Thursday, February 27, 2014

Refinishing the Concrete Floors

Finishing up the ADU construction in the summer of 2011, my partner and I were attempting to make tens of good, long-term design decisions about the final look and feel of the ADU. From the placement of outlets, to the colors and style of granite countertops in the kitchen, to how to build attractive built-in cabinetry in the bedroom cheaply, there was so much to figure out quickly.

Having never worked with concrete, I was at a loss about how to correctly finish the concrete. I went to Home Depot and found a concrete stain and was able to easily apply a beautiful, rich red stain to the floor with a roller brush. Then, I applied a sealant, and voila, within a matter of hours, the drab grey concrete was a glossy red. It looked awesome.

Fast forward 2 years, 6 months, and I was no longer so psyched about the wonderful looking concrete floor. Over time, the stain gradually wore off to the point where it diminished the aesthetic of the ADU. It was a cool process to observe where it wore off . Any guesses where the it came off quickest? Answer: The kitchen- where we apparently spend the most the time walking around.

At first, there were just little white nicks, but eventually, the concrete looked ragged. I was frustrated because I'd stained and sealed the floor, but I came to learn that the product that I'd used wasn't really an absorbent stain; it acted more like a paint. And, like paint, it eventually peeled off. 

In January, I decided to bite the bullet and re-do the floor altogether. I researched options on how to refinish concrete floors, and eventually learned that the only viable approach to getting a good finish on the concrete floors would be grind down the existing surface. Then, we would have to re-stain the concrete with an acetone mixture that would actually penetrate the surface and stain the top 1/8" of concrete. 

The process included grinding down the existing concrete with a 4 grit, 8 grit, 16 grit, 32 grit, 64 grit, all the way to an 800 grit, to give it a polished finish. The stain/acetone mixture was sprayed onto the floor into the final passes. This concrete staining process is referred to as acid-etching. Lastly, a very thin protective was layer was applied. 

To prep for this job, we had to move everything off the ground floor of the ADU. Then, we took off on a road trip for the long weekend, and let professional concrete contractors work their magic. A big part of their job was taping off the entire first floor so that the concrete dust wouldn't cover everything. They were extremely thorough, nonetheless, concrete dust still managed to seep through and coat some of the walls. 

Here are pictures of the process. They spent two long days re-doing the 500 sq ft concrete floor. When they were finished, the floors looked awesome, as shown below. Unlike the paint-like stain process I did initially 2.5 years ago, this new stain should remain looking glossy and rich for years and years to come. 

This job cost $2,500. It wasn't cheap. I asked the contractor how much this job would have cost if I had hired him outright at the beginning. He said it would have cost the same amount, which surprised me. So, in the end, my initial stain job wasn't a mistake that ended up costing me more money. Rather, it simply required some additional work to move everything out of the house for the weekend. 

In hindsight, I would have sought and asked for a concrete foundation company that would have been willing and able to do all of the concrete work, down to the polished finish, and sought input on how best to get to the final glossy look that I was seeking initially. This would have allowed me to avoid the annoyance of refinishing the concrete floors. Like many building trades, concrete work has a lot of specialized processes, and I have found that having specialists scope out, advise, and in this case, execute the project, was critical to getting a final product that met my expectations. 

Thursday, March 21, 2013

Energy Use Over the Last Year In the ADU

In earlier posts, I shared how living in smaller spaces reduces per capita energy consumption, which was part of my motivation for living more compactly. Furthermore, after constructing an energy efficient ADU, Energy Trust of Oregon even gave me a $1,750 rebate for meeting Northwest ENERGY STAR standards and achieving a modeled Energy Performance Score of 35. 

Now that I've lived in the ADU for over a year, I wanted to share the actual energy bills, and compare them to the energy bills of the main house. Comparing the utility bills of the two dwellings will allow me to draw a few conclusions regarding the nuanced personal energy consumption virtues of living more compactly.

Both homes are heated by natural gas. The ADU is heated via a tankless water heater and in floor radiant hydronic heat. The main house, built in 1906 and recently weatherized, is heated through a conventional forced air heating system.

Below are the natural gas bills for the ADU and the main house, respectively. The ADU consumed 277.5 therms, and the main house consumed 930.4 therms. A "therm" is a unit of heat equal to 100,000 British thermal units.
The total therms used in the last year in the ADU
The total therms used in the last year in the main house
At only 277 therms, the ADU used only 29% as much energy as was used by the main house for heating!

