Update – framing complete!

Sorry it’s been a while since the last post.  We’ve been very busy with five other homes and several critical home repair projects.

The framing of the ZEHR home is complete!  The rough plumbing is done, the rough electrical is about 80% finished, and the mechanical contractor began rough-in last week, so things are moving along nicely.  As you can see from the photo below, we are waiting to pour the front porch until the water and sewer are connected, so the roof is temporarily supported.  All of the windows are in and house wrap installed.  We’ll discuss windows and flashings in another post.  The roofers will begin in a few days to get the shingles installed.  We’ve pulled off for now to work on other projects, but will return soon to insulate and hopefully begin siding.

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Focus Kalamazoo

We need to send out a huge “thank you” to the local volunteer group, Focus Kalamazoo.  The small, grass-roots organization was founded by Tinashe Chaponda and Alex Nassaney, two students at Western Michigan University.  They have spent the past few years recruiting and coordinating volunteers for local non-profits, including Habitat, and have been a vital part of our work.

A few months ago, they applied for a grant on our behalf from the local Turn 2 foundation (a local non-profit started and sponsored by Derek Jeter, the New York Yankee’s phenom), and was awarded the grant — for $10,000 — to be used to help fund the construction of the Zero Energy Ready Home!  We cannot thank them (and the Turn 2 foundation) enough for their hard work and generosity on our behalf.

To learn more about both organizations, click the links below:

www.focuskalamazoo.org

www.turn2foundation.org

Framing

We began framing the home on June 2, 2015 as the project site for our 2015 Women Build.  This is a one or two week build project we’ve done every year since 2009 where we invite women from the community to come out and volunteer on a Habitat job site.  It is our goal to encourage women to join the Habitat movement and dispel the myth that our construction sites are a “men’s only” zone, which is far from true.  We were lucky to have had 15-25 people on site for two four-day weeks, well over half of them being women.  The volunteers did an amazing job, and by the end of the second week had the roof trusses on, the walls pretty much enclosed, and were beginning to lay down the roof decking.

On this home we chose to use an unconventional framing style on the walls, where we used 2×6 top and bottom plates and 2×4 studs, with the studs in a staggered pattern.  The result is that nowhere in the home (except at windows and doors) do the studs run from the inside of the wall to the outside.  Since wood is not a very good insulator, this “thermal break” in the framing drastically reduces heat loss through the walls, saving energy.  You can see the staggered pattern of the studs in the photo below:

IMG_8992We also used a framing method that allows wall insulation to carry all the way around the outside corners of the home’s framing.  Since the corners of a home are typically a major area of heat loss, by again providing a thermal break, we cut down significantly on the amount of heat leaving the home.  We will use metal clips to install the drywall in the corner instead of a wood stud.  The photo below shows the corner framing:

IMG_9008The exterior walls were also built using what are called “advanced” framing methods.  This means that any lumber that is not essential for the structure of the home is simply not used.  Since fiberglass or cellulose insulation is far better at preventing heat loss through the wall than wood, anywhere you can remove wood and replace it with insulation will save energy.  The average home may have 25-30% of the wall space as framing, whereas our will only have 10-15%, allowing for much more insulation in the walls.  Another benefit of advanced framing methods is that the amount of wood used to build the home is reduced, conserving natural resources and reducing cost.  Here are the advanced framing techniques we used in the framing of these walls and photos below each:

1.  Single top plates instead of double that are typically used.  By aligning the roof trusses directly over each stud, a double top plate is not necessary for structural strength.

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2.  Studs placed on 24 inch centers instead of the usual 16 inches.

(notice the light blue line between the concrete floor slab and the foundation wall in this photo.  This is the layer of foam that isolates the floor from the ground)

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3.  Staggered-stud framing, using 2×6 plates and 2×4 studs.  In this case somewhat more lumber is used than a standard 2×6 wall, but the energy saving benefits are well worth the small additional cost.  And since 2×6’s are more expensive than 2×4’s, the added cost isn’t really all that much.

(Notice in this shot the foam being applied to the outside of the concrete foundation wall and slab to hold in heat for the shallow footing system.)

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4.  No wood headers above non-load bearing windows and doors.  If there is no weight above the opening, why put a large piece of lumber there to support it?

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5.  Where wood headers are required for support, we used single headers instead of double or triple that are often used.  They still meet or surpass code for support. The typical window header has an R-value (insulation value) of about R-6.  With the insulation we can add by reducing unnecessary lumber, ours will be R-22.  You can see in the second photo where we installed layers of Dow foam into the void behind the wood header for insulation.

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6. Single king/jack stud under load bearing headers.  We combined the typical king stud and jack stud that would support each end of a window header with a single stud.  We did this by notching the stud to let-in the header.  You can see in the photo above how the header runs past the king/jack stud on the right hand side of the framing for the window.  The lower portion of the notch is covered by blocking used for attaching siding later on.

7.  No trimmer studs, or “cripple” studs, as they are sometimes called, under window sill framing.  They are simply not needed.

