Messages and Online Forum Q&A

Re: SIPs

From: info@builderswebsource.com
Category: Structural
Remote Name: 63.198.181.43
Date: 20 May 2001
Time: 01:52 PM

Comments

SIPs are Structural Insulated Panels -- pieces of plywood or oriented strand board (OSB) with an insulating foam core of specified width. There are three types of SIPs: Expanded Polystyrene (EPS), which is the most common, Urethane (PUF) (Polyisocyanurate) or Polyurethane, and extruded polystyrene. EPS typically has an r-value of 3-4 per inch thickness, while polyurethane typically has nearly double the r-value per inch (typcially 7-8). This means that polyurethane provides better thermal resistance per inch compared to EPS. This allows you to use thinner panels or achieve greater insulation capacity.

However, in a fire, polyurethane releases toxic cyanide gas. Of course, polyurethane is commonly found throughout the home in sofas, mattresses, chairs and padding. Attention to fire safety is essential when using PUF (as with any materials).

Furthermore, when building a home from SIPs, you MUST use mechanical air circulation and ventilation methods to draw in fresh air and exhaust stale, moist air. This requires an air-to-air heat exchanger or other suitable method. Failure to provide adequate fresh-air ventilation can result in unhealthy levels of indoor air pollution and outgassing.

For more information on SIPs, visit the SIP website at http://www.sips.org.

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