APA - The Engineered Wood Association


Madison House: A Construction Laboratory

APA, the Southern Pine Council and the USDA Forest Products Laboratory Advanced Housing Research Center partnered together to build a 2,200 square foot demonstration home on the grounds of the Forest Products Laboratory in Madison, Wisconsin.

From the permanent wood foundation to the flashing around the chimney, this 4 bedroom, 3-bath two-story house showcases moisture-resistant building practices, the latest in energy efficient appliances and HVAC systems and 'green building' technologies advocated by the leading building science experts.

The Build a Better Home demonstration house serves as an ongoing classroom of better building practices:

  • A team of researchers instrumented the walls in an effort to monitor the moisture content and temperature behavior therein.
  • To test the house’s tolerance for elevated indoor humidity, the house's interior is maintained at 40% relative humidity during the winter months.
  • Each phase of the construction process was photographed and videotaped for future educational use.

The construction was completed in October, 2001 and the house is open to the public for touring.

Construction Phases

Permanent Wood Foundation

Madison House PWFWhat we did:
In place of concrete walls, we installed a pressure-treated wood foundation, also known as a permanent wood foundation or PWF.

Why we did it:
PWF's have numerous advantages: they can be installed in any type of weather conditions by the framing crew. This eliminates an extra trade and shortens the construction time; wiring and plumbing easily are changed; enhanced design flexibility.

Engineered Floor System

What we did:
We installed engineered wood I-joists, I-joist compatible glulam beams and Sturd-I-Floor panels.

Why we did it:
I-joists are strong, straight, and provide superior floor performance. Knockouts make wiring, plumbing and ducting fast and easy. Glulams eliminate the need for posts. The plywood Sturd-I-Floor is ready for the finish layer of flooring without an extra underlayment.

Finger-jointed Stud Framing

What we did:
We framed the exterior with 2 x 6 and the interior with 2 x 4 finger-jointed studs made from Southern Yellow Pine.

Why we did it:
High strength - Design values assigned for Southern Pine are among the highest for all softwoods.

Durability - Southern Pine is highly resistant to wear and has one of the highest nail holding capacities among softwoods. The finger-joint provides a straight framing member that resists twisting.

Fully Sheathed Walls

What we did:
We wrapped the exterior walls with 4’ x 8’ sheets of Oriented Strand Board (OSB). The 7/16” thick panels were spaced 1/8” apart and nailed 6” o.c. at the edges and 12” in the field.

Why we did it:
APA Rated sheathing easily meets building code wall sheathing requirements for bending and racking strength without let-in corner bracing. Excellent stiffness for the areas where stucco and brick siding will be applied.

House Wrap

What we did:
Wrapped the exterior walls and openings with a code-approved, weather-resistive barrier (WRB) shiplap manner.

Why we did it:
The barrier helps to ensure the integrity of the walls by keeping bulk liquid moisture away from the wall surface.

Window Flashing

What we did:
We followed the recommended procedures from ASTM window guidelines using method A1. The flashing depths around the windows were 9" minimum.

Why we did it:
Most of our windows had integral nailing fins, which are seamless, waterproof flanges. Method A1 lists the specific order of steps for this type of flange with the weather-resistive barrier already in place.

Composite Shingles

What we did:
We chose a locally produced composite shingle made from recycled plastic and sawdust for the roof shingles.

Why we did it:
This shingle uses waste products to produce a heavy, durable roof cover. The shingle required no special fasteners or unusual installation procedures. The tabs were produced in 48” lengths to a depth of 24” inches.


What we did:
Installed moisture pins in various wall cavities from the basement to the second floor. The pins were embedded in the exterior OSB sheathing and then wired to computers.

Why we did it:
One of the primary goals of this demonstration project is to quantify the effects of moisture on the building envelope. From the inside of the house, we will load the humidity levels to around 40% and measure the OSB’s response.


What we did:
Installed blown-in cellulose insulation. The product is applied to the stud bays with a special applicator. It goes in damp (25% moisture content) and dries to the ambient atmospheric moisture level (12-15%) in about 36 hours.

Why we did it:
We wanted our house to meet or exceed the stringent requirements of the Wisconsin Energy Code. This insulation restricts excessive airflow within the cavities and provides our home with R-20 walls and an R-38 ceiling.


What we did:
The eastern or front side of the house receives brick, the garage side will be stucco, the rear or western exposure is APA Rated panel sheathing and the south side is APA Rated lap siding.

Why we did it:
We wanted to expose various siding treatments to the elements and measure how much, if any moisture penetrates the surface when proper flashing and sealant techniques are used consistently throughout the building.

Madison House Project Partners

Southern Pine Council
Advanced Housing Research Center
USDA Forest Products Laboratory

Project Sponsors
Andersen Windows
USP Lumber Connectors

Windsor Homes

Research Demonstration House Reports

September 2006 (PDF)

June 2004 (PDF)