Characterized as strong, durable, and energy-efficient, a new wall system for housing called insulating concrete forms (ICFs) is emerging as an alternative to lumber wall frames. ICFs are hollow blocks, planks, or panels that act as forms for cast-in-place concrete walls. They can be constructed of rigid foam plastic insulation, cement and foam, cement and wood, or other appropriate insulation.

Due to rising costs and varying quality of framing lumber, homebuilders are increasing their use of ICFs -- although added engineering costs make ICF homes slightly more expensive than homes with wood framing. To improve the affordability and acceptance of ICF homes, HUD's Office of Policy Development and Research recently released a report with guidelines on the design, construction, and inspection of ICF wall systems in Prescriptive Method for Insulating Concrete Forms in Residential Construction.

Based on thorough testing and research, the prescriptive method section of the report outlines minimum requirements for ICF systems including wall thickness, termite protection, reinforcement, lintel span, and connection requirements. It highlights construction and thermal guidelines for ICFs and explains how to apply the prescriptive requirements to one- and two-family homes.

The commentary section provides supplemental information and the engineering assumptions and methods used. Appendices contain step-by-step examples of how to apply ICF requirements when designing a home and provide engineering technical substantiation and metric conversion factors.

Builders, code officials, design professionals, and others will find Prescriptive Method a helpful guide to using this new material for residential construction.