Drainage Plane for Cedar Shingle Siding

Extend Siding Life with Drainage Planes

Cedar siding is beautiful and sure does make a statement architecturally but it comes with a serious price tag. So using methods and products that extend the life of such a big investment is important to me as a builder and you as a customer. The market offers many products that create a drainage plane behind siding and trim. In this article I want to share my experience and thoughts on HydroGap®.

HydroGap® Drainable Housewrap is a house wrap product that also creates a drainage plane, thus providing two major components for the exterior building envelope in one product. We recently used this product while building a lake house here in NH. The house was sheathed with ZIP System R Sheathing followed by the HydroGap® Drainable Housewrap and finally a combination of red cedar shakes and clapboards.

All Siding Leaks

One of the first things that a good builder learns early in their career is the fact that all siding leaks. Whether it’s beautiful cedar siding like on this house, brick, stone, or even vinyl, they all will leak at one time or another. Anyone that tells you differently doesn’t understand this topic very well. This is why using products that keep water and moisture out of the building frame is so important.

House Wrap

Old timers will tell you there’s no substitute for using tar paper under siding. There’s probably some truth to that and I’m still seeing some builders use it under siding. However, the last 20 years have seen advanced materials replace tar paper with house wraps like Tyvek and TYPAR. These materials are designed to stop air and water infiltration while allowing water vapor to escape. More recently products like ZIP system from Huber is a building sheathing product that has an integrated water resistant and air barrier impregnated on the surface, speeding up the building process.

These products certainly do a good job keeping air infiltration to a minimum and helping prevent water from getting into the 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.

Drainage Planes

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

Several of the products are specifically targeted at the cedar siding and roofing market like Cedar Breather. Most of these products look like a huge roll of thin Brillo pad like material. The thickness of the material creates a void behind the siding allowing water to drain down away from the siding.

Siding installers either love or hate this product as it can be difficult to install especially on walls with lots of trim. It can be quite bulky when overlapped so it takes some practice and patience!

Recently we tried a new product called HydroGap which is made by the same company as Cedar Breather. This product is a combination of both a house wrap and drainage plane.

HydroGap® Drainable Housewrap is the newest moisture management product from Benjamin Obdyke. This product allows construction professionals to Build Better™ by effectively eliminating excess moisture, thereby preventing the damaging effects of mold and rot. Its patent-pending one millimeter spacers allow at least 100X more bulk water to drain from a wall versus standard housewraps.

I really like this product for a couple reasons:

• Installation is much easier than some of the products like Cedar Breather. Just roll it out, staple it, cut with razor knife just like house wrap that all of us are accustomed to.
• If you’re going to install a house wrap, might as well install this and get the benefit of the drainage plane.
• The siding installs over it really nicely. We also ran it under all the trim which can benefit from better drying.
• Priced similar to house wrap.

Even though we used ZIP system on the house we’re building (we used the ZIP System R Sheathing which includes a foam layer) this product was used just for the drainage plane (the ZIP system has a water/air barrier on it already). We chose it due to ease of installation.

Drainage Planes Doesn’t Always Mean More Money

After working with this new product I’m convinced that we can provide a better end product for our clients for little to no additional cost. Products like HyrdoGap are easy to install, cost effective, and ultimately extend the life of our clients siding and trim. Be sure to check it out the next time you’re installing siding on a new home.