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8. Outside corners framed with heat loss in mind.  We went an extra step beyond and framed open corners that can be fully insulated to stop heat loss.

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9. Raised-heel, or energy-heel trusses.  Much of the heat loss into an attic is at the tops of the outside walls, and this also contributes to snow melt on the roof and potential ice dams.  By raising the height of the trusses where they sit on the wall, the full depth of insulation in the attic can carry all the way over the outside walls, preventing heat loss.  On this project our trusses were ordered with 16 inch energy heels, which will allow for 16 inches of attic insulation over the outside walls.

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10. Continuous exterior wall sheathing.  Instead of applying a layer of plywood or oriented strand board (OSB) to the outside of the wall which has an R-value of R-0.5, we chose to apply a layer of 2 inch thick Dow foam, which has an R-value of R-10, or 20 times better than OSB. We used metal diagonal wind bracing to keep the walls rigid, since foam does not have the shear strength of plywood or OSB.

11. Ladder nailers for partition walls.  It used to be common to build U-shaped assemblies out of 2×4’s to catch an interior wall where it intersects an exterior wall.  This leaves a space where no insulation can be added, making cold spots in the wall.  We used 2×4’s in a ladder pattern to nail interior walls to, allowing for full continuous insulation behind.

(Notice the extra metal bracing on the interior walls for better strength against wind shear.  At this point the window openings had not been cut out of the foam.)

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Once all of the walls were framed, we installed the 2 inch Dow foam sheathing to the home to enclose the walls.  Heavy duty, zero-VOC (volatile organic compound) adhesive caulk made by ChemLink, a local manufacturer of eco-friendly products, was used to glue the foam to the faces of all of the studs, which gives the wall extra strength plus helps to seal the walls for less air leakage.  On top of the foam sheathing we will apply a layer of Dow Weathermate house wrap, which will form a weather-resistant barrier with which we can flash our windows and doors to seal out water.  With the advanced framing techniques, continuous foam sheathing, and well-sealed wall assembly, this home should perform extremely well in all seasons, maintaining a very comfortable indoor environment and saving money for the home owners.

Foundation

We are especially proud of the foundation we have built for the home.  We have used what is called a Frost Protected Shallow Foundation (FPSF), where insulation is used on the outside of the foundation to trap ground heat (and some residual heat from the home) under the house so that the concrete foundation walls do not have to go below frost depth (typically 42 inches in our area).  In fact, the foundation walls on this home only extend 14-16 inches below the final grade around the house.  This cuts down significantly on excavation and concrete costs, and makes it safer to work on since the “hole” dug for the home is only a little over a foot or so deep.

Like the vast majority of builders, typically we have poured our foundations in three parts: footings, walls, and slab.  In order to minimize the amount of trips by the concrete contractor, we combined the footings and walls into one pour.  It is a 12″ wide by 16″ tall footing/wall reinforced by rebar.  We also inserted J-bolts upside down into the wall to connect it to the slab later.  You can see how the footing/wall was formed and poured in these photos:

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Next, after the underground plumbing was complete, the inside concrete forms were stripped away and the inside of the foundation was filled with sand and compacted.  The outside forms stayed on to act as a form for the pouring of the slab later:

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IMG_8892 Next, we laid down the under-slab insulation layer.  We chose 2 inch thick (R-10) Dow extruded polystyrene (XPS) because of it’s excellent thermal properties, crush resistance, and the amazing gift-in-kind program that we have with Dow, where they donate their foam products to Habitat affiliates all over the U.S. and Canada.  Thank you Dow!!!

IMG_8913IMG_8911Next, a layer of polyethylene sheeting was placed over the foam layer as a vapor and radon gas barrier, then the concrete slab was poured on top of that.  The outside metal forms were stripped off and the foundation is complete.

The benefit of this type of foundation is that the entire slab of the home is thermally isolated from the ground under it, which means no cold slab under your feet and drastically reduced heat loss into the ground during the winter.

For more information on the Dow gift-in-kind program with Habitat, click here:

http://www.dow.com/en-us/about-dow/initiatives-and-partnerships/habitat-for-humanity

Excavation

We have been blessed with a beautiful building lot in a nice neighborhood in the northeast area of the city of Kalamazoo to build our new home.  It is about 66 feet wide by 300 feet deep, with the back half of the lot being wooded.  The family assigned to the home is working hard on their requirements for home ownership, including the 500 required hours of “sweat equity”, where they work on site to help build their own home and the homes of other partner families.  On top of that they must attend financial literacy courses and home maintenance courses to be sure they are ready for home ownership.

The photos above show the excavation of the lot. There was a home on the lot several years ago, so we had to remove several pieces of buried foundation to get back to a stable surface on which to build.  We chose to build on a slab for several reasons, primarily for cost (to keep the home affordable for the family), ease of construction, reduced risk of water issues from flooding (basements in Kalamazoo are notoriously wet from the high water table), and energy efficiency (less volume to heat and cool).  Another benefit of a slab home is the improved safety for volunteers building the home.  Many of the injuries and deaths in construction each year include falls into holes (basements) and entrapment in excavation collapses.  By building on a slab we eliminate both of these risks for our staff and volunteers.

