collect, store, and distribute solar energy as heat. A part of passive solar design is also the control of unwanted solar energy in the summer, through the use of overhangs etc. The idea of passive solar contrasts with active solar, which uses equipment (e.g. photo-voltaic panels, or solar hot water collectors) to do the same.

Passive solar requires thoughtful consideration of the local climate, solar access, building siting and orientation, landscaping etc.

There are several types of Passive Solar. The first, and most basic, is Direct Gain, where the interior space is heated directly through south-facing windows (of course this assumes the building is located in the northern hemisphere).

 

 

 

 

 

 

 

In Indirect Gain, a thermal mass, for example a “trombe wall”, is located between the south-facing windows and the space to be heated. The advantage in this method is that the transfer of heat to the interior is delayed, so a thermal mass heated during the day may release its heat to the interior at night.

 

 

 

 

 

 

 

The third type is Isolated Gain, using a separate Sunspace, or Greenhouse, to borrow heat from as needed.

Some Passive Solar Fundamentals:

  • Orientation – if possible, orient the long axis of the building in the east-west direction, to maximize southern exposure. Ideally there will be unobstructed access to the sun during most of the day, and the principle use spaces of the building will be located on the south side, with service spaces (e.g. example bathrooms, mechanical, storage) on the north side.
  • Windows (free solar heat generators) – in general, optimize the amount of windows on the south side of the building, and minimize the amount of windows on the other three sides.
  • Control – use the architecture itself (eaves, awnings, exterior shades, sliding screens etc.), to block summer sun, but allow winter sun to penetrate interior. The latitude determines the ratio of depth of overhang to height of glazing. You can also use the landscaping for control. Deciduous trees on south side can block unwanted summer sun, but allow the winter sun to pass through. Evergreen trees on the east and west sides can block unwanted solar gain.
  • Thermal mass – Thermal mass refers to a material that can absorb the solar heat that enters a building – it can be an exposed concrete floor, ceramic tile, even gypsum wallboard.
  • Distribution – Thermal mass distributes the heat by radiation; In indirect or isolated passive solar, distribution can be by radiation, convection, or assisted by mechanical means.

Some Passive Solar Challenges:

  • Passive solar design guidelines often assume a large, flat, unobstructed site with no trees. In urban areas, lots oriented east-west typically have (sometimes tall) neighbors tight to the south, while lots oriented north-south will have a short face on the south side, neither of which is ideal. Sites on north facing slopes are not ideal – sometimes the site itself can block the sun (esp. when the sun is low in winter, when you need the solar gain the most). Conversely, sites on south facing slopes are preferred.
  • Seattle homes are sometimes designed as “View Machines”, and often that view is to the west – maximizing windows for view can be at odds with passive solar ideals.
  • Shading or screening of south-facing windows, to minimize summer heat-gain, can make rooms darker in our already gray winter months.
  • Remodels – passive solar design guides often assume you’re building a new house from the ground up, and so have more opportunity for optimal siting, orientation etc. A remodel or addition project has more constraints, e.g. existing architecture to relate to, structural issues that may make large areas of glazing difficult, etc.

That being said, an existing house can be remodeled to incorporate passive solar strategies, e.g. adding more windows on the south side, adding awnings over south facing windows, or adding thermal mass on the interior.

Without going into detail, I’ll list a few innovative ideas relating to passive solar design:

  • Annualized geo-solar – this refers to capturing warm season solar heat and storing it for several months, until it’s needed in the cold season. A variation on the Thermal Flywheel idea;
  • Phase change materials – usually eutectic salts, materials that store solar energy as latent heat. The sun heats and melts the material during the day – at night the material reverts to a solid state, and the stored heat is released. Phase change materials can be incredibly efficient in storing heat – as much as 80 times as effective as water;
  • Living Walls, depending on the plant type, can allow winter sun through, but will block the sun when it’s filled out in the warmer months;
  • Planning for future active solar – I like to think of this as another passive solar fundamental. Configure the roof to maximize solar orientation and access for potential future PV and solar hot water systems. In projects not installing a solar system, pre-pipe for future installation.

The heat-gain benefits of passive solar design should always be complemented by strategies to minimize heat-loss, such as adding insulation (beyond code), using high-performance windows, making the building super air-tight, using an HRV, using high-efficiency lighting, plumbing fixtures, appliances and systems, etc. This meshes with the goals of Passive House (you knew I was going to circle back to that, didn’t you?) – to equalize, as much as possible, the heat loss through the envelope of the building, with the heat gains, both external (solar) and internal (peoples bodies, appliances, lighting, etc.).

