Replies

1. 
   user-1087436 | Jul 18, 2012 01:24am | #1

   ?? From what I've read, I thought the furring strips were supposed to be fastened to the framing, but the siding itself was fastened to the vertical straps. That's what it shows in the diagrams.

2. 
   user-1037041 | Jul 18, 2012 01:33am | #2

   What Gordon said. You need to fasten your furring strips through the sheathing to the framing lumber. Then, fasten your siding to the furring strips.

3. 
   albertrooks | Jul 18, 2012 01:34am | #3

   Richard,

   The general rule is to choose a fastener length for the battens (which are supporting your siding) that will allow 1-1/2" penetration into the framing. Once that is done, then the siding fastener is chosen for the siding type and thickness itself, and does not have to reach the framing.

   Btw... 1" diagonal limber sheathing... nice!

4. GBA Editor
   Martin Holladay | Jul 18, 2012 05:17am | #4

   Richard,
   Builders all over the country have had good success attaching a wide variety of siding types to 3/4-inch-thick furring strips. In most cases, the siding nails only penetrate the furring strips.

   Unfortunately, building codes haven't kept up with recent trends, however, and don't really address siding nail lengths for homes with furring strips. In your case, the issue is moot, since you don't have any rigid foam under your furring strips. Instead, you have solid lumber sheathing -- the best possible sheathing when it comes to holding fasteners. So feel free to use nails that penetrate 1" or 1 1/4" into your furring strips and sheathing if you want to.

   Here's what I wrote on the issue in a blog on fastening furring strips:

   "Once you have installed vertical 1x4 strapping over foam sheathing, your siding nails are embedded in only ¾ in. of wood. Is that enough?

   "Table R703.4 in the 2006 IRC (“Weather-Resistant Siding Attachment and Minimum Thickness”) specifies the required minimum fastener lengths for attaching siding. Moreover, in Footnotes n, p, and y — footnotes that apply to some, but not all, types of siding — the IRC notes that fasteners must “penetrate framing 1 1/2 inches.”

   "Confusingly, however, Table R703.4 provides no guidance to builders installing siding on furring strips over foam sheathing. The table anticipates several scenarios, including “fiberboard sheathing into stud,” “gypsum sheathing into stud,” “foam plastic [presumably without furring strips] into stud,” and “direct to studs.” Each of these scenarios deserves its own column in the table. However, there is no column for “furring strips over foam sheathing.”

   "Until recently, many siding manufacturers recommended that siding nails penetrate 1 in. or 1¼ in. into wood. That’s beginning to change, however. The Vinyl Siding Institute requires only ¾ in. of fastener penetration for vinyl siding; James Hardie Corp. accepts only 7/16 in. of penetration for fiber-cement lap siding.

   "According to building scientist Joseph Lstiburek, if you have any doubts arising from the fact that your siding nails penetrate into only ¾ in. of wood, just switch from smooth-shank nails to ring-shank nails. Unless you’re building near the coast in south Florida, ring-shank nails will be more than adequate, even when penetration into wood is only ¾ in."

   For more information, see Fastening Furring Strips to a Foam-Sheathed Wall.