That's very cool, but that's not the real story. 

The real story must include the total energy use divided by the number of occupants. The designed occupancy level is calculated by taking the number of bedrooms in the house, and adding one additional occupant. This designed occupancy level assumes that two adults are living in a 'master bedroom' together.

The ADU is a one bedroom dwelling designed for two people. And, in fact, that is exactly what happened in the ADU;  two people lived in the ADU for the full year. 

The main house is a four bedroom house, with a designed occupancy level of five people. However, in reality, the actual occupancy rates of the main house were lower than the designed occupancy level; the main house maintained an average of three occupants throughout the year. 

Interestingly, census data shows that the average national occupancy rate for homes larger than mine at 1,700 sq ft, is surprisingly low. The average occupancy rate for homes of 2,500 sq ft is actually only 2.59 occupants.

So, let's look at the therms used per capita for both the designed occupancy and the actual occupancy.

If the main house were occupied at the design occupancy rate, each ADU occupant would have used 75% as much energy as the average resident in the main house. Living in the Northwest ENERGY STAR certified ADU would have been 25% more energy efficient than living in the main house.

But, in reality, with only three occupants in the main house, the actual therms used per capita for heating and cooling in the ADU was still 138.75, but the actual therms used in the main house was 310.13. This means that by residing in the ADU, I used only 44% the amount of energy that the average occupant used in the main house. Living in the ADU has been, in reality, 56% more energy efficient than living in the main house.

These are significant data points. Here are the stories that these data points tell us:

#1) Building the new structure to Northwest ENERGY STAR standards resulted in building a very efficient building envelope and in choosing to use efficient heating systems.

#2) By living at the designed occupancy in the ADU, my partner and I each lived more energy efficiently. Building a smallish dwelling alone did not make the dwelling energy efficient. It was dwelling in a smaller footprint per capita that had the most substantial energy efficiency impact.

Said another way, if I lived alone in the ADU, and the main house was fully occupied at the design occupancy of five people, I would have actually used 50% more energy than the average resident in the main house.

#3) In smaller dwelling spaces like my 800 sq ft ADU, I was prone to live at the designed occupancy level of two. Conversely and representatively, the main house was prone not to be fully occupied (according to US Census data).

These last two points are a thinking person's fodder for a housing revolution.


I'm also including my electrical bills from the last year for reference. Since neither the ADU nor the main house used electricity as the primary heat source (where the bulk of a home's energy is used), these data points are less relevant.

That said, indeed, the ADU was more efficient than the main house in terms of electric power consumption due to the types of appliances and light fixtures that were installed. But, one will still draw a similar conclusions that I have drawn above regarding designed and actual occupancy

Under actual occupancy rates, living in the ADU used 30% less electricity per capita than living in the main house.        Under designed occupancy rates, living in the ADU would've used 18% more electricity per capita than in the main house.
In terms of electricity, the ADU was more efficient under actual occupancy rates. But, if the main house was occupied by five people, the electricity use per capita in the main house would have actually been lower than in the ADU.

Electricity used in the last year in the ADU

Electricity used in the last year in the main house

Note the July spike in electricity use in the main house and the lack of a spike in July for the ADU.

The main house is set in direct sun, has R12 wall insulation, and has an AC unit.

The ADU is kept cool through deciduous tree shading, R33 wall insulation, and a ceiling fan. :)

Thursday, February 21, 2013

One Data Point for the Property Tax Impact of an ADU

My property tax appeal was successful. My property taxes were officially lowered from $4,021.75 to $3,154.21 for 2013.

Adjusted tax statement from Multnomah County

This is still a big increase from my 2012 tax burden of $1,599.43, but it's a fair increase based on Multnomah's tax code. 

Property taxes before and after the ADU was added to the lot

For others who are considering the fiscal impacts of an ADU to their current property tax, the important numbers to note in terms of possible tax increases are that my ADU cost  ~$100K to build, it was valued at ~$90K by the county, and that this additional 'real market value improvement' increased my taxes by ~$1,500.

A property tax increase post-ADU, should be proportional to the contributory value of the improvements. Using my increased tax figures as a baseline, and assuming that I understand Multnomah tax code correctly, if an ADU adds between $50K-$150K of contributory 'real market value' to a property, the property taxes would go up proportionally from ~$850-$2,550/year.
To figure out how an ADU may impact your property tax if you're in Multnomah County, simply multiply the assumed increase in assessed property value by 0.017. That will tell you approximately how much your taxes will increase after you've added an ADU to the property. 

