Building a new house in Palo Alto

Building a new house in Palo Alto

Sunday, March 18, 2012

Mythbusters edition: Single-story vs two-story homes

When we started planning our house we never even considered a single-story home. We had long been told that in order to maximize square footage, you had to build up.  This seems to be conventional wisdom amongst real estate agents and old-timers in Palo Alto because we heard this over and over again and never thought to question it.

Fitting into the neighborhood is challenging.
Last month while trolling open houses, we fell in love with a beautiful single-story house for sale in Barron Park.  Coincidentally, it was around the same time we found out the Palo Alto Planning Department rejected our two-story home plans for "failing to meet the Neighborhood Compatibility for Height, Mass, and Scale guidelines."  The city planners sent us back 13 pages of comments and changes to make us more compatible with the neighborhood.  Their main objection was the height of our house--25 feet.  While the maximum allowable height in Palo Alto is 30 feet they wanted us to lower it to 24 feet to be more in line with our single-story neighbors.

Since we had to go back to the drawing board anyway, we decided to consider a single-story house.  At that point I started researching the pros and cons.  Much to my surprise, I found that you do not have to build a two-story house to maximize square footage in Palo Alto.

Reasons to build a single story house in Palo Alto

1.  You get *more* house with a single story
The Palo Alto's Zoning Ordinance Technical Manual located on the city's website states that the maximum allowable lot coverage is 35% of the lot size.  It goes on to say:  Allowable gross floor area is expressed by a ratio—the sum of 45% of the first 5,000 sf of the lot area plus 30% of any portion of lot area in excess of 5,000 sf.  Both taken together, this is consistent with what everyone was telling us about why you have to build up in order to get the maximum allowable floor area ratio.  When we started digging around more, we found this buried in section 18.12.040 of the Palo Alto Municipal Code:  Maximum site coverage for single story development is equivalent to maximum allowable floor area ratio.  For multiple story development, maximum site coverage is 35% of lot.

The code suggests that the 35% lot coverage limit only applies to two story homes.  Given the two conflicting documents I went to the city planning department to find out which document was correct.  I checked with multiple people and they all responded the latter--no penalty for a single-story.  I doubled checked and tripled checked, asking the question in as many different ways as I could until their eyes started rolling.   The myth that you have to "build up to max out" has been busted!  Not only that, by not building up, we would gain back 91 square feet because we wouldn't need to waste square footage on the stairs.

[July 2012 Update: If you'd like to see what I think is a perfect one story layout, check out this recent post: James Witt's Palo Alto dream house is for sale.]

 Barron Park ceiling envy 
2.  Ceilings can be up to 16' high
One of the things we loved about the Barron Park house was its soaring ceilings.  Our original two-story plans had 9.5 ft ceilings on the first floor and 9 ft ceilings on the second floor.  The thought of lowering our house another foot was really grating on us.  With a single-story home, the ceilings can be up to 16 ft high.  Because you don't have a second story above it, you can vary the ceiling styles from room to room and you can install skylights wherever you want.  The result is an open feel with lots of natural light.  We loved the high vaulted ceilings in the Barron Park's great room, the sloped ceilings in the master and the ginormous glass patio doors.  The house made you feel like you were walking through an art museum.  Another benefit of a single-story home is that with 16' to play with you can put in plenty of attic space.  The only penalty for building ceilings higher than 16' is that the area above it gets counted twice when calculating total square footage.

3.  Rear set back exceptions 
According to the Palo Alto Municipal Code, homes must conform to the 20 foot front and rear setbacks.  However, the city planner we're working with told me that they will make an exception for the rear setback of a single-story home.  She said that they will allow you to have a 6-foot rear setback for part of the house as long as the encroaching section is less than half the width of the lot.  I couldn't find this documented in any of the codes, so double-check this with your planner if you're thinking of taking advantage of this exception.  In certain cases (i.e. sustainability reasons), the planners may grant this exception for the first floor of a two-story home, as well.

4.  No public comment period
Single-story home plans do not have a public comment period.  Unlike two-story construction, neighbors cannot demand a public hearing and fight building plans they object to.  We didn't have any complaints about our plans from our immediate neighbors.  A distant neighbor wrote in saying he opposed all two-story construction.  The city planner politely informed him that two-story homes are permitted in our neighborhood.

5.  Quicker & less elaborate review process
All two-story construction in Palo Alto requires an Individual Review process.  The process looks at issues such as neighborhood compatibility, privacy and sunlight.  Neighbors can oppose your plans and request a public hearing, as well as appeal decisions made by the city.  The guidelines for this review process can be subjective depending on the whims of the planners assigned to your project.  This can be unpredictable and take months depending on how persnickety your planners and neighbors are.  In addition, there are application fees for this review.  Ours totaled $3907, not including the cost of having our architect negotiate the changes.  With single-story construction you get to skip this step.   There are no judgey reviews to determine whether your house conforms to the neighborhood standards.  As long as you follow the building codes, you can design whatever look you want and it'll be approved.  Had we opted for a single story home we could've saved at least 2.5 months and probably over $6000 in fees and changes.