Recent Projects Update

I’d like to take this opportunity to show a couple of recently completed projects. The first is a Backyard Cottage, my second completed since Seattle’s Backyard Cottage Ordinance was approved 3 years ago (I have two more in the planning stage). The second project is a modern addition to an old Tudor style house.

 

Green Lake Backyard Cottage

This project is a new  Detached Accessory Dwelling Unit (DADU) in the backyard of a house in the Green Lake neighborhood of Seattle. Driven by the program, this cottage had to completely max out the allowable square footage (800 s.f.), and the maximum roof heights (16′ on the low side, 20′ on the high side). Spatially, the building was shoe-horned into the allowable building envelope, and just barely allowed comfortable ceiling height at the top of the stairs. In the end, what was created was an efficient but comfortable open living space, with gracious bedrooms and baths.

The cottage includes 2 bedrooms, 2 baths, a kitchen and family/dining room. It can be re-configured as needed to provide a separate one-bedroom rental for a tenant, and an extra bedroom for the main residence. The project had a modest budget, but because of the small size allowed the owners to splurge on the bathroom and kitchen finishes, and exterior elements such as the galvanized steel canopies.

The siding is a mix of cedar, and cement-board siding, installed in a rain-screen fashion over rigid exterior insulation, which acts as a thermal break. The outdoor court is technically a parking spot (accessed from the alley), but is not used as such for the current tenant. A mechanized sliding gate can close off the court from the alley.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The main floor bedroom includes a space-saving Murphy bed, with a fold-down table to make the space even more versatile.

 

 

 

 

Ravenna Addition

This project was a rear yard addition to an existing 1920′s era house in the Ravenna neighborhood. The addition included a master suite downstairs, and a family room off the existing kitchen and dining areas upstairs. The existing kitchen was remodeled too. A roof terrace was added off the family room. The work to the existing portions of the house was kept to a minimum to help stay within a limited budget.

 

The homeowners wanted their addition to be in the modern style, but did not want to change the appearance of the house from the street. On the interior too there is a striking change in style between the old and new portions, delineated by the new beam separating the two.

 

A frosted glass railing helps diffuse the light, both natural (during the day) and artificial (at night – a pendant light is centered in the stair well behind), throughout the space.

 

The stair wall consists  of a cabinet that provides dense storage on all sides – at the main floor, on the stairwell side, and at the bedroom below.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The basement floor is a heated concrete slab. A sliding barn door shuts off the bedroom from the stairway.

 

It’s been a few weeks since my last post, due to a combination of a flurry of new work, and some technical glitches I’ve had to work through. I apologize – it won’t happen again!

City View: Seattle Design Reveals Natural Wonders


Walkable Livable Communities

A few years back I developed (along with Sheri Newbold and Justin Fogle, fellow former Presidents of the Seattle Chapter of the Northwest EcoBuilding Guild) a presentation describing the benefits of allowing increased density in Seattle’s single-family neighborhoods. We called it Walkable, Livable Communities, and we gave our presentation to several community groups, policy makers, and agencies.

In brief, the presentation boiled down to the following:

  • Seattle is destined to grow substantially in the near future;
  • That growth can be sustainable, and occur within the city limits, or it can be unsustainable, and lead to more sprawl;
  • Most of the developable land in Seattle is currently zoned single-family;
  • We proposed that the City allow more variety within single-family neighborhoods, to let a good part of the predicted growth happen there (by “variety” we meant such things as: cottage developments, retail on corner lots, duplexes, triplexes, apartment buildings, mixed housing types adjacent to one another, etc).*

The diagrams below show how the idea of sustainability in regard to cities has evolved over time – in both scenarios, red is bad. The old way of thinking, illustrated on the left, shows CO2 per square mile, more concentrated in the denser urban zones than in the outlying areas (so, cities are BAD).  Cities were considered unpleasant, dirty, polluted, and unsafe. The diagram on the right shows CO2 per household, and from this perspective cities are GOOD.

