Builders who like to include a vented rainscreen in exterior walls can nail up wood or plastic furring strips before installing the siding, or use a plastic mesh such as Benjamin Obdyke's Cedar Breather under wood shingles on walls or the roof.
Now they have another choice, a plastic grid called Ventgrid that can be used to create a gap under siding, roofing and flooring. First introduced in eastern Canada four years ago, it's become available in the U.S. within the last couple of months. Full article here