Cedar shingling a wall–vertical trim water concerns?
Ryan_SLC
| Posted in General Questions on
Hi there.
I am going to do some individual cedar shingle siding areas that will abut trim.
With Hardie, you caulk the seam. But with cedar shingles? I’m at a loss. 1/8 expansion joint are recommend between each single. So how do shingle edges stay water tight?
All I’m finding is weaving or not, but that’s not my plan given the shingles will contained to a single wall outlined with pvc trim boards.
Thank you so much for your help!
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There should be a WRB (aka housewrap) or a "spline" material such as #30 felt paper behind the joint. Many builders I know also bed each shingle in sealant where they meet the trim. I prefer to leave it open and pay attention to the flashing detail at the bottom of the window so any water can drain readily.
With Hardie Plank, I kinda have been working with water, mostly, won't get back to the house wrap. It sounds like with cedar shingles, you are expecting it to get back there.
Thank you!
I always aim to make the house 100% watertight before applying the cladding. The cladding is there to deflect most of the stormwater but some will always get through, regardless of the system.
I know the house wrap is the actual drainage of water. I didn't like your comment that some glue the end piece onto the house wrap. I think you're right to not do that.
Because they are accent areas separated by trim at the bottom (lower is Hardie plank,) any opinion on nailing up, but not sealing, an additional flashing strip to direct the water down but off the house wrap as much as possible?
There are several ways it can be done but it depends on several factors--is the trim flat or does it project? Does the Hardie Plank butt tightly to the bottom of the trim, go into a rabbet or does the trim sit over the planks? You wrote that the shingles will butt against the trim--is that on the sides only or also at the trim? Or do you want the first course of shingles to lap over the trim below? Do you have a rain screen, and if so, what is it? Is the WRB also your air control layer? How windy and rainy is your site?
Back to your original question, the shingles should always have three layers at any location. Traditional in New England is 5" coursing (aka "to the weather") with 16" shingles. Joints between shingles should be offset at least 1 1/2"-2" from those in the course below, and nailed 1" from each edge and up from the bottom, so water can always drain readily and you won't see any nails.
Wonderful info. Thank you.
PVC flat trim on the vertical edges, proud of the cedar.
PVC flat trim on the horizontal bottom separating the cedar and hardie. Drip z bar flashing at the top of this horizontal trim, drip flashing 3" up on the cedar side. I assume drip edge not at the bottom as well.
6mm rain screen mesh mortairvent. Perhaps not sufficient air, but cedar will only be top accent area, semi assumed to be protected a bit by overhang areas.
I suppose flashing tape isn't out either for these vertical edge seams...
Thank you for the help. Adding cedar shingle for look. I live in Utah, where this is not usual cladding opposed to coastal.
I love a good shingle job, but if you're already using Hardie, have you considered the Hardie shingle panels?
https://www.jameshardie.com/products/hardieshingle-siding
Might be easier to detail into the rest of the Hardie you're already using.
It's a good point to make for sure.
I personally feel like the hardie shingle always has on off. It's too flat in color and doesn't stick out enough. Usually it looks off in at least one area, usually the top. And that's done with a professional installer, which I am not :)
So my idea was, if it's going to look off because I install it, might as well go with the real deal.
But your comment does make me rethink on it.
Welp, my choice was made easier. None of the local places I can buy sell HZ5, only HZ10.
Nice job Lowe's for selling HZ10 (warm weather) only in Utah.