Hardie siding - studs or OSB

[jtrux]

I'm installing some Hardie lap siding and before I get too far I wanted to get opinions on attaching it directly to the studs or is it preferable to attach to OSB? I know both are acceptable but is one method better?

 

[karoc]

I put it on my garage and nail to studs cause its more solid of a hit using a nail gun. Problem is sometimes the nail would blow through the Hardie which is a no-no. Watch few Youtubes see how to do the right way which I'm sure there are several ways to install it property and just as many to do it wrong. Which sometimes I think I found the wrongs

 

[Copymutt]

So, not planning on weather tight eh.

 

[toolchaser]

I nailed it vertically to studs. Some of the horizontal runs, esp. the trim were in the osb only, they hold but not as well as in the studs. I ended up hand nailing mine because of the inconsistent nail depth issue. This was Hardie in sheet form I think the lap siding is more consistent density

 

[WNYflyer]

Assuming this is going on an exterior wall of a structure subjected to wind loads, if that is the case do you need sheathing anyways on the exterior of the wall to act as wind bracing for the wall or to brace bearing wall studs from buckling from vertical loading ? or do you perhaps have let in diagonal bracing to act as the wind bracing for a wall which may allow you to forgo sheathing and attach directly to the studs? I don't believe let in bracing is considered to brace bearing wall studs subjected to vertical loading, not sure on that. I believe the installation instructions show both conditions. Whether they meet current code I have no idea.

 

[firetruck41]

OSB, Tyvek, and then Hardie. Nail it through the OSB to the studs; make sure you mark them out ahead of time. Use a siding nail gun and a good pressure regulator on your air line to get consistent nail drive without blowthrough or cracking. Use the flashing plates behind the joints, and only use factory primed ends on the joints. (Expensive, and takes some effort, but eliminates moisture/delamination and buckling problems later). Space with 1/8" gap and don't caulk. Bury all your cut ends on the corner or end trims, and caulk them with OSI Quad Max.

This!^^^
Exactly what I did on my house. Solid! And looks good.

 

[yeldogt]

To get the best results it should be snug and with OSB ,,, it should be nailed at the studs. All to often it overdriven.

Actually -- it's best to use a rain screen .. I like the Tan one with the small bumps (forget the manufacturer) Some people are going back to felt and strapping.

Tvek is overrated .. everybody uses it .. but it's never installed correctly.

I like to give a bit more lap with Hardie ... so I buy the next wider product and increase the lap. The lap line on the product is very small -- this gives a bit more strength with the larger lap. no wave

As reported .. don't caulk the butts (flash) .... use the Hardie kit and paint the cuts. I like the pre-painted. Takes a little more time to be careful .... but it's done

 

[jtrux]

OSB it is.

As for not caulking the joints, why? I had anticipated flashing and caulking just because I figured the caulking would give a better finish.

 

[yeldogt]

OSB it is.

As for not caulking the joints, why? I had anticipated flashing and caulking just because I figured the caulking would give a better finish.

Siding expands ... even with wood siding ... no caulk.

What do you think they did before caulk?

Caulk fails ... some of the newest glues may work for 30 years inside with little expansion and contraction. But outside ... it eventually fails. With pre-painted the caulk joint will not match in the sun after a while.

I never use OSB -- but that's me.

Years ago when you did a window and door you flashed the sides -- simple butts to the frame with the siding

 

[Kenstone1]

OSB it is.

As for not caulking the joints, why? I had anticipated flashing and caulking just because I figured the caulking would give a better finish.

Ther are detailed instructions on installation at the hardie website, even some videos on it.
You'll read there about no caulk and putting a piece of black roofing paper behind every joint before installing the 2nd length of siding, leaving a gap between the butted ends...
No better source imo,

here you go:
https://www.jameshardiepros.com/install-and-tech-docs/browseall
you're welcome,

 

[firetruck41]

Do not caulk the **** joints of the siding, it might look good for a few months, but will eventually crack and the paint over the caulk will start to look different and the joint will actually stand out visually, much more than if you don't caulk it. If you drive around neighborhoods that are about 10-15 years old you will be able to see the difference. At least around here, they used to caulk all the **** joints, but then have stopped in the last 10-15 years. Looks much better now.

Definitely do the flashing behind the joint though.

 

[MushCreek]

I put my Hardi on over furring strips for a drainage plane. I believe that that is best practice. The idea is to allow moisture behind the siding to drain and/or evaporate. Supposed to make the paint hold up better. I pre-primed and painted my siding as I put it up. I have three 8' sawhorses, and did all of my cutting and fitting for 8 or ten pieces, painted them, then hung them. That way, if one moves a little, you won't see the primer underneath. I didn't do any caulking.

 

[Jackfre]

I snapped chalk lines and nailed to the studs. I will not use osb.

 

[Deude_Mann]

My house construction was blue foam board over studs, and then Hardie siding, the type that looks like stucco. It has all held up well, no problems. I have not had to do anything except repaint due to the age of the original paint.

The joints between sheets are not caulked.