CO2 per household diagram

The chart below shows the density per square mile of several cities, including Seattle.  Clearly Seattle is less dense than many others, including Los Angeles, which is usually thought of as a sprawling, less dense urban area.

density per square mile of several cities

Density is a loaded word and concept, and has negative connotations for some people. Part of this negativity (sometimes called NIMBYism – as in Not in My Back Yard) might be explained by the prevalence of poorly designed, poorly built condo developments, which people may envision when they hear the term “density”. Because these often happen on the boundary between SF and MF zones, some people think they’re allowed in Single-Family neighborhoods.

Some people fear that increased density will lead to lower property values. This is often expressed as an aversion to rental properties, or the feeling that renters have less incentive to maintain their homes and yards.

Parking, of course, is a controversial issue, with the concern that increased density will lead to more parking congestion and traffic. This is a chicken and egg question – since increasing density and potential public transportation ridership, and encouraging local businesses, will lead to less need for automobiles.

Others fear that higher density will make neighborhoods less safe and secure. As with really all of these concerns, it’s more an issue of good design than density per se.

Our presentation pointed out that the zoning we know today is a relatively new concept. In the past different uses and densities were allowed together, on a block by block basis. Only later did we establish the division of zones that we see today – large swaths of area for one kind of use only. We can still see traces of the old zoning (or lack of zoning) in areas – in existing buildings and development patterns that would not be allowed under current code. Here are some small retail spaces at a corner lot in Capitol Hill currently zoned SF:

corner lot in Capitol Hill currently zoned SF

Cottage housing was built in single family neighborhoods in Seattle to create affordable housing, or housing that met other needs. These are the Pine Street Cottages built in 1916, and renovated in the 90’s.

Pine Street Cottages built in 1916, and renovated in the 90’s

This is an older duplex in Queen Anne:

older duplex in Queen Anne

A triplex in Wallingford:

triplex in Wallingford

And a fourplex on a 4000 s.f. lot in Queen Anne, currently zoned single-family.

fourplex on a 4000 s.f. lot in Queen Anne, currently zoned single-family

The photo below shows two lots in Ballard, each 2500 square feet. This would not be allowed today, in this SF 5000 zone.

two lots in Ballard, each 2500 square feet

The drawings below show a typical corner lot (on the left), and a re-zoned corner lot (on the right), which illustrates the condition in the above photo. We propose that this be allowed again, that existing corner lots can be subdivided. An advantage to this would be allowing the single-family character of the residential neighborhood (pedestrian activity, visual interest, eyes on the street etc.) to wrap around onto the side streets as well. Incidentally Portland allows duplexes outright on corner lots.

re-zoned corner lot

In addition, there are some new ideas that would allow more housing in single-family neighborhoods, and give homeowners more options, in ways that could maintain the scale and character of those communities:

A Flex House adapts over time to respond to its owners’ changing needs. For example, a young couple may move into the upper floor of their Flex House (as illustrated below) and rent out the lower floor. When they start a family and need more room, they take over the whole house. Then, as their kids grow up and move out, and the parents become less mobile, they can move into the lower floor and rent out the top. The nice thing about this idea is that, along with adapting to match the owners’ needs, it would encourage people to stay in their homes longer. The Flex House would require zoning codes to become more resilient, and able to be altered over time for particular lots.

Flex House adapts over time to respond to its owners’ changing needs

Many of the ideas we’ve discussed are not new ones – as shown, almost all were legal inSeattlein the past. These can benefit homeowners, by giving them more options for their property, to accommodate extended family, or bring in extra income. They can accommodate a good part of the projected growth thatSeattlewill experience, and offer many of those new residents a broader variety of housing options.

Zoning terminology has changed over the years – remember “Single-Family” zoning is a relatively new idea. Maybe it’s time to reclassify our in-city residential neighborhoods – not as “Single Family Residential”, but just…”Residential”.

*Incidentally, this presentation initially included Detached Accessory Dwelling Units – the City has since passed the Backyard Cottage Ordinance.

 

Simple Modern Upgrades

With a few simple improvements, a drab old house can become beautiful. Often clients come to me looking to upgrade an older home, not just aesthetically, but also functionally and structurally. I won’t get into the structural aspects here, and functional improvements usually involve turning a compartmentalized, inefficient floor plan into an open, well flowing layout through the opening up of walls, improving relationships between spaces etc. Or adding on to an existing house to gain square footage, and at the same time making improvements to the existing spaces.

Aesthetic upgrades are the subject of this post. These can range from a major second story addition, which completely changes the look of the house both inside and out, to a very simple and cost-effective “facelift”. Following are some examples, which show before and after photos, and describe the scope.

