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RickC 10-05-2013 11:53 AM

Hardiplank sheathing issue first row- HELP!
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My sheathing stops above sill plate and part of the plywood decking (See photos). I am installing hardiplank and don’t know how to handle first row. (1) Should I add additional sheathing strip to cover area to extend to the bottom of sill plate or is there a way of installing first row and have thinner starter strip start at sheathing without doing this? (2) If additional strip is needed to cover sill plate, could this be a cedar strip instead of plywood as I have lots of cedar from old siding I can cut down? (3) If cedar strip is acceptable, can I make this strip ¾” in thickness which would be wider than the ½” sheathing above. This could also act is the starting strip. (4) How about the tyvek – could it go over the bumped out thicker strip (normally starter strip is nailed on top of tyvek)? (5) How far should hardiplank hang down below sill plate?

Clutchcargo 10-05-2013 12:23 PM

63 Attachment(s)
I would cover the entire area with plywood at the thickness of the existing sheathing. Then side as normal.

RickC 10-05-2013 02:11 PM

Thanks clutchcargo. Becasue I have so much cedar around, would there be an issue of using 3/4" cedar instead of 1/2" plywood like sheathing which would allow for the starter strip that hardiplank calls for. I would then overlap tyvek over the bumped over the cedar which is 1/4" wider than the plywood sheathing. If I use plywood strip to cover sill plate, I still need a starter strip about 1 1/2" wide by about 1/4"thick.
There may be reason not to do it this way, which I welcome any input on. Thanks

cortell 10-06-2013 06:58 AM

Curious. The first pic shows what appears to be a 2x4 rim joist under a 2x4 sill plate. The plywood ends above both. The second pick shows the plywood exposing only the rim joist. Is that correct?

RickC 10-06-2013 10:06 AM

I have post and beam construction with 1 1/16" plywood subfloor.

Gary in WA 10-06-2013 12:02 PM

That will work. You don't have the shear on the wall with it not reaching sill or a pt sill anyway...... cedar would dry much faster than adding ply there. Leave gaps between 1/4" filler strips for drainage on face of housewrap. Caulk the concrete/sill joint with sealant. Where are you located?


RickC 10-07-2013 11:03 AM

Thanks Gary- hope you can get back with me soon as I need some clarification on your response. Not sure what you mean when you say "that will work". As described above, I was looking at not using a separate 1/4" starter strip and have the filler cedar strip be 3/4" wide which would result in a 1/4" bump out that the first row of Hardiplank requires (note - sheathing is 1/2" plywood). I was then going to put tyvek over the filler the filler strip and then install hardiplank over that. The alternative would be to first install a 1/2" cedar attached to the sill plate, cover with tyvek, then on top of tyvek add a separate 1/4" strip for the bump out. Is there a problem with using 3/4" filler and tyvek over that or should I use the 1/2" cedar below sheathing, cover with tyvek, and add a separate 1/4" bump out cedar strip on top of tyvek? Also, not clear on what you mean by "Leave gaps between 1/4" filler strips for drainage on face of housewrap" - please clarify where the gap is that you are referencing.

I also live in WA (Longview) so you can know I started my siding project late with fall weather arriving.

hand drive 10-07-2013 01:19 PM

It looks ok to add the 3/4 as the sheathing. we sometimes put a hardie rip behind the first piece to make it angled ( about 7 degree) like all the rest of the siding will be so your 1/4" bumpout will not matter IMO. something else in case you did not check it- level around your foundation to find the lowest point and use that to start your siding. I've seen older homes with 4" difference (out of level) from one side of house to the other. that is where remodeling 101 comes into play... sometimes you have to make the first few pieces out of level and then fudge up to level as you work your way up the wall

Gary in WA 10-07-2013 02:13 PM

The added 1/4" thickness under the Tyvek will work. IMO, I may be nit-picking; it will cause a bump out in the drainage plane, though very slight. The drainage plane should be flat without any continuous friction/tension across the bottom row where the siding touches the thicker material creating a ridge-line in the housewrap to admit water as cement board siding is a "reservoir" siding, holds water -- similar but not as bad as cedar over Tyvek when tannins cause leaks from standing water;

You will get "perched water" and hydrostatic pressure which could mean water intrusion from the small ledge formed;

Much better to have the plane flat then add the shim material (on top the HW) for the angle-out with spaces left between shims for drainage of liquid water, if ever any due to exterior leak or vapor condensation from within.
With your 46" annual rainfall, I would use a drainable house wrap (rather than flat) if not a rainscreen system;

The gaps are between horizontal shim strips, leave a gap of 1/2" every 12" or so.

Describe the wall make-up please....


RickC 10-08-2013 01:44 AM

Thanks very much Gary for your thoughtful reply with lots of good information. I plan on cutting cedar down to 1/2" thickness to match sheathing and adding a seperate 1/4" strip later over tyvek. I had thought of using table saw to cut a 45 degree at the top outside corner of a 3/4" cedar to avoid a 90 degree ledge, but thought this would be too difficult because the distance from the sheathing to the the sill plate varies and would require different size filler srips. Also, Hardiplank people I spoke with today said they don't want starter strip to be much over 1".

I did see the rain screen wrap at a building center and could do some checking on that for bottom part of the wall slipped under tyvek above which is already on the wall.

The house was built in 1980 with 8 ft high 2x4 walls, 1/2" plywood sheathing, and now tyvek over walls instead of 15# felt paper orginally covering sheathing. The siding I took off was rougher looking cedar boards placed vertically which gave the look of T-111 siding. The cedar boards extended below sill plate. I didnt' see any signs of damage to sheathing when

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