The Outside Layer

People wear different clothing depending on where they are and what they are doing.  What you see on them, whether it be a banker in New York or mountain climber on Everest or a surfer in Hawaii, reflects both the function they’re engaged in as well as their personal taste.  The mountain climber will likely wear several different layers such as the base layer to wick moisture away from their body, some middle insulting layers to keep warm and some outer layer that serves as wind and moisture barrier to stay dry.  All of them expressed in whatever color, style, and material to be fashionable.  You can think of the house in the same way where different layers serve different purpose and the styling and color reflects the owners’ taste.

In this post we’ll cover the exterior look of Midori Haus.  We’ll continue the story from the exterior mineral wool insulation.  You may recall from the insulation post of this blog that 3.25 inches of rigid mineral wool insulation (Roxul Toprock DD) was nailed on to the outer surface of OSB sheathing.  Over that Tyvek Home Wrap was applied.  This is the layer that protects the home from wind and rain that could penetrate the exterior siding. 

Tyvek Home Wrap over mineral wool insulation

Then furring strips were nailed over the Tyvek Home Wrap. The furring strips are used to fasten the sidings.  If you would like to see example of furring spacing, number of screws and other details for attaching furring strips have a look at this article from Green Building Advisor.com.

Furring strips

Screws used to attach furring strips

Extra care was taken around the windows to prevent water damage.  For details on why windows flashing are important and how this is done, see article in Fine Home Building.  (Note: this article doesn’t describe what was done on our house)

When we were asked about the details of trim around the windows and doors Kurt and I looked at each other and said, “Let’s look at examples in the neighborhood and agree on what we like.”  So we took a walk down our street as well as some of our favorite local streets with Arts and Crafts style homes.  We showed David, the lead carpenter, the style of trim we liked and he mocked up a window trim.  This was really helpful in getting the decorative detail in a way that felt subtle and classic.

Is the flared skirt look on the side of the building called “Battering” or “Flared Siding”?  At one point someone told us that it was called battering but I can’t seem to locate a source that calls this battering. Anyway, the original house did not have the cute flared skirt but Kurt really liked the look of having this flared siding to give a a bit more of Arts and Crafts look.  So the crew of Santa Cruz Green Builders cut many pieces of wood to shape the flared skirt look for the house, including the trim of the door.

Cement fiberboard siding product called, HardiePlank, was used as the lap siding material for the body of the house. We selected this material because it is durable (resists rot, won’t burn, termites won’t eat it) and the company has a sustainable manufacturing practice.  While we could have chosen different types of surface that simulates different wood grains, we decide to go with the smooth surface.  For the top area above the belly band we used the Hardie Shingle product.  

Hardie Plank Lap Siding

Installing Hardie Plank Lap Siding

Hardie Plank Lap Siding with the flared skirt effect

Hardie Shingle siding

Installing Hardie Shingles

One of the outcomes we want for our house is the aesthetics and curb appeal of the 1920’s Arts and Crafts look of a California Bungalow.  We chose to reflect these in the grill pattern on the windows, trim around the windows, lap siding, front porch, the hint of flared skirt effect on the siding, and keeping the original footprint of the house.  A slight deviation from the Arts and Crafts aesthetic is the decks outside of the kitchen and bedrooms but this adds the indoor-outdoor connection we wanted for our lifestyle.  For reading on bungalows, I invite you to read The Bungalow: A Short History on the Arts and Crafts Home page.

Walls and Ceiling

We’ve removed asbestos and lead based paint in the original house.  So we should have safe and healthy indoor air in the house, right?  Not if you don’t pay attention to the material you introduce into the house.  Earlier this year we read a book by Bill Bryson titled, At Home: A Short History of Private Life.  A curious and well-researched book containing facts about homes in England and US, there were many astonishing examples of the rooms, materials used for homes and how people lived.  In Chapter 14 he mentions ways in which how our houses can hurt us.  One example is wallpaper.  After 1775 a popular shade of green was made by soaking the wallpaper in a compound containing copper arsenite invented by a Swedish chemist, Karl Scheele, and the color was known as Scheele’s green.  Use of wallpaper increased after the wallpaper tax was lifted in 1830 in England and by the late 19th century 80% of English wallpapers contained arsenic.  Today most of us know that arsenic is toxic.  But back then they didn’t and the rich green color containing arsenic was used in candles, clothing and even food coloring.

A more recent example of walls in your home causing harm is the reactive sulfur gasses coming out of certain drywalls manufactured in China.  According to CDC report the people who lived in US homes that were built between 2001 and 2008 containing imported drywalls experienced headaches, eye irritation, difficulty breathing and other health problems.  The Chinesedrywall website appear to have collection of information related to this issue.  By the way, the term drywall, sheetrock and gypsum board appear to be used interchangeably.  For a quick overview of the history and manufacture of drywall see this video.

We know that people made decisions based on information available to them at that time.  Some of these, like asbestos, has beneficial qualities like fire-resistance and sound absorption that made it attractive to use in various building materials at one time.  It’s only later when the side effects of these materials that caused serious illness, such as lung cancer from inhaling asbestos fibers, that made these materials fall out of favor.  So, in 2012, we’ve chosen materials based on what we know today to be benign and promote good air quality.

Our house was built in 1922 so the original walls and ceiling were made of lath and plaster.  Here are some photos of the original wall taken during deconstruction.

Plaster above the door chipped away to reveal the lath underneath

“Lath” is the narrow wood strips nailed horizontally across  wall studs.

Plaster oozing through the lath holds it in place

Below are the “after” pictures of the new walls.

We chose to have fiberglass batts installed in the interior wall cavities between rooms.  The purpose for this is not for thermal insulation but for sound attenuation.  We noticed that the hardwood floor over a crawlspace seem to carry the sound throughout the house, perhaps similar to how a sound reverberates within a guitar. We were told that another way to dampen the sound is to use different thicknesses in the drywall, for example using 5/8″ and 1/2″ on either side of the wall studs.  We didn’t do that.  Hopefully the fiberglass batts will dampen the sound of me playing my flute to prevent annoyance to others in the house.

AirRenew drywall from CertainTeed was selected.  This drywall product promotes indoor air quality in two ways — 1) Traps volatile organic compounds (VOCs) such as formaldehyde in the air and makes it inert and traps it inside the drywall; 2) Resistent to mold and mildew.  You can watch a short video of this here.

Ceiling and walls installed using AirRenew.

Lydia Corser from GreenSpace advised us to be selective of the plaster used to texture the drywall.  Her store, located next to Habitat’s ReStore on the west side of Santa Cruz, is a great place to get get paint, flooring, countertops and various interior materials for your home.

We selected M-100 hypo-allergenic powder compound from Murco to be used to texture the wall.  This product is formulated with no VOC’s, preservatives, mildewcides or fungicides.

The compound is mixed with water.  I was told that this product is a little bit harder to mix than the usual texturing material.

Though harder to mix application is the same effort.