Every city is different so before you decide what to build, talk to your city's planners to find out if there are significant incentives to go one way or the other.  In addition to these considerations, there are numerous pros and cons of single-story vs two-story living which we debated while trying to make our decision.

Single-story benefits
+ more options for ceiling heights & skylights
+ more possibilities for attic space
+ more living space since you don't need to spend square footage on staircase
+ safer for small children & easier for older/mobility challenged individuals/dogs
+ easier to evacuate in case of a fire
+ no noise from stairs & second story traffic
+ less bathrooms needed since all are on same floor
+ can combine mud room with laundry room

Two-story benefits
+ more expansive views from second-story
+ more yard area due to smaller footprint (in our case: 981 sq ft more yard)
+ distinct separation of public and private spaces
+ smaller foundation and roof area
+ upstairs bedrooms have more privacy
+ upstairs windows are safe to leave open
+ less roof to maintain, less distance for pipes and wires to travel
+ good exercise running up and down stairs everyday!

Cost of single-story vs two-story
While researching cost of construction, I found conflicting opinions.  Most of what I found online claims that it's cheaper to build up than out.  Online pundits argue that a two-story house is cheaper to build because it requires less foundation, rafters and roofing materials.  When I asked our architect, she said that in her experience, single-story homes are less expensive to build.  I also asked our general contractor for a guestimate and here's what he had to say:
If it's remodeling an existing home, then adding a single story addition is usually less expensive than adding a second story.  This is because adding a second story usually requires adding piers/foundation work under the existing structure to support the second story.  This can result in flooring and other finished surfaces getting opened up to make access to do the structural work, which is an added expense to repair or replace these finishes... 
With a new single-story you might end up spending more on foundation and roofing cost, but depending how it's designed, the production rate of construction will be faster.  A second-story might have more construction challenges which will result in a slower production rate, and perhaps deeper foundation and added cost of stairs.  You might need scaffolding or special equipment to deal with the height issues, but overall, I'd have to say that new construction single-story and second-story homes are comparable in price provided they have the same quality finishes. 
Since there wasn't an obvious difference in cost between a one-story and two-story house, we decided to look at resale value instead. [Update 8/2012: I recently asked my builder friend, James Witt if it was cheaper to build a single story vs a two story house and he said that the cost differential is close enough that it shouldn't drive your design decision.]

Building the American dream

When I asked our real estate agent for her recommendation she voted for the two-story home.  Her feeling is that people think that two-story homes are grander and worth more.  I tried to look for data to support higher resale value for two-story homes but couldn't find anything providing a direct comparison of dollar per square foot value.  In the absence of hard data, I did the next best thing...I had my research team turn to Hollywood in order to verify these claims.  Here's what I found:

The Cleaver's                                  The Brady's                                              The Cosby's          

The Dunphy's
The Simpson's

Hollywood's portrayal of the all-American family has declared: Staircases = Family.  Surely, decades of American television cannot be wrong.  For generations, the portrait of a modern family home has centered around the staircase.  It's the quintessential image of the American dream.

Hollywood observations aside, my informal polling also suggested that families with younger children prefer the convenience of a single-story house, whereas families with older children value the separation of two-story homes.  After much consideration, we ultimately decided to stick with our original two-story floor plans.  Given the beautiful trees that surround the neighborhood, we decided we'd greatly value the serenity of the second-story views.  We also concluded that buyers in our neighborhood are more likely to be families with older children since our house is located next to one of the top high schools in the state.        

This week we are resubmitting our two-story Individual Review plans to the city of Palo Alto.  We've lopped off a foot from the height of the house and incorporated other requested changes to the design.  We are now praying to the planning gods of leniency to bless our little Craftsman like the orangesicle dream house in College Terrace.  Just sayin'...

This charmer must have Jedi mind-tricked the city planners.


  1. How did I miss this post until now? The first pic is hilare! The "TV family through the ages" photo series, ending with the Dunphys and the Simpsons is proof enough, really, that two story is the way to go. That is like, so scientific I can't believe it doesn't have some fancy theorem name. But I have to say, one stories are pretty amazing. Como se dice Palm Springs super modern glass walled ranch house? Your pros and cons are spot on.

  2. Orangesicle!

    Great analysis, Kay. My "commune" pals who live in Evergreen Park got to your same conclusions for their home design; backing off on 2 stories and going with 1 story that is raised -- sitting on top of a ginormus basement which gets lots of natural light via windows about 3 feet high all along the top of the walls of the basement. So true about ceiling heights and natural light!

    Thanks for the great blog!!

    1. Glad to have you as a reader, Slackerboy! One-story living is definitely underrated. And having height and light for a basement is another advantage I didn't think of.

  3. Thanks for the a very informative blog, Kay! Regarding rear setback exceptions, it is mentioned in the Palo Alto's Zoning Ordinance Technical Manual you referenced (pg. 24)