Drainage Plane Behind Vinyl Siding

There are lots of products and methods on the market today for creating drainage planes.

Drainage plane behind vinyl siding. Above the window is the same deal water can drain out air can flow in. With vinyl and aluminum siding the drainage space is more pronounced and furring is not necessary. Building america recommends a gap of at least 1 16 inch behind lap siding and a drainage space of inch between stucco and plastic house wraps to control liquid phase water penetration. For single family construction james hardie recommends installing a 90 efficient drainage plane or a 3 8 inch air gap i e.

Since you have tyvek you re all set. A 1 inch air gap is needed behind brick veneer as required by the 2009 international residential code irc baechler et al. Drainage planes building paper house wrap etc allow any moisture that does accumulate behind siding a chance to drain away harmlessly. So why use a drainage mat product behind your stucco cultured stone man made stone thin brick hardboard siding or other veneer.

Ideally wood siding should be installed over furring creating a drained and vented air space between the drainage plane and wood siding. Behind vinyl siding you definitely need a water resistant barrier wrb. With wood siding the drainage space is typically intermittent and depends largely on the profile of the siding. Siding is applied directly over the drainage mat so water can drain out and air can flow in.

Ideally wood siding should be installed over furring creating a drained and vented air space between the drainage plane and wood siding. The air space between siding and sheathing should also allow humid air to escape. Which is like the top of the wall. Below the window air can flow up and out behind a notch in the trim board.

With vinyl and aluminum siding the drainage space is more pronounced and furring is not necessary. Rainscreen between flat to wall siding and the water resistive barrier as a best practice. It makes its own drainage gap. Regardless of the type of siding you re using a drainage plane can drastically improve the long term performance of the siding and add another layer of protection for keeping water out of the house framing.

However none of these products does a great job at draining water out from behind the siding materials or allowing the back side of siding to dry out.