Hardie Board Siding?

[ultrarunner]

Acceptable to go right over wood siding with Hardie Board?

Is a adding a vapor barrier or felt recommended?

60 year old wood siding just doesn’t take paint well in deep snow country and looking for a solution if even just for the weather side.

I’ve never worked with cement fiber boards… only stucco, wood, brick and non asbestos tile siding.

 

[HawkinsHollow]

Hmmm, excellent question, i have never put it directly over old wooden lap siding. The main issue I could see with that is inconsistent surface to nail to. I feel like the angle of the existing lap siding would throw off the lapping of the new hardie. Furring strips might be a good idea in this case. I am sure someone that has done this will be along shortly to chime in. Good luck.

 

[EddieWalker]

I've done it a few times on older houses with wood lap siding that is similar to what's in the picture.

Hardie's biggest issue is that it's brittle. It needs a wood backing. OSB or plywood is the most common because it's the cheapest, fastest and easiest to install on new construction. Having thicker wood is a plus.

I've read that you should never double your vapor barrier with something between it. Most of that deals with insulation. In my opinion, if there is a vapor barrier under the wood already, it's not significant enough to not install house wrap over the wood siding.

I clean up the existing siding and smooth out any areas that might be sticking out. I want the Hardie to be flat against the wood. I go ever every board to make sure it's tight. A lot of them are installed with finish nails, and they like to work their way out. I remove loose nails and install screws.

I haven't checked the Hardie website lately, so it's something you should do before installing it. They have instructions on how to do it. I use a coil roofing gun with 1 3/4 inch nails that I put in every foot or so. I think Hardie want's them on every stud, but that's almost impossible to do, so I try to hit a stud where I can, but I'm not too worried if I just hit OSB.

The big issue is the nail head must not damage the Hardie. They want it snug, or even almost loose. Setting the depth on the nail gun means it's strong enough for a stud, but then it damages the Hardie if you only hit OSB. In your case, it will be a lot easier to set the depth on the nail gun since it's all solid wood.

Home Depot sells Hardie blades. They have a small one that's cheaper, and a 7 1/4 inch blade that's a lot more money. The big blade lasts forever, but it's impossible to cut straight with. I don't get it, but it's the biggest waste of money ever. I just buy the small blades now. I can do an entire house with a small bade if there isn't a lot of trim. I just use my 18volt Makita cordless saw to cut everything.

Smart Siding looks similar to Hardie when installed. It has a lot of good qualities, and it's a lot easier to install. I use a sealer primer on everything I cut before I install it. For my house, I use Hardie. For clients, I let them decide, or if I'm matching what's already on the house, then that's what I use. The finish look is always the most important for the client, and I'm comfortable with both products being good enough to last and make my clients happy.

 

[paulsharvey]

Well, we would need more info. Is that old lap siding nailed to a plywood/osb sheathing, or was it nailed to studs? If no sheathing, I would be concerned about just the siding holding the hardi. Hardi is heavy; and generally installed with short nails, although longer are used on the trim.

 

[EddieWalker]

I use three inch deck screws for Hardie Trim. I tried a framing nail gun, but they never went in all the way and I hated beating them in with a hammer right next to a window.

 

[ultrarunner]

The wood siding is nailed direct to studs. No house wrap or foil face insulation.

The 2x4 stud cavity has standard craft faced insulation with the paper side on the interior.

Summer cabin built 1961 and not unusual for snow to be roof height in heavy snow years.

I will need to check for cupping but easy to replace any cupped boards… this is how I know what’s behind the siding.

I’ve done several small additions in the Bay Area where home had cement asbestos siding… the cement asbestos no longer available but used same appearing without asbestos and it nailed directly over the old wood siding… 40 years and my one double coat of paint still excellent.

I’m hoping not to pull off all the old siding and trigger the entire permit process…

A few cabins have aluminum siding but it always appears dented from snow/ice that rolls up against it…

If I scrape, prime and paint after replacing damage boards it will look ok for 3 or 4 years maybe.

 

[ultrarunner]

Another view

 

[ultrarunner]

12x12x24 cement fiber might be my easiest route.

 

[2manyrocks]

12x12x24 cement fiber might be my easiest route.

View attachment 3651622

About 3x more expensive. Paint may last longer, but still intended to be painted, too.