And take my formula with a grain a salt be cause I am just a guy with extra time on his hands and MS Excel.

Wednesday, January 9, 2013

Successful Appeal of the County's Initial Assessment of the Contributory Value of the ADU

In my last post, I described how the county attributed approximately $142K of contributory value from the new ADU. This translated to a HUGE annual property tax hike; from $1,599 to $4,021.

What I didn't describe in that post was that upon receiving the County letter in the mail, I immediately gathered together evidence that my ADU was actually worth far less (it is worth ~$100K) and wrote an appeal to the County Board of Property Tax Appeals. I submitted the appeal package in full the following day at the County tax office.

When I spoke with the kind lady behind the County desk, she informed me that the assessor, who I'd allowed into the property, had noted in his records that I had added a 1,350 sq ft ADU. Given that the City of Portland's regulations only allow ADUs of up to 800 sq ft, I had evidence to prove that his spatial calculations were necessarily off target by ~68%. I also learned that the County assessor likely applied a simple numeric formula to this miscalculated sq footage to come up with the obscenely high contributory value for the ADU of $142K (eg. 1,350 sq ft x $105 sq ft= $142K).

A couple months after submitting my appeal paperwork, a 2nd assessor contacted me and visited the property. When he arrived, he explained that he had read through my appeal documentation, which had included a full copy of a 3rd party appraisal. Upon visiting and measuring the property, he concurred that the initial assessment of the size of the ADU seemed incorrect and he shared that he'd never seen an ADU add more than $100K to the value of a property.

It's worth noting that the initial County assessment apparently included the ADU attic space in his sq footage calculations, whereas the City did not count the attic as living space. The 2nd assessor agreed that the attic should not be counted in the sq footage calculations.

It's also worth noting that the County assessment includes the total building footprint (i.e. the exterior walls) in the sq footage calculation, whereas the City only counts interior space (i.e. drywall to drywall). The County includes exterior dimensions because assessors must be able to assess the building from the outside since homeowners aren't required to allow assessors entry into the home and many homeowners deny entry. These two variables help explain why the first sq ft assessment was so off target. However, I never would have known about this sq footage miscalculation had the kind lady behind the desk not mentioned it; this 1,350 sq ft figure wasn't in the initial letter they sent.

Today, I received an updated property tax assessment in the mail, which I am happy to report, accurately attributes ~$90K of contributory value from the ADU to the property, $53K less than their initial assessment!

The "From" column relates the 2013 figures from the "This Year" column in the first image at the top of this post.

The "To" column shows the new figures according the 2nd assessment, which will override the initial assessment.

Whereas the initial assessment indicates the market values of the structures (main home and ADU) at $320,600, the new assessment has the market values of the structures at $267,600. The new assessment values the ADU at ~$90K, which tracks perfectly with my cost of construction and my private appraisal.

I don't yet have a newly updated tax bill, so I don't know what my actual annual taxes will be. But, I estimate that the updated tax on the property will probably come be about $3,100/year. Once I receive the final property tax bill, I'll post it for all to see.

If my estimate is correct, this will be $1K less per year than the initial County tax assessment. It is still a $1,500/year increase to the property tax, a two-fold increase from what my taxes had been before I built the ADU. But, based on the County tax regulations, this new property tax burden seems fair and reasonable.

Wednesday, October 24, 2012

Property Taxes for the ADU

Many people have inquired about how the ADU effected my county property tax. Up till now, I had no idea how the addition would impact it. Even the county's appraiser who inspected the ADU last spring couldn't give me any sense about the impacts of the ADU on my overall taxes.

I finally have an answer: It is raising my taxes a lot! In my case, it's raising my property taxes by $2,422.32. Said another way, it's more than doubling my property taxes (a 2.5X increase to be exact).

Whereas before, the total value of my property's structures (just the main house) previously were $177K; now, with the ADU added to the property, the county is assessing my property's two structures (the main house and the ADU) at $320K. I assume of course that the vast majority of that $142K increase in the county's structural valuation is attributable to the addition of the new ADU.

This doesn't reconcile with what a private appraiser found as the worth of the property with the ADU addition. In fact, this county valuation is over 50% higher than what the appraisal said.

