Common Questions

WHY ARE SIPs SO MUCH STRONGER?

SIPs are a structural composite, like an “I”–beam. The skins act like flanges and the rigid core is similar to the web.  The three components work together, rather than against one another. This composite assembly yields stiffness, strength and predictable responses.

HOW DO SIPs REACT TO FIRE?

Fire requires three components, fuel, ignition and oxygen. SIPs have no “air” within their solid cores of insulation. The fire cannot “run up the wall” cavity even when balloon framed. SIPs have passed every standard fire test that is required of wood based or type V construction. A key element of fire safety is protection of the SIPs and any other underlying structure with thermal barriers like gypsum wallboard. Earthcore has combined a polyurethane foam core with a fire rated OSB product which allow Earthcore customers to use SIPs for firer rated demising walls.

WHY ARE SIPs MORE ENVIRONMENTALLY RESPONSIBLE?

• Less job site waste means less landfill use.
• Lower heating bills translates to lower energy (fossil fuel) consumption.
• Use of fast growth harvested farm trees rather than old growth forest.
• Up to 35% less raw timber use in SIP buildings.
• Lower reported embodied energy cost.

HOW DO SIPs SAVE SO MUCH LABOR?

Determining what cuts to make to the walls is done on a computer screen making a more accurate cut. Easily recognized components are shipped to the site for assembly, rather than waiting for interpretation of blue prints. SIPs also come in much larger dimensional sizes than other building materials. An average frame crew can install 1½ time more SIPs wall square footage per day than traditional framing. Consequently the project is dried in from the weather quicker and other subcontractors can get a head start on the work that needs to be done.

Polyurethane v.

Polysterene

The question often arises “What is the difference between Polyurethane and Polystyrene foam.” The review below is a general comparison and does not necessarily represent a particular manufactures product.

There are five main differences that need to be evaluated:

1. R-value- Polyurethane has an R-value of 7.0 to 7.5 per inch whereas polystyrene has an R-value of 3.5 to 4.0 per inch.
2. Chemical resistance- Polyurethane is resistant to damage caused by other chemicals. Polystyrene is subject to attack by petroleum-based solvents such as gasoline, many types of insect sprays and common glues such as “Liquid Nails.”
3. Fire damage- Polyurethane is a thermal-set plastic and does not melt. It is not damaged until the temperature reaches 700 to 800 deg. and then it “chars.” Earthcore uses polyurethane that has been treated with flame retardant and has been tested as a Class 1 foam. A Class 1 foam means that when burned, an external heat source is required to sustain combustion. If left on it’s own, the foam will self extinguish. Polystyrene on the other hand will soften at 190° to 220° and melt at temperatures of 240° to 300°. Many polystyrene products are also classified as Class 1 foam and will not sustain combustion, but melt at a very low temperature.

4. Connecting method- Most panel to panel connections require separate splines that must be installed and require 4 rows of nailing to attach. Earthcore SIPs have a connecting “tongue” that is factory installed eliminating the need to install the splines. This connection system only requires 2 rows of nailing, reducing total install labor.

5. Material waste- Panel material is sold by the square foot. The standard process is to make the panels full size and then cut or remove the material for the windows and other openings. This waste material is included in the total cost of the project. Because of it’s unique manufacturing process Earthcore does not manufacture the “hole” so there is no charge for that material. This difference can lower the cost of a project as much as a $1,000 per home.