Which rainscreen?
Josh7447
| Posted in General Questions on
I have read Martin’s article “All About Rainscreens” and I’m convinced we need one. Anyone have any experience on which product to use. My lumber yard is trying to sell the DuPont rainbatten which looks like a good product. However rainscreens are not common around here and mti sure cavity appears to be an easier install as its more like house wrap. Anybody have any experience with these products? I liked a product called roll on rainscreen but at $3+ per ft for material, it’s not an option.
Thanks
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Josh,
Our lumberyards all sell plywood strips for rain-screens. If yours don't, I'd rip them down from 1/2" CDX plywood. Except under a very few claddings, like shingles or shakes, I don't see any advantage to the proprietary products.
1x3 spruce strapping is a common, readily available, non-plastic, and inexpensive material and works great for rainscreens. We do not need to use plastic.
Mason's lath is even cheaper (1/4"x1-1/2") and still available in bundles in most markets. This provides plenty of drainage space, except in Canada. Don't worry too much about rot, unless you live in a rain forest. The whole point of a vented rainscreen is to allow the back of the siding to dry out, and this means that the lath can dry out as well.
"Roll-on rainscreen" products are generally liquid applied water resistant barriers (WRBs). They take the place of the building paper and provide air and sometimes vapor management. They do not create the air gap necessary to create a true rain screen assembly. You would still need some type of furring strip.
The siding material matters. As Malcom mentioned above, shingles and shakes should be installed over a mat-style rainscreen material, like Obdykes Home Slicker. These mats, with an additional scrim layer are also appropriate for stucco claddings. I like the MTI surecavity behind stone veneers in wet climates. The plastic layer stops inward vapor drive, which can be a big deal in some climates.
Some have used strips of foam insulation. In some cases, StuccoWrap provides enough benefit with very low labor.
Some think that rot can sometimes be a problem:
"Pressure treated strapping is only required in high rain areas, though it is recommended in all jurisdictions. "
http://rdh.com/wp-content/uploads/2015/10/Residential-Insulated-Sheathing-----Installation-Guide-ROXUL-COMFORTBOARD-IS.pdf
Thank you all for the great advice! Here is the roll on product I was talking about. Looks great if your budget allows but I think I'll save money and use suggestions provided. https://www.rollonrainscreen.com/new-roll-on-stick-on-rainscreen
Hello Josh, I am the business administrator for Roll-On Rainscreen. I apologize if you received mis-information regarding pricing on our products. Roll-On Rainscreen is the most affordable furring strip on the market today. Roll-On Rainscreen and Roll-On Stick-On Rainscreen are both less than $1 per foot. Both products range from .45cents-.99cents per foot depending on the amount purchased. Roll-On Rainscreen is made to reduce labor & material costs. Roll-On's installed cost is about 25% less than utilizing PT Wood Furring. Please give me a call or email for any future projects. I would be happy to send you further information on our products as well. My email is [email protected]. Thank you! http://www.rollonrainscreen.com
Josh,
The disadvantage of plastic and metal materials are the they are non-structural and don't help provide backing for the cladding and trim.
If you use solid wood or plywood strips, the thickness of the sheathing + rain-screen will often be sufficient to support the cladding without having to hit the underlying studs. This is particularly useful where the siding has vertical joints that don't coincide with the underlying structure, or to support wide trim around openings. Materials that contribute to the structure also allow the possibility of mounting ledgers for roofs and decks outboard of the rain-screen cavity.
Josh, What cladding are you installing over top? As Malcom indicates there are certainly instances where mats are easier to work with than furring strips - I would argue for shingles, shakes and thin set masonry the proprietary mats help a lot.
In any case, pay attention to the detailing at transitions, windows and terminations.
Do you live near a sawmill? I'm using 3" wide larch, planed down to 3/4". It cost me 22 cents a linear foot, is wider than 1x3, and is a rot-resistant species.