We are planning construction of a garden shed to store garden tractor, yard tools, and "stuff" (and regain use of my garage shop). We are considering Smart Siding, Hardi Panel and T-11 (T1-11). Like the looks of T-11 but have been unable to find pressure treated siding used on some factory built buildings.
The Hardi panel looks good but their installation instructions require a moisture barrier. This is a utility building and the siding will also serve as sheeting. No interior finish. Will the cement fiber panel hold up to long term use without sheeting and moisture barrier? I have used a product similar to Smart and the building looks good after 25 years but there is concern with Hardi.
I put that stuff on the shed I built, 10 years ago. I nailed in directly to the 2x4 framing with nothing else on the inside or outside. I never even painted the exterior.
It's the same today, physically and cosmetically, as the day I installed it, except for some staining from mud and grass on the outside from weed-eating and rain splash.
I would not use Hardi without sheathing. Never used SmartSide, though that seems like a good product. Treated T-1-11 is available around here, but I don't recall if it was a LP, GP or Weyerhauser product. Call around and ask who stocks treated plywood siding. The manufacturers are trying to brand their stuff to differentiate theirs from others, so asking for T1-11, while technically correct, might be confusing some of the younger guys.
Why? Unless the stuff has drastically changed in 10 years, you don't need to be over sheathing for a shed. The stuff on my shed is about the thickness and strength of 1/4 plywood, probably a bit stronger and *definitely* much more stable than plywood or OSB sheathing.
While the 2009 IRC does allow direct attachement, I rarely ignore the manufacturer's instructions. Whether it's a house or a shed, if it fails it ain't good.
Shed walls generally take more abuse than a house's walls, stuff is banged up against the walls, etc. Wind and other natural acts (unnatural acts...?) don't differentiate between a residence and a storage building. They're equal opportunity destroyers. That's not necessarily a big problem, depending on where the shed is, and it can be dealt with by installing let-in bracing (old school, but fast enough and it looks really cool), or by using metal strapping on the diagonal in the corners. Like this (bottom left corner):
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as Ron didn't mention where he is, it would be foolish to sell him on an idea that might not work in his area.
You are speaking from a "But that's how I did it and it's fine!" view point. I'm not arguing your personal experience, but standard construction, and particularly the manufacturer's instructions, probably shouldn't be ignored for little reason. I've seen more than a few fiber cement installations that suffered from elephantiasis due to inattention to detail. Frankly I'm surprised that your shed has held up without paint (also no caulk?), as required by the manufacturer, for so long. Perhaps you're one of the lucky ones, but I tend to doubt if you hit 00 on the roulette wheel that you'd tell everyone to bet 00 every time, right?
Ron also said he liked the looks of T1-11, so I'd think that should count for something, no? Plywood siding goes up faster, is cheaper, structurally stronger and looks just fine. So where's the problem?
Whichever siding you use, I would recommend installing a moisture barrier. Two rolls of felt won't break you. Also, build it with walls at least 10' high, i.e., for some attic space. Exterior sheeting is 8', so put a 2' skirt at the bottom, with a drip edge between the skirt and the higher full sheet/panel... see pic. If the bottom ever rots or gets damaged, all you'll have to replace is the bottom skirt section.... not have to mess with a full sheet/panel. If applicable, cut the skirt upper and lower edges at 30=B0, as with the lower edge of the upper full sheet. Screw the skirt onto the framing, easier to remove, if need be. One of my garages has had untreated T1-11 for 20 yrs.... still in good shape. Prior to installing the skirt, I primed and painted the 30=B0 cuts and about 10" (a paint roller width) up the back side. 3/4" nap roller for the rough T1-11, hand brush it smooth... goes faster than you think. Caulk the butting edges of each sheet. Caulk the seams/joints of your drip edge/ sheeting.
The bottom edge of the skirt, cut at 30=B0, doesn't allow water wicking across an otherwise flat bottom and up the back side. A 12" galvanized strip, behind the skirt and slightly lower than the bottom edge, will help keep out any moisture, also... but I'm not sure of your foundation for warranting this gal. strip.
But as Ron didn't mention where he is, it would be foolish to sell him
I think you're trying way over engineer a shed. Everything I've seen on their site speaks about residential construction, not a storage shed.
Again, why are you bringing up manufacturer's instructions that relate to residential installations? Why would I want caulk on a shed? If water runs off, that's enough to keep my stuff dry. In any shed, unless it has HVAC, the temperature and humidity is the same on the inside as the outside. I actually like some airflow in and out of a shed to keep it from turning into a greenhouse in the summer. This can be accomplished with open eaves.
