An Innovative Application for an Old Product

A builder is finding a new use for Ventgrid, a drainage mat originally made for cedar roofs, applying it behind exterior siding instead. The product is a reinforced plastic mesh that creates a half-inch gap between the siding and the wall, letting water drain and air move in any direction to dry the wall assembly. This gap is what's known as a rainscreen, a small airspace behind siding that helps prevent moisture from getting trapped and damaging the wall over time.

The mat fastens to the house at pre-punched points, and siding goes on top of it. One advantage is flexibility: it works with vertical, horizontal, or shingle-style siding without needing different setups for each. A separate closure piece fits at the bottom of the wall, letting water and air out while keeping bugs from getting in.

For a homeowner, this matters mainly if you're planning new siding or a full re-side of your house. A rainscreen gap behind siding is one of the details that helps siding and the wall behind it last longer by staying drier. Ventgrid is one option a builder might use to create that gap, regardless of what siding style you choose. If you're budgeting for a siding replacement, it's worth asking what drainage or rainscreen approach will be used behind the new material, since that affects how well the wall holds up over the years.