This property tax anecdote should be considered with a grain of salt, as each property has unique attributes and history that would effect how an addition would increase the tax burden. With ADUs being relatively rare, this story can serve as one reliable data point. However, there are many factors than play into property taxes, so I won't speculate as to how this data point compares with other properties that have ADUs.

And, it's important to note that this relatively huge new property tax burden does not hold a candle to the very tangible financial benefits provided monthly or annually by having the ADU.

If ADU Financing is of interest to you, I encourage you to attend the Build Small, Live Large Summit this Friday, October, 26th. I'll be speaking on a panel entitled Financing the Accessory Dwelling Unit.

Wednesday, September 19, 2012

Finishing The Stairs

(Editor's note: I've authored a related post called Staircases in ADUs on

I'm authoring this post a year after we completed building and moving into the ADU. Dare I say, this is the last substantial construction project for my ADU.

Over the last year, Deb and I have slowly tackled various projects which I've described previous blog posts (the artistic sound barrier, the artistic handrail, landscaping and more). But, as any homeowner knows, it seems as though the work is never done. Once we moved in, it was easy to let the final stair riser tiling project slip off our immediate calendar.

With the ADU being on the upcoming Build It Green tour on Saturday, September 22nd, we motivated ourselves to put the finishing touch on the stair case (the end of this post includes several ADU related announcements which may be of interest to readers).

The finished stair tile risers.

From the outset, the stairs have posed an intriguing design problem. Complying with stair codes is sometime difficult in small and stout houses, such as ADUs. Portland's code requires that an ADU roof must be no taller than 18ft at its mid-point, so fitting a stair with adequate head room (6' 8") on the top stair landing, can prove to be a tricky design challenge.

There are two common design solutions. One can position a straight, simple staircase in the middle of the house, which can interfere with the spatial layout of the main floor. Or, one can position the stairs along the side of the house, and turn the top of stairs toward the center of the house before you reach the 2nd floor landing to avoid hitting your head on the ceiling.

My architect worked through many sketches before finally figuring out a functional, compliant, attractive, and space-efficient staircase design, consisting entirely of "winders". The final stair design consisted of 14 "winders": stairs which are not rectilinear, but have an angled curve as they rise upwards.

This is the architectural drawing of the winding stairs from above

The master framer would built this stairs claimed to have build over 2,000 stair cases and said that he had never built a staircase in which every step was a winder. It was a wonderous feat to watch how he constructed the framing for them.  

In addition to the unique bend of the staircase, we added a few other design elements to the staircase. When staining the stairs, we stained the nose of each tread a lighter color so that it would be easier to see each tread in lower light. Additionally, we added an LED rope light under the nose of the treads, to create an attractive perimeter/safety light solution for climbing the stairs in low light.

The LED rope lighting under each tread accents the stair below it. The nose of each tread is stained a light color in contrast to the rest of the tread, which makes each tread "pop" nicely in any kind of light, such as the low light as shown above.

Then, we added the amazing salvaged steel handrail, part of which is shown below.

Last but not least, we finished the stair risers with tiles this week. We acquired these tiles in New Mexico last year, knowing that we wanted to eventually finish the stair risers with Talavera tile. Here are some pictures of the process and finished product.

Here's a video of the finished product.

Some other ADU announcements:
  • The next ADU Class for Homeowners will be on Saturday, November 5th. This course is filling up so I'll likely offer another full day class shortly thereafter.
  • For the first time, I'm also able to offer CE credits to Oregon's real estate professionals who attend this class, thanks to the Earth Advantage Institute. The class will equip them with substantial knowledge about ADUs, enabling them to help more of residential clients identify suitable properties for ADUs, and provide information on how a residential client can proceed through the ADU financing,designing, and building process.  Please tell Portland realtor acquaintances about the class.
  • There will be a one day ADU-focused conference in Portland, Oregon, on Friday, October 26th, held in conjunction with the Portland EcoDistricts conference. I'll be helping lead one session on ADU financing, and there will many fantastic sessions there. 
  • Lastly, my ADU was featured in a great blog called Small House Bliss which I'd commend to readers who are seeking inspiration on modern, small house design. 

Tuesday, June 26, 2012

An Artistic Sound Barrier

Residents and architects know the importance of visual privacy, but the psychological value of sound privacy is often forgotten in building design.

In attached dwellings, sound transfers between adjacent structures. Hotel guests have experienced the lack of adequate sound privacy between room walls, and apartment building residents may have been subject to the sound of their upstairs neighbors' footsteps. Indeed, sound privacy is an attribute that helps makes detached ADUs preferable to attached units.