This project took a boring flat roof box and dramatically updated it. The only addition was a 70 s.f. penthouse, to access the new roof deck. The interior was completely reconfigured, and the exterior was re-designed to draw attention to the new solar array on top. The siding was installed in a rainscreen fashion:

This shows the rear of the same house – as in front, the remodel simplified the structure, and opened up the house to the view:

This very small remodel was strictly an exterior facelift. The owners felt the front façade lacked character, and wanted to cue visitors how to find the side entry. Through the addition of some corner windows, and wrapping the wood siding down and around to the front door, the design successfully improves the entry sequence, in a very cost-effective manner:

This project was a design/build spec project, a case study in green remodeling:

Yet another second story addition, this project minimized the work to the existing portions of the house, to stay within a limited budget:

This late 70’s house, which was comprised of several shed roof volumes competing for attention, was simplified by eliminating all but the main shed. The other elements were reconfigured to become either exterior terraces, or “flat” roofs, and three new siding materials (cedar, cement-board and metal) were introduced to differentiate the parts:

This is a second story addition that, while taking some cues from the existing house (e.g. the stone facing), is a strong modern departure from the original traditional structure:

Rain-Screen Siding

Rain-screen siding is an exterior assembly which holds the finish siding away from the surface of the drain-plane of the wall, creating an air space between that allows for ventilation.

Prior to the energy crisis in the mid-seventies, buildings tended to be leaky, and allowed a lot of air-flow through (i.e. between the outside and inside of) their wall cavities. Later, when buildings were tightened up to save energy, this ventilation, and its ability to dry out any moisture that got behind the siding, was diminished. You may remember the rash of lawsuits in the late 80s and 90s, related to projects whose Dryvit (EIFS) siding failed – these were due to just this issue. EIFS systems now have to incorporate a ventilation layer behind the siding.

In houses, a conventional wall assembly consists of wood studs, usually at 16” on center (in new construction advanced-framing techniques should be used, with studs at 24” o.c.), drywall on the interior side, and structural sheathing on the exterior side of the studs. Over the sheathing (usually plywood or O.S.B.) a weather-resistant barrier (WRB) is applied – this can be asphalt-impregnated building paper, Tyvek or similar house wrap, or newer materials such as Vapro-Shield. The siding is then applied directly over the WRB. Any moisture that does find its way behind the siding in this assembly has virtually no way to get back out.

By contrast, in rain-screen the siding is held away from the wall. There are several reasons rain-screen siding is the preferred method for installing siding:

  • It causes any water that does make its way behind the siding to quickly evaporate;
  • It equalizes the pressure on either side of the siding. In a conventional wall, where the siding is tight against the drain-plane, blowing winds will create an area of high-pressure on the exterior face of the siding. Wind-driven rain can be forced to travel through (even up and over) the siding to find the area of relatively lower pressure behind. Once that water is behind the siding it’s trapped;
  • It improves the vapor-diffusion characteristics of the wall (more about this in a future posting);
  • It minimizes heat gain in the wall;
  • It discourages the buildup of moisture in the wall cavity (insulation and framing), which can lead to decreased R-value, and deterioration of the structural members. Water that does make it into the wall cavities tends to occur at especially leaky areas – even though buildings are tighter than they used to be, they’re still not tight enough!);
  • It discourages the buildup of mold and mildew, and associated indoor air quality (IAQ) problems such as asthma and allergies.

The rain-screen siding assembly is applied over furring, which can be 1 x 2 cedar strips, or proprietary metal hat channels with neoprene gaskets. These assemblies can be either closed-gap or open-gap. Closed-gap rain-screens don’t have to look any different than conventional siding, except they’ll have a vent at the top and bottom of the wall to allow the flow of air behind the siding. Open-gap rain-screens leave a visible space between the pieces of siding, which can provide even better airflow behind. Extra care has to be taken in detailing and spec’ing open gap systems, to properly discourage excessive water intrusion, insects, UV rays, etc. Variables that come into play are the depth of the siding relative to the gaps, the thickness of the furring strips (i.e. how far the siding is held off the wall), detailing the base and top of wall conditions, detailing the vertical gaps properly, etc. Often an open gap system will have exposed fasteners, which can become a strong element in the overall design, and can be very attractive.

Water will get behind siding, no matter what we do. Let’s accept that fact, and work with it rather than against it, by using rain-screen siding.

