Fiber Cement Siding Ground Clearance
user-7303682
| Posted in General Discussion on
I recently installed fiber cement siding panels on the garage. Unfortunately the foundation of the garage has sunk over time so I wasn’t able to get the proper 6” clearance. It ranges anywhere from 2-4” I painted the bottom edge of the siding to help seal and protect the panels.
My concern is the siding will still fail. What are some things I can do to help protect the bottom edge of the fiber cement siding from water splashing on the ground. I already have rain gutters. Not sure if adding more would help. Any advice would be appreciated.
Replies
I think you're worrying too much. I've used FC siding in ground contact. Not ideal, but it has held up.
I wouldn't concern yourself with the siding failing, but if you are in an area with subterrainean termites you want to be sure that there is no concealed path from the earth to the framing.
FC in ground contact no problem? Wow, I hope you aren’t a professional FC installer. :-) FC absorbs water, lots of water, which will at the very least make the paint peel and at worst rot the framing behind it. Painting the edge won’t do much if the back near the bottom isn’t completely sealed. When the FC absorbs all that water it’s going to transfer it to the sill plate and rot it, or if it’s a PT sill then the bottom of the studs. Looks like you have 2 choices IMHO, short of removing, trimming, and replacing the bottom with a skirt: One, leave it alone, and when the bottom deteriorates (remember though, your framing behind may be rotting away while you wait) saw a horizontal line to cut away the bottom 6-8”, slide flashing up behind the siding and put a skirt board on, or two, do it now.
This is what I figured would need to happen. I am assuming use 5-6" wide PVC for skirt board? Another question what would be the best away to do this? I can layout a consistent line across the wall of the garage and follow that line with my circular saw. However, even if carefully follow the line there will still be some variation in the cut. Do I just hide this variation by filling the area between the skirt board and fiber cement board panel with caulk and paint?
I use a track saw. I drilled small holes in the track so I can screw the track to a vertical surface (like siding). If you don’t have a track saw you can screw a straight board to use as a guide with a Skilsaw. Slow and steady (and masked!). I would use 1x6 or 8 for the skirt. The other consideration is what to do at the top of the skirt where it meets the flashing. If you use painted aluminum z flashing it will bend over the 90 degree edge of the flashing, which could be all you need, just remember to leave a little gap between the siding and skirt so it doesn’t collect water (and paint the cut edge of the FC). You could also use a drip cap on top of the skirt, but the ready-made PVC ones have a lip that goes under the siding that may not work for this type of siding, they’re made for bevel siding. I make my own by ripping PVC stock at an angle. The flashing would go behind the siding and over the drip cap.
"The other consideration is what to do at the top of the skirt where it meets the flashing. If you use painted aluminum z flashing it will bend over the 90 degree edge of the flashing, which could be all you need"
I am trying to imagine this. Is there a photo you could share?
I just realized that I wrote if you use flashing it will bend over the flashing! Duh, of course I meant the flashing will bend over the skirt board. I can see why you didn’t understand what I meant. I hope the images cleared that up.
I didn't mean to suggest that ground contact would be no problem, but just that a little less clearance than 6" was not particularly worry some. Since I am in an area with subterranian termites, ground contact is never acceptable.
Mikemahan3, just to clarify, my comment about ground contact was directed at Andy. But the OP did say the siding was as close as 2” from the ground, which is way too close.
1st photo shows flashing with drip cap, 2nd is just z flashing over skirt.
Thanks for the photo. Would you apply caulk? If yes in what area? Thanks
Maybe, but the flashing should be doing all the work. Two places come to mind: If you do a drip cap then caulk on top of the skirt, if you don’t do a drip cap, same thing, on top of the skirt. If you have a 2nd pair of hands you might be able to attach and caulk the flashing to the skirt board before sliding it up into place as a unit.