Design phase

We were extraordinarily lucky on this project to have had our local chapter of the American Institute of Architects (AIA) contact us to offer their help with the design of a home.  A group of about ten local architects and Habitat staff got together for a charrette session to design the home using Habitat’s mandated house design criteria, which limit size and amenities to maintain affordability.  One of the guiding principals we used was that we wanted to build a home that didn’t look like a “Habitat home”.  Often, to keep homes affordable and easy to build, Habitat affiliates (including ours) have used stock plans that were designed for maximum utility with little attention paid to the look of the home and how it will compliment its surroundings.  The result of these “ugly houses” has unfortunately been the myth in the eyes of some that Habitat for Humanity is a low-quality builder, which couldn’t be further from the truth.  The AIA members were able to use their expertise in attractive design to help us work in low-cost options for giving the home a sense of style and place.

The floor plan below shows the layout of the home, with bedrooms and bath on one side and a large, open living space and kitchen on the other.  The home is about 1100 square feet in size, and incorporates universal design elements, making the home visitable to persons with disabilities, as well as easily adaptable to full accessibility if necessary.  This allows for a family to live in the home longer as they age without substantial, costly renovation.  Some of the elements of this design include 36″ wide doors on all rooms, wider hallways, a bathroom with room for wheelchair access and plumbing in the wall should the vanity need to be converted to wall-hung, and one no-step entry into the home.

In order to increase usable living space, the furnace and heat-recovery ventilation unit (HRV) will be installed in a completely conditioned attic room accessed by a pull-down stair unit in the laundry area.  This room in the attic will be super-sealed and insulated so that it falls within the thermal envelope of the home, and also serves as storage for the family’s belongings.  The water heater will be a hybrid, wall-mounted unit made by Eternal (model GU120), installed in a closet adjacent to the bathtub.  This location places the water heater in very close proximity to the fixtures using the most hot water: the bath and laundry.  In fact, except for the kitchen sink, the hot water lines to each fixture are all less than 12 feet long, with a few being just a couple feet long.  This ensures less wasted water and much faster hot water at the fixtures.

In the design process, effort was also made to try to conserve resources through smart design.  The home’s dimensions are all in 2 foot and 4 foot increments (not shown on the plan below), which match the dimensions of common building materials, therefore creating less job site waste.  In fact, the pitch of the roof (6/12) and overhangs (22 inches) worked out so that the distance from the eave to the peak is almost exactly 18 feet, meaning that it will take 4-1/2 sheets of roof decking to span to the top, eliminating waste from odd-sized cuts.

Note: the drawing below was not done by the architects involved in the project, but rather by our construction staff because we had a very tight time frame to get a building permit.  This is not a representation of their work 🙂

Chief Architect Premier X4_ 2427 Glendale plan - May 13, 2015 (no dimensions)

First post – June 17, 2015

Hello,

This is Tom Tishler, Construction Manager at Kalamazoo Valley Habitat for Humanity.  We have begun construction on a home in Kalamazoo, Michigan that we hope will earn the Department of Energy’s Zero Energy Ready Home (ZERH) certification when it is complete.  This is a rigorous program that uses the EPA Energy Star for homes version 3.0 and Indoor air plus certifications as the baseline for ZERH, and sets levels even higher to ensure that homes being built under the ZERH standard are, according to the DOE, in the top 1% of new homes being built for energy efficiency, indoor air quality, and overall cost of ownership.

It is our intent to share the practices we are using on this home in an effort to educate our community on the benefits of what we call “high-performance” homes, and the impact they can have on cost of ownership over the life of the home and the environment.  This home is very “green” by most green building program standards, but we hesitate to use that term because we feel it implies that the intent of the home is solely to be environmentally friendly.  This is an important outcome, and one we also care about very much, but not ultimately our driving reason for building in this way.  At Habitat we believe that by building energy efficient housing with our partner families we reduce the overall cost of ownership, ensuring that a family is not overly burdened with energy costs.  By building our homes according to the standards of the Indoor air plus label, we ensure the highest quality indoor living environment for our families, drastically reducing asthma-inducing triggers from chemical and environmental pollutants that are all too common even in many new homes.

We have worked hard to use the best building practices we could find, but nobody is perfect so we welcome constructive criticism of our project.  We also cannot overstate the importance of our volunteers, who have and will continue to contribute many hundreds of unpaid hours on the project by providing high quality, dedicated work in helping others in their community.  From the foundation to the last coat of paint, volunteers will provide the vast majority of labor in building the home, and we are extremely grateful for their work.  Over the next several months we hope to post as often as possible to keep everyone updated on the progress of the home, which we hope to complete in the winter of 2015.