COLUMN BUILDING SCIENCES will get wet and stay wet forever. Under the plastic it can dry into the granular layer. Memo to everyone. With insulation you absolutely need a granular layer with no fines to act as a capillary break, and further note that the only insulation that will work is an extruded polystyrene. Are we done yet? Nope. Wood likes to move and no power in the universe will stop it from moving. It moves with relative humidity changes, as it is a hygroscopic material (Figure 9). In most places the interior winter relative humidity is low (typically 30%) and high during the summer (typically 65%). That means the wood flooring is going to float between 6% moisture content by weight and 12% moisture content by weight. Using "Joe math" that is a 6% seasonal swing. If you install wood flooring at 6% it will buckle when it goes to 12%. If you install wood flooring at 12% it will shrink and leave big gaps when it goes to 6%. Old guys knew this and conditioned wood to the mid-range moisture content it would see during service. For most of the lower 48 states that would be 9% moisture content by weight. Most people have forgotten about this; so the folks who make wood flooring typically precondition the wood to 9% before they ship it and cross their fingers. Flooring manufacturers also like narrower planks as that results in more joints that can accommodate more movement. Unfortunately, the trend is to wider planks as they are currently "in style." And don't forget to leave gaps at the perimeter of rooms. Did I mention that wood likes to move-even "waswood"? So how do you handle the movement if you don't condition the wood and like wider planks and don't like gaps? Consider a floating floor. New to the technology front-only a half century of experience to go on. Handles the movement part and is great for sound attenuation as the slip surface is often a thin foam layer. Ah, style and a lack of knowledge coupled with wet concrete makes you wonder if walking the plank is not so bad an idea. www.info.hotims.com/49810-5 N OVEM BER 2014 ashrae.org ASHRAE JOURNAL 49