In contrast, detached ADUs can be quiet urban retreats due to not sharing structural walls with another unit. My ADU has thick, insulated walls, which deaden the sound of the busy city that surrounds it. But, inside the exterior walls, sound travels freely.

A collage of images of the finished artistic sound barrier
Why is Sound Privacy Relevant to ADUs?

Good small house design attempts to make a place feel large despite the smaller size. This is accomplished by designing a relatively open floor plan. This means conjoining the living room, dining room and kitchen, into a "great room". Vertically, ceilings are lofted, and ideally, parts of the 2nd floor ceiling should also be visible directly from the ground level to create an illusion of grandeur.

Clean indoor air quality design utilizes hard surfaces instead of rugs and carpets, which tend to trap atmospheric deposition and dust mites (and their excrement), collecting and exporting particulate matter into the ambient indoor air that we later breathe.

Deliberately utilizing both of these design techniques, our ADU had both an open floor plan and hard surfaces (concrete and hardwood floors). Unfortunately, when coupled, the byproduct of these two design techniques was noise reverberation from one room to the others. Sound tended to reverberate off of the hard surfaces and it traveled easily from one open room of the house to another.

Prior to building, I wasn't sure how the sound would behave in the ADU, but while living in the ADU over the last ten months, I have experienced it first hand. Noise transfer has actually caused me to loose sleep this year- no laughing matter for a lover of sleep.

For example, if my partner woke up and quietly made coffee while I was sleeping, it was audible enough that it woke me up. If I watched a movie downstairs at night, it was very easy for my partner to hear it from the bedroom. When my dog was lying in the living room scratching behind her ears, it jingled her metal name tag and it was like she was shaking a tambourine.

In the design phase, we'd considered the possible audio impacts of the vertically open floor plan, but thought that it would be wise to actually live in the ADU before making a decision about whether, and how, to enclose the bedroom walls to prevent the transfer of sound from the downstairs to the bedroom.

Arriving at the Sound Barrier Design Solution

My partner and I loved the look of the opening to the bedroom, but it wasn't worth continuing to lose sleep over it.  Our design goal was to develop an artistic sound barrier that would still let light pass through the house, but that would cut down the amount of reverberating noise into the 2nd floor bedroom. I worked with a Portland craftsman and friend, Eric Bohne, to develop, design, and execute a functional design to visually fit alongside the stunning metal handrail and the alternating tread staircase to the attic.

After many iterations of design ideas (which I won't bother to describe, but you're welcome to see in the photo and video collection below), we settled upon a design that would accomplish the desired goals. We decided to use stained glass as the medium, structurally connect the pieces with a steel frame. This captioned photo and video collection shows the chronological steps of the design, building, and installation process. There are ~65 pictures and ~5 videos in this collection.

The finished piece would look like a sunburst of textured, rich colors from a bejeweled sun. Beyond the window centerpiece, stained glass rays would graduate from semi-opaque to semi-translucent toward the outer frame. Here is a photo of the operable window centerpiece:

A beveled gem, enshrouded by a colorful burst of clear bevels and richly toned stained glass, composes the focal center of the metal and stained glass sunburst sound barrier.
Here are images of the artistic sight lines created by the finished sound barrier in varying lighting conditions.

To accomplish this design, Eric built a precisely-measured frame from steel tubing. I hired a talented glass worker, David Schlicker to do the complex stained glass elements. Together, Eric and David created a piece that accomplished the design goals- it deadened the sound transfer but still artfully allowed light through, creating an artistic piece that augmented the space, rather than detracting from it.

Before and after images of the sound barrier. These images are taken from the kitchen below.

Before and after images of the sound barrier. These images are taken from the bedroom side.

This five-minute video shows the stained glass piece in completed form, and details the architectural and design aspects of the stained glass and the layered construction method that was used to minimize sound transfer.

In this five-minute video, David goes into detail about the types of glass used in the stained glass piece. He explains each element of the production of the window centerpiece.


The whole project took two months to build. The metal frame took about a week and the glass took about six weeks. Both the metal and the glass were built off-site in the respective studios. Installation went flawlessly, and only took a few hours.

While on the topic of artistic sound barriers, I recently built a hatch door for the attic. This gives both visual and sound privacy for guests who sleep there occasionally. Here is a two-minute video that shows what the hatch door looks like and how it works. It's built from a salvaged wooden door that match the other doors in the ADU.

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