Pros and Cons of a Closed Joint Rain Screen: What You Should Know

A rain screen is a design and installation method to let your siding ventilate. The siding stands off the outside wall. A rain screen or 'rainscreen' lets your home or building breathe better. This can help minimize the mold. From the outside, most wood rain screens look alike. But they don’t perform alike. Before deciding, there’s a lot you should consider.

All wood rainscreens look pretty much alike from the outside - it's what's inside that counts

GOOD WOOD RAIN SCREEN

Closed joint systems are the most basic rain screen option. They are a good rain screen option. Not a great one. Wood furring strips keep the siding off the building envelope (outside wall). The ventilated air space between the furring strips is what makes it a rain screen.  Without back ventilation, wood siding will rot.

If you’ve ever seen paint peeling off old cedar siding, it’s usually not the paint’s fault. Sometimes it is poor flashing. But most times it is excess moisture in the siding. Trapped. With nowhere to go and nothing to do – except rot.

A closed joint wood rain screen only ventilates at the top and bottom, so it’s very limited. But it’s better than not having a rain screen at all.

Here's How a Closed Joint Wood Rain Screen with Furring Strips Assembly Works:

A CLOSED JOINT Rain Screen can only ventilate at the top and bottom 

Benefits of a Closed Joint Wood Rain Screen with Wood Furring Strips

• Provides back ventilation (except where the furring strips are)
• Allows some exterior moisture (rain and wind driven rain) to ventilate
• Allows some interior moisture to escape (except where the furring strips are)

Problems with a Closed Joint Wood Rain Screen with Wood Furring Strips

• This installation method only ventilates at the top and bottom of each wall cavity
• It is always imperative to keep the top and bottom clear of debris or the cavity won’t ventilate
• Placing the furring strips too close to the ground can lead to rot.
• If snow is higher than the bottom course of the siding, the cavity won’t ventilate.
• The furring strips themselves limit the amount of moisture being able to escape from inside the structure
• If the furring strips retain moisture, they become a liability and a potential to grow mold and rot

Common types of siding used for close joint rain screens are clapboard, shiplap and T&G (tongue and groove) siding profiles. This system is often lower cost up front than other rain screen methods.  This makes it a tempting option to keep the construction costs down.

However, the long-term costs, and maintenance costs are usually higher than other rain screen options.  The life expectancy of this type of system is usually in the 10 year± range.

BETTER RAIN SCREEN

Open Joint Wood Rain Screen with Furring strips:

An open joint wood rain screen with wood furring strips works better than a closed joint system.  Because it has more places for the wall cavity to ventilate. However, this method has the same limitations for furring strips problems and related issues.

Here's How an Open Joint Wood Rain Screen with Furring Strips Assembly Works:

An Open Joint rain screen assembly vents at the top and bottom. It also allows for convective air movement at the open joints. The furring strips are the weak link in this type of assembly.

BEST WOOD RAIN SCREEN

Open Joint Wood Rain Screen with NO Furring Strips:

An open joint rain screen with NO furring strips works best of all. This rain screen method is often referred to as a “pressure equalized” rain screen. There are no furring strips to limit the air movement in the wall cavity.  The Climate-Shield Rain Screen System is the best example of this method.

Open joint rain screen with no furring strips is the most effective rain screen assembly

The Climate-Shield rain screen method allows for maximum air flow. There are no furring strips to block air flow. That's why the wall cavity dries much faster than any other rain screen method. That’s why it performs better. No wood furring strips to get wet means the potential for mold and rot is minimal. That’s why it has a much higher life expectancy than other rain screen methods.

Want to learn more? Download The Ultimate Guide to Wood Rain Screen Siding now:

We hope you enjoyed this article. Please visit MataverdeDecking.com for additional information about rain screen installation options, check out rain screen galleries, choose your wood rain  screen siding species and more.