WestCon Tribune

January 2008

Retrofitting With Lightweight

Insulating Concrete -

Tips For Solving Design Challenges

and Avoiding Problems

Presented By: Phil Dregger, DNG Group

Abstract: Lightweight insulating concrete (LWIC) has been used for many years to achieve positive drainage on flat roofs. Most of these roof systems have performed well. Some have not.

Our January meeting presentation will overview LWIC systems used today and compare the attributes and limitations of LWIC systems to taper board insulation systems. For example LWIC is re-useable (green) and less costly for large complexly shaped roofs but weighs more and incorporates more moisture in the final system than rigid board. Several case histories will illustrate how to overcome challenging but commonly encountered situations – avoiding prohibitive costs associated with raising equipment, avoiding wind damage due to premature deterioration of base sheets, avoiding inadvertent compromise of fire and wind ratings, avoiding removal of existing LWIC decks that are wet or have low pull-out values.

Biographical Information:

Westcon member, Phil Dregger is a professional engineer, registered roof consultant, a Principal of Pacific Building Consultants, and a past director of the Roof Consultants Institute (RCI). Mr. Dregger has over 20 years experience designing and investigating problem conditions for the full range of low-sloped and steeply sloped roofs as well as for plaza deck and below grade waterproofing systems.

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