Green Casa Maryland: A Marvel in ICF Construction and Sustainability

Green Casa Maryland is a nonprofit committed to showcasing sustainability in construction. To do this, they built a beautiful 5,200 square foot, LEED certified, net zero model home. The team at Green Casa Maryland came to the conclusion that the only way to accomplish this goal is to pair many of the most efficient materials available, starting with Insulating Concrete Forms. Pairing ICFs with triple pane windows and R52 insulation in the ceiling was key to completing this feat of efficiency and sustainability. The house is so impressive that it is recognized as a finalist at the 2019 ICF Builder Awards in the category of Large Residential.

Project Information:

Name: Green Casa Maryland
Location: Cabin John, Maryland
Size: 5,200 Square Feet
Square Footage of ICF Used: 3,120
ICF Installation Time: 10 days
Total Project Construction Time: 24 weeks
Time Saved by using ICF: 2 weeks
Website: http://www.greencasamaryland.org/

Complex design and Creative Solutions

Green Casa Maryland is not only a feat of end-use efficiency but also in construction. The complexity of the project was increased by the fact that the home has 39 windows and doors increasing the amount of planning necessary for a successful build. Openings are marked on the plans and the foundation and cut, braced, and bucked as the walls go up. Moreover, the open design of the home requires special beams to support the second floor which was notched and cemented into the ICF walls.

One of the goals in building this project was to have virtually no waste. With any ICF project, there are sections where blocks are cut and implemented into the wall. BuildBlock is specifically designed to assist in a low/no waste build. Low waste features include a 1” repeating cut lines, webs 6” on center, and a 1” repeating interlock pattern) make it so that you have very little waste on site.

Scraps of BuildBlock added to the wall cavity

Even though these features make BuildBlock the leading ICF for people who want to cut down on their waste, it does take some effort to finish a job without any trash. The team at Green Casa Maryland found a unique way to reclaim all pieces of unused BuildBlock. They took all of the leftover ICF on their site and implemented into the upstairs loft as a preliminary source of insulation. The loft utilizes 2×6 studs so GCM cut and glued thousands of pieces of BuildBlock into the wall cavity and then spray foamed the cracks. This creates a job with no waste and adds rigid foam insulation to an area of the house that really needed it. Even other companies who sponsored elements of this project have been blown away by GCM’s commitment to the goals of the build.

“Most home builders have giant trash containers on site–we had none.”

Brett Kimberlin, Green Casa Maryland

Challenges and Craftsmanship

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One challenge to this project is the fact that it was begun in the dead of winter and the ICF construction had to work around a great deal of snow and cold weather. The project utilizes Helix Rebar that had to be added to the concrete mix on pour day. There were some initial challenges with finding a concrete company that would work with Helix and pour in such a harsh environment but the pour went exceptionally well with beautiful results.   

The craftsmanship of the Green Casa Maryland home is extraordinary. The ICF contractor did an exceptional job and had to deal with ensuring that all the walls were perfectly straight and that there were no voids when using the Helix. Even though there are 39 windows and doors of a dozen different sizes and configurations, there were no bulges, honeycombing, spills or breaks. When the Intus windows and doors arrived by shipping container from Lithuania, they fit perfectly into the openings made by the contractor. 

The design of the home is beautiful and unique. It is three stories and a bright open concept. The exterior is a combination of cedar and chocolate gray fieldstone. The interior is beautifully designed with 3 types of cedar. From the front, it is a simple lodge type design but from the back, it looks like a Swiss chalet. The home has won several awards including the “Excellence in Concrete” award for the innovative use of concrete and Helix in the ICF. 

Exceptionally Efficient

This is a LEED, Energy Star, and NGBS certified home with a HERS index rating of -4. The home includes 42 Sun Power solar panels and 2 Tesla PowerWalls. These components produce more electricity than the home uses making it a net zero home. Green Casa Maryland has given over 120 tours of the home to professors, students, contractors, civic leaders, and ordinary citizens to educate on the importance of sustainability. A number of people considering ICFs as a construction method toured the property and chose to use ICF.

Dozens of companies participated in the Green Casa Maryland project and are all listed on the Green Casa Maryland Website, which has become a nationwide resource on how to build a sustainable home. The home includes LED lighting, Energy Star appliances, triple pane windows and doors, rain gardens, drywall that absorbs VOCs, no VOC paint and flooring, a heat ventilation recovery system, the first greywater system in this county, heat pump water heater, mini split HVAC, a nonpolluting wood burning fireplace, and low flow toilets and faucets (just to name a few).

A Finished Home to be Proud Of

The home was completed within budget and on time and Green Casa Maryland is very pleased with the finished product. “We are very satisfied with the end result and the fact the home continues to attract tours and our websites sustained popularity.”

Green Casa Maryland is a unique project that was supported by scores of companies nationwide that wanted to be part of a project to promote sustainability. BuildBlock is proud to be the primary wall system for this incredible home. The team at Green Casa Maryland chose BuildBlock for this unique project because of its “the product’s ease of installation and BuildBlock’s great customer service. We couldn’t be happier with our choice!”

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