Pioneers of High-Performance Buildings

I’m inspired by pioneers in any field, but particularly those who were doing low-energy buildings long before most of us even heard of “Green Building”.

A little background may be in order. I remember in the early seventies when the oil embargo hit, and my parents complained about the price of gas jumping (the price of oil quadrupled from $3 to $12 a barrel!). A concern for energy efficiency and energy conservation grew out of this “crisis”. Energy codes were born or broadened, requiring us to insulate our buildings, and to make them less leaky. There was a lot of trial and error – two steps forward, one step back. Insulated buildings saved energy, and so did tighter envelopes. But the latter also led to the unhealthy build-up of toxins and stale air indoors (can anyone say “Sick Building Syndrome”?)*. In response to this, fresh-air ventilation was introduced. This led to more energy loss as the warm indoor air was exhausted, to be replaced by cold air from outside. In response to this, heat-recovery ventilation was introduced, which has become more efficient over time.

*There were other unforeseen impacts of these “improvements” – for example, tighter buildings no longer allowed the easy passage of water vapor through walls. More about this in a later blog!

The abbreviated history above describes the slow response (really still occurring) within the mainstream building industry, to the energy crisis. But there were those who took a more holistic view of building and energy, and from the start integrated many effective strategies together. One of these innovators (a hero of mine) was William Shurcliff, a well-known physicist with a background in nuclear physics. He issued a press release in 1979 (!), listing the necessary components of super-insulated houses. It reads today, 33 years later, like a checklist of strategies to achieve the Passive House Standard:

1. Truly superb insulation. Not just thick, but clever and thorough. Excellent insulation is provided even at the most difficult places: sills, headers, foundation walls, windows, electric outlet boxes, etc.
“2. Envelope of house is practically airtight. Even on the windiest days the rate of air change is very low.
“3. No provision of extra-large thermal mass. (Down with Trombe walls! Down with water-filled drums and thick concrete floors!)
“4. No provision of extra-large south windows. Use normal number and size of south windows — say 100 square feet.
“5. No conventional furnace. Merely steal a little heat, when and if needed, from the domestic hot water system. Or use a minuscule amount of electrical heating.
“6. No conventional distribution system for such auxiliary heat. Inject the heat at one spot and let it diffuse throughout the house.
“7. No weird shape of house, no weird architecture.
“8. No big added expense. The costs of the extra insulation and extra care in construction are largely offset by the savings realized from not having huge areas of expensive Thermopane [windows], not having huge well-sealed insulating shutters for huge south windows, and not having a furnace or a big heat distribution system.
“9. The passive solar heating is very modest — almost incidental.
“10. Room humidity remains near 50 percent all winter. No need for humidifiers.
“11. In summer the house stays cool automatically. There is no tendency for the south side to become too hot — because the south window area is small and the windows are shaded by eaves.

The developers of the Passivhaus Standard acknowledge their indebtedness to William Shurcliff, and other pioneers experimenting in super-insulated houses (many of whom were from the U.S. and Canada). Shurcliff wrote many books on this and related subjects, including “Solar Heated Buildings of North America”, “Thermal Shutters and Shades”, “Super-Insulated Houses and Double-Envelope Houses”, and “Air-to-Air Heat Exchangers for Houses”. More about Shurcliff, and others including Harold Orr and Eugene Leger, can be found at: http://www.greenbuildingadvisor.com/blogs/dept/musings/forgotten-pioneers-energy-efficiency

Seattle Green Design and Passive House Consultants

Jim Burton Architects, aka BLIP Design, is dedicated to the integration of sustainability and modern design.

Buildings should touch the land lightly (like a “blip” on the landscape).  Using this dogma, BLIP Design and Jim Burton incorporate energy-efficiency, materials and water efficiency, healthy home strategies, and environmental stewardship into each project.

Passive House

Passive House is a rigorous, proven methodology for creating ultra low-energy buildings. It uses a variety of strategies to ensure that the heat losses through the envelope are roughly balanced by the heat gains from passive sources, and thus eliminates the need for a conventional heating system. It is the most cost-effective path to Net-Zero Energy. Jim Burton is a Certified Passive House Consultant, and can help your project meet the Passive House Standard.

Backyard Cottages

With the recent passage of Seattle’s Backyard Cottage Ordinance, Detached Accessory Dwelling Units are now allowed throughout the City. If you’re looking for more space for a studio, for aging parents or boomerang kids, or extra income from a rental property, a Backyard Cottage may be just what you need.