I'm not lucky. Nor are the thousands of other people who put these up as kits from 84 lumber.
The Hardi Panel I put up looks just like T1-11.
I never said there was a problem with plywood. I said it wasn't necessary under the Hardiboard. If you're going to put up plywood, just put up T1-11 and have it be structural. If you're going to put up Hardi... for a shed... you don't need plywood, too.
According to the directions, sheathing is not required for Hardi Panel. However they do stress using a moisture barrier. So at a minimum, no sheathing but I would use a moisture barrier. Then if the product does fail, then you would be able to make claim on the warranty. If it were me, I would use sheathing just to give it more rigidity, a moisture barrier, and caulk the seams as well. Though it is up to you.
If you're worried about a warranty, I would call the company and make sure they will honor it on a shed. I'm fairly certain the moisture barrier has nothing to with protecting the cement board and everything to do with the intended purpose of a moisture barrier on a residence, regardless of the siding material used.
Unless you're going to be heating & cooling your lawn tractor and shovels, there's no need for a moisture barrier. In fact (as I wrote in another post) I would go so far as to have open eaves on the overhang (if you have them) or some sort of venting on each end of the roof peaks, to allow for some air flow to prevent a greenhouse effect.
If this shed will see the kind of abuse mine does I'd use sheathing... it will prevent busting the siding if there are errant impacts from the inside. From my experience with the siding, I think it would hold up to moderate impacts from the outside because the studs would support it pretty well if on 16" centers.
Since there is no insulation or heat or interior drywall the moisture barrier could probably be ignored... there would be some risk of wind driven rain penetration at joints but with the 1 1/4" lap leaks at the laps would be minimal. It will dry...
Maybe I got the super-uber-strength Hardiboard or something, but this stuff is as strong as your typical 3 or 4 ply low grade 1/4" plywood. I would put in up against 1/4" ply on a hammer test, any day.
I haven't experienced that, although it makes me curious enough to do some experimenting, next time I'm out there. I would think its rigidity would help in that department, however. I do have plenty of heavy items leaned up against it and the mower gets pushed against it fairly hard every time I put her away.
The risk goes up if it's wide and blind nailed... I"ve got a lot of heavy stuff in my shed, like digging bars, buckets of lead, etc. that would bust the siding off with no problem if it fell against the siding...
I know 1/2" is standard, but I was using equivalent size for comparison. I might even put up 1/4" Hardi against some of the horrible 7/16" 3 ply I see at Home Depot and Lowes.
3/4" sheathing, imo, would be waaaaay overkill. :-)
I've used 3/4 a few times... like when 1/4 fiber board is on other parts of the house and when I need to nail into the sheathing for trim and such when there are no studs in the vicinity. An example of the later is putting 4" trim around windows and needing to nail the Hardie Plank siding to something. 3/4 is also good in hurricane areas!
Is the siding going to be in ground contact? If not you don't need pressure treated. Paint all exposed surfaces (that's top, bottom, edges, and outward-face) before you put it up, use proper Z-flashing properly gapped along the top, and keep it painted and it should last longer than you will.
The moisture barrier is not there to protect the hardi-panel, it's there to protect the structure behind it. Hardi-panel is much like concrete-- it can hold and pass a remarkable amount of water. Having structure in contact with it with no moisture barrier can result in the edge of the structure in contact with the hardi-panel being kept damp and rotting. Since it's covered by the hardi-panel you won't be able to tell by inspection that it's rotting and your first notice may be when the shed falls down.
Note that you can combine hardi-plank and t1-11 to good effect--if the shed sits on grade the lower edge of the t1-11 will be closer to the ground than is desirable--keep it painted and it will be fine but you have to keep on top of it. If instead you put a foot or so of hardi- plank at the bottom with aluminum flashing behind it, then a z-flashing and t1-11 above, you'll end up with a pretty durable installation that doesn't need much maintenance.
Absolutely will hold up. Like most cement or brick prioducts Hardi products are porus and do not fit together tightly enough to prevent water from blowing in through the bottom of the panels or joints. The moisture barrier is to protect the contents not the siding.
I have used the Hardi "planks" on my home and on my shed. I strongly suggest you do some cross bracing of the walls and not rely on the Hardi or any product of similar nature to ad structural strength of your shed. Hardi prioducts are a strong siding that lasts many years but if the wall wiggles the fantener holes in the product will wollow out. Use this type siding to keep the elements out and not to add strength to the structure.
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