If the siding is dry and in good condition, why wouldnt you install tar paper over it, and then nail on Hardie? The tar paper is to protect the substrate from water penetration.

 

[ultrarunner]

I’ve had really good service from the 12x12x24 tiles I painted once in 1985…

Only downside is replacing 4 at a rent house due to bicycle and garbage can impact but easily done.

They are also lighter in weight…

 

[ponytug]

It would be a good solution, but decide whether you want planks or panels, and if panels, whether you want the 4x8/4x10 panels. If you go the plank route, I would recommend the accessories that hold the planks in place while nailing. They speed things up considerably.

James Hardie requires vapor barrier below it. If you do plywood, then vapor barrier, then panel, the barrier needs to be the type with a ridged or beaded surface that lets water drain down.

Try getting the Heat Zone 5 or 10 technical bulletin #19, and look at the accept ways of installation. (Check your location against their map for Heat Zone.)

There's a nice couple of Matt Resinger videos on YouTube on how to do them.

All the best,

Peter

 

[2manyrocks]

The existing siding looks like tongue and groove. With the joint being horizontal, particular care needs to given to not allowing moisture to become trapped.

 

[ultrarunner]

It would be a good solution, but decide whether you want planks or panels, and if panels, whether you want the 4x8/4x10 panels. If you go the plank route, I would recommend the accessories that hold the planks in place while nailing. They speed things up considerably.

James Hardie requires vapor barrier below it. If you do plywood, then vapor barrier, then panel, the barrier needs to be the type with a ridged or beaded surface that lets water drain down.

Try getting the Heat Zone 5 or 10 technical bulletin #19, and look at the accept ways of installation. (Check your location against their map for Heat Zone.)

There's a nice couple of Matt Resinger videos on YouTube on how to do them.

All the best,

Peter

Thank You… location Tahoe.

 

[JJT]

I'd give paint one more try, unless you have a considerable amount of wood to replace. Good prep and two coats of quality paint should last for 10 years.

 

[ultrarunner]

The existing is 9 years old done after several days of hand scraping, feathering and prime with 89 square feet of boards replaced below kitchen window where the valley drains.

The other side not on the weather exposure side looks good… it’s just this side that gets all the exposure.

My grandparents farm has the entire wall on the exposure side covered with 12x12x24 tiles installed right after WWII and still good…

 

[2manyrocks]

I would put my time and energy into more durable siding instead of having to face this again in 5-10 years.

 

[Rustyiron]

^^^ That was asbestos and no more dangerous than hardy BUT back then they cut them with a guillotine type shear. Saw cutting requires the same precautions for inhalation.
LP "Smart Side" blows away Hardie's so called fibre "cement" siding.
The big players have moved to LP Smartside from hardy and their big book of excuses as far as them covering anything in their warranty.

 

[ultrarunner]

If I use tile I should be able to bring everything needed by car… which is good since the service truck is laid up.

 

[ultrarunner]

^^^ That was asbestos and no more dangerous than hardy BUT back then they cut them with a guillotine type shear. Saw cutting requires the same precautions for inhalation.
LP "Smart Side" blows away Hardie's so called fibre "cement" siding.
The big players have moved to LP Smartside from hardy and their big book of excuses as far as them covering anything in their warranty.

I bought a guillotine with nail hole punch years ago for $20 at an estate sale after just finishing a job… it’s been tucked away 35 years someplace and never had occasion to use.

 

[not2old]

Home Depot sells Hardie blades. They have a small one that's cheaper, and a 7 1/4 inch blade that's a lot more money. The big blade lasts forever, but it's impossible to cut straight with. I don't get it, but it's the biggest waste of money ever. I just buy the small blades now. I can do an entire house with a small bade if there isn't a lot of trim. I just use my 18volt Makita cordless saw to cut everything.


I wasn't aware of saw blades for this when I did the siding on my shop and used a guillotine to cut it, always putting the cut end where it would be covered by smartwood trim where possible. When cutting the pieces that butted up ,against the aluminum soffit on the gable ends, I clamped a piece of angle iron on the line as a guide and made the cut with an angle grinder and a thin metal cutting blade or a diamond blade, I don't remember which. The result was a perfectly straight cut that looked like a factory finish.