Hardi board/fiber cement install question - Contractor Talk - Professional Construction and Remodeling Forum

enforcer · 11-04-2008, 09:02 AM

this product is new to me as far as installation goes.i am actually going to install it on an investment property so if we mess up,we can just re do it. my question is this;does fiber cement expand and contract like vinyl siding?
i would imagine it gets nailed in all the way using a nail gun?
do any of you guys use insulation board under the fiber cement?
before you come down on me for starting a project i am not familiar with,its my property so what better way to learn!

Forry · 11-04-2008, 10:38 AM

1/8" gaps between planks and caulk. (I cheat it down a little so it looks better, but 1/8" is what the manu. calls for) Nail it tight, and no ins. underneath. 7d siding nails gun nailed work best for me, never staple it. Roof nails work ok, but sometimes if you shoot too low, you see the nail head.

Grumpy · 11-05-2008, 10:27 AM

Don't forget to slide some metal or felt behind the gaps before caulking incase the caulk ever fails.

Nail guns are fine if it's shooting a small shank ring nail. Hot dipped galvanized are good.

Don't use insulation IMO. It'll look too to wavy.

Go get the installation manual from James Hardie and Certainteed Weatherboards.

Tenn sider · 11-07-2008, 05:53 PM

Fiber cement does expand and contract but not like vinyl at all only somewhere less tha 1/8" I agree, deffinately put a piece of coilstock behind the seam leave1/16" to 1/8" between boards. When we use prepainted fiber cement we do not use caulk between joints just a 4" piece of coil stock, you can not see it when done. We had problems with the color matched caulk James Hardie supplied not matching up just right especially after a few months. If you are using a primed board product you can caulk with a good siliconized acrylic caulk then paint over. Hardie and certainteed are now requiring a full head ring shank hot dipped galvanized nail that has to be 1 1/4" into a stud. We use a duofast gun specifically for siding with a 1 7/8" nail. The guns and nails are spendy! We do sometimes use a ridgid fanfold insulation under fiber cement and have no problem with waves as long as the substrate is good and flat.
Go to certainteed fiber cement they have a good instruction manual
C ya

LetItBeLEED · 06-09-2009, 10:50 PM

I use the woodgrained textured boards so that caulked butt joints are less noticeable. To do that, I brush the caulk in line with the wood grain using a nylon bristle brush. After painting, they are barely noticeable. I try to blindnail but on sides facing the usual direction of storm winds, unless those places are particularly visible, I will often nail the bottom edges also. I shoot hot dipped galvanized nails with my framing gun (using a soft tip attachment to keep from scuffing the boards). I keep the pressure low in the gun. Sometimes nail heads stick up and I have to finish them with the hammer, but that's better than overshooting and damaging the material.

**Teetorbilt** · 06-09-2009, 11:00 PM

Great product with the exception that you should nail 1" from the edge. That makes it a little tough to hit a stud @ 1-3/4".

rojigga · 06-10-2009, 12:52 AM

Don't leave a gap. Go tight. Gap will form no matter how tight.

nEighter · 06-10-2009, 01:21 AM

and use elastomeric caulking not siliconized.

LetItBeLEED · 06-10-2009, 05:42 AM

Good point about corners, Teeterbilt. For the ends of the boards I either pre drill and hammer manually, or else I skip the nails altogether and rely on clips to form the butt joint without any fasteners

Ranzan · 06-10-2009, 07:58 AM

Field joints should be light to moderate contact as Rojigga said they will serperate a bit over time

Sidingmaster · 06-10-2009, 09:30 AM

Quote:

Originally Posted by rojigga

Don't leave a gap. Go tight. Gap will form no matter how tight.

Not good advice, when the fiber cement expands from moisture it will bow the seams out , look horrible and void the warranty

thesidingpro · 06-10-2009, 12:46 PM

Light contact on field joints has worked for me from day one. I would never caulk the field joints. 5 years later the caulk looks horrible.

I've never had a problem with bulging field joints. Most likely the ones that do are installing them to tight in the first place.

rojigga · 06-10-2009, 01:20 PM

Quote:

Originally Posted by Sidingmaster

Not good advice, when the fiber cement expands from moisture it will bow the seams out , look horrible and void the warranty

In my experience the moisture content is at its highest when being installed. I have never seen this bulging over time unless like thesidingpro mentioned the install was originally too tight to begin with. Like I said, I have only ever seen hardie shrink; if it has expanded the siding shows no ill-effect from it.

**Teetorbilt** · 06-10-2009, 07:47 PM

LetItBe, we have to follow to the letter to meet Miami-Dade High Velocity Wind Code.

On my test house, mine, I replaced the gable ends (the most common job around here). I cut to fit, primed all sides with BM oil-based primer, installed w/ construction adhesive leaving a 1/16" gap, filled the gaps with BM's best exterior caulk and painted 2 coats of BM's best exterior paint.

My house faces east, the south side gets FL sun all year and the north side none at all. This was done after Francis, son of Ivan and Jeanne hit in 2004. Wilma tested it the following year, it still looks great.

I continue to install this way with zero complaints.

burhop · 06-16-2009, 09:20 AM

can you tell me the going rate for installation of hardiplank

willworkforbeer · 06-16-2009, 09:25 AM

Quote:

Originally Posted by burhop

can you tell me the going rate for installation of hardiplank

And this thread was starting out so nicely...

LetItBeLEED · 06-16-2009, 09:43 AM

Quote:

Originally Posted by Teetorbilt

LetItBe, we have to follow to the letter to meet Miami-Dade High Velocity Wind Code.

.... installed w/ construction adhesive.....

Are we talking cement boards or sheets? This is the first I've heard of using any kind of glue with cement board lap siding. Please tell more.

tccoggs · 07-02-2009, 02:31 AM

Quote:

Originally Posted by rojigga

In my experience the moisture content is at its highest when being installed. I have never seen this bulging over time unless like thesidingpro mentioned the install was originally too tight to begin with. Like I said, I have only ever seen hardie shrink; if it has expanded the siding shows no ill-effect from it.

I have to say I agree. Also be aware of the tempature when you install. If installing in July in the sun, but the joints tight, the material will be at max dimension and will shrink in the winter months. I put 23 square of 6 1/4 on my house and the joints still look great. I places slip sheet behind and caulked with Geocel 2300 color match. The south side of the house still looks like the day I installed it.