Tips on Nailing Fiber Cement Boards

[Perry Holbrook]

New neighbor is building a nice house next door. Exterior walls and all the trim are fiber cement sheeting and 1x's. He gifted me about $1K worth of scraps. Got plans for lots of bird houses and other outdoor type projects. Just started playing with it today. It cuts fine with the correct blade. I cut 4 pieces of 1x4's, 12" long and clamped them up for the sides of a small box.

To fasten the corners going thru the face of one board into the end grain of the other, I tried:

Drilling a shallow pilot hole in the face and hammer and nail -- both pieces split

Drilling a thru hole in the face and hammer and nail --- end grain split badly

Drilling a thru hole in the face and half way into the end grain hammer and nail into the end grain --- end grain split

Drilling a thru hole in the face and half way into the end grain then a deck screw that only went into about 1/2" undrilled -- end grain split

I don't have a masonry bit smaller than 1/8" so I can't drill a complete pilot hole for the screw, but I'm guessing it would split anyway.

Got frustrated and quit for today

I've got a nail gun that shoots 15 ga finish nails (galvanized). Going to try that tomorrow. If that doesn't work, anybody got a trick for working with this stuff?

Thanks

[Dave Zellers]

I would use a bead of adhesive made for cement board and your nail gun to hold things together until it sets. Although I think an 18ga brad might be better. The glue will will do the job so anything that holds your box till it dries will work. Rubber bands, string, clamps, etc

[Bill Dufour]

I used a coil siding gun.
BilL D

[roger wiegand]

I'm confused about end grain, I didn't think fiber cement board has grain-- are we talking something like Hardie board? If so, I'd put a wood nailing block in the corner and only nail through the thin dimension, predrilling if it's close to the edge . I doubt that material will hold nails or screws in any event, even if it doesn't split.

[Cameron Wood]

Place all the pieces in the trash can and walk away, knowing that you gave it a try.
Things could possibly be made with just glue, but the dust from cutting is nasty. I would never make any saw cuts inside, and use mainly shears, avoiding all sawing if possible.
Generally, the material will likely break from any fastener closer than 3/4" from an edge.

[Perry Holbrook]

I'm confused about end grain, I didn't think fiber cement board has grain-- are we talking something like Hardie board? If so, I'd put a wood nailing block in the corner and only nail through the thin dimension, predrilling if it's close to the edge . I doubt that material will hold nails or screws in any event, even if it doesn't split.

While I have a stack of sheet stock 5/16" thick up to 10 ft long smooth on both sides, I'm talking about boards made out of fiber cement that have a cross section of 1"x 3.5",5.5" &7.5" (think of a full 4/4 oak board that weighs about 4 times heavier). When I say end grain, I know cement doesn't have a grain, but I don't know a better description of the end cut off.
It just splits so easy when you drive a fastener into the end of the board.

I'll try the glue, just thought it needed some mechanical support as well.

[Dave Zellers]

I'll try the glue, just thought it needed some mechanical support as well.

Only to hold things together until the adhesive sets. Brush or blow off any dust from cutting and Bob's your uncle.

[Perry Holbrook]

Only to hold things together until the adhesive sets. Brush or blow off any dust from cutting and Bob's your uncle.

Dave, do you have a favorite adhesive for this?

[Dave Zellers]

Dave, do you have a favorite adhesive for this?

No because I don't do it, I just know it will work. Ask at your favorite hardware store for cement board adhesive.
Something like this- https://www.amazon.com/Loctite-Polyurethane-Construction-Cartridge-1390595/dp/B001E3VQBE/?th=1

You may find that just the tacky glue will be enough to hold things together until it sets.

[Jim Becker]

This stuff is difficult to work with in large pieces and so much more so on small projects. I'd consider using it for like the "roof" of bird houses and other outdoor things while using more easily worked materials for the structure. Cement board products are not very "strong", are quite brittle and are largely designed for cladding due to the fire resistance it brings. Folks installing it for siding have to be really careful about supporting it while they get it up on the building to nail in place...it will crack into pieces just under its own weight if it starts to "bend".