Siding replacement questions
I apologize in advance because I know that these questions have been discussed in the past but I couldn’t find them.
Question #1
We are creating a detail for adding 1/2″ rigid foam and a 1/2″ or 3/” rain screen vented at top and bottom. If we move the window out 1/2″ is this enough to do a good job of getting foam around the reset window if there is a wood interior trim that we are trying not to disturb?
Question #2
Should we use a 1/2″ furring strip or 3/4″? It seems to us that this comes down to the mechanics of fastening the siding (usually fiber cement.) If a 3/4″ furring strip is well fastened through the rigid foam to the framing, could it hold the siding nailed only to it. We would be disinclined to fasten siding to just a 1/2″ furring strip without reaching back to the framing with the fastener. Are we mistaken about this?
Question #3
Is fiber cement siding attached to furring strips on 16″ centers going to become wavy? This is a bigger issue as we think about our new homes on which we use advanced framing on 24″ centers. I also welcome ideas about this detail.
Thanks,
Hugh Stearns
Stearns Design Build
http://www.stearnsdesignbuild.com
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Hugh,
First, you want to make sure that the rigid foam layer is appropriate for your climate zone. Your plan to install 1/2-inch rigid foam will work if you live in Climate Zone 3, or in Climate Zone 4 if it isn't Marine Zone 4, but it won't work if you live anywhere colder. In Climate Zones 5, 6, 7, and 8, you'll need a thicker layer of rigid foam. This article explains why: Calculating the Minimum Thickness of Rigid Foam Sheathing.
Second: If you are installing rigid foam followed by furring strips, the furring strips have to be at least 3/4 inch thick so that you have something to fasten the siding to. For more information on this issue, see All About Rainscreens.
Third, your fiber cement siding won't be wavy if you do a good job installing it. Ideally, your studs and your furring strips will both be 16 inches on center.
Martin,
Thanks for the quick answer. Yeah, I should have said that I am the hot humid climate zone 4 of Texas. We had figured on 3/4" lath until we saw some of the details here on GBA. Some show 3/4" and some 1/2". You say, "Ideally, your studs and your furring strips will both be 16 inches on center." This does not account for advanced framing. Is there a solution in this situation? Should we modify the advance framing to 16" centers if there is siding on the project?
Thanks,
Hugh Stearns
Stearns Design Build
http://www.stearnsdesignbuild.com
Hugh,
Some siding manufacturers require that their siding be fastened every 16 inches. Other siding manufacturers allow fastening every 24 inches. Contact your siding manufacturer and read their installation instructions.
If your siding manufacturer requires fastening every 16 inches, that's the stud spacing you should choose.