2 hardiboard construction questions

[FJ and G]

In near future I'm going to design a building made of hardiboard, a type of masonite sheetrock used for tile backing in wet areas; e.g. bathrooms.

I have 2 questions reg. hardiboard.

1. I plan to affix corrugated alluminum (pop cans) to the sides of the hardiboard direct. What type of glue would be good to connect aluminum to rock

2. As for the joints, I'm thinking to first build a framework of treated pine and then, using sheet rock screws, attach the hardiboard to that. Or, perhaps there's a better way?

I've never used hardiboard except for doing turnout bases, but the things that intrigue me in its usage is it's weight (I've had wood structures blow away); and it's imperviousness to moisture and decay.

[Capt Bob Johnson]

Dunno about #1, never tried it.
#2, I don't use a frame, I glue it with exterior grade construction adheasive.

Somewhere way back I put a bunch of info into the forum, but the main gist of it is that I called the manufacturers and told them what I had in mind for a use for the product. I was told that it would be excellent, lasting a number of years if used as is. However, they felt that it would last just about forever if you were to coat it inside and out with some cheepo latex exterior house paint. Then do any decorating paint over that!

[Anonymous]

I'd use construction adhesive, buy it in the tube and just use a scrap piece of wood to trowel it out. I might also help to lighty scuff the aluminum cans a little for extra bite before running them through the crimper.

[ttrigg]

David:

In my limited experience with blue board (which I believe, is what your hardiboard is called out west). Blue board is a "cement" sheet rock ( or plasterboard) for use in and around bath, shower etc. From my limited use of the stuff I would give the following answers.

1) Liquid Nails

2) Blue board is not very stable glues to itself. (At least in my experience) Use an internal frame and "galvanized" or "hot dipped" sheet rock screws. Standard sheet rock screws will rot off in about 3~4 years.

[kstrong]

I used PL Construction adhesive, which is a polyurethane adhesive that comes in a caulk tube. My buildings haven't made it off the workbench yet, but the glue is strong enough, and even with 1/4" material, there's enough meat to hold things together. No braces, just the glue on the edges.

Later,

K

[Capt Bob Johnson]

Tom,
Blueboard is plain old sheet rock with a water resistant treatment.

Hardiboard is a cement/slica sand mix.

No way would I use a gypsum board outdoors!

There are several brands of the cementitious type backer boards, most have some wire or fiber reinforcing in or on them that make them more difficult to get a clean cut!

I have enjoyed working with the Hardiboard. It's made out there in CA, and you should be able to find it in any good supply store like Lowes, Home Depot, or whatever you have out there.

The Hardiboard also comes in a 3' X 5' sheet which is a lot easier to handle than a 4 X 8, let alone a lot lighter due to size difference!

[Anonymous]

QUOTE: Originally posted by Capt Bob Johnson

Tom,
Blueboard is plain old sheet rock with a water resistant treatment.

Hardiboard is a cement/slica sand mix.

No way would I use a gypsum board outdoors!

There are several brands of the cementitious type backer boards, most have some wire or fiber reinforcing in or on them that make them more difficult to get a clean cut!

david,
i've used the above type materials professionally over a number of years and i can tell you they are the most difficult and frustrating materials in all the construction trades.

the cement panels with the nylon netting inside (wonderboard!, hardiboard?) resists any kind of clean cut and crumbles if not buried under tile.

the oil impregnated sheetrock (greenboard!, blueboard?) resists gluing (kind of like your thompsons waterseal fiasco).

tile cement is the glue designed for this stuff (i would go with some of the above advice for your glue because i hate tile cement also).

if you are just going for the weight; why not plaster or stucco, or just a big rock inside to weigh it down, or scratchbuild a palace out of marble.

good luck, -rrick

[Capt Bob Johnson]

Rick,
the Hardiboard does not have that netting in it. I have knife scored it to break and sanded the edge smooth from there with passable results: however if doing something more precise, I use an appropriate blade either in my hand held circular saw or my radial arm saw! Wear a dust mask either way!

[kstrong]

I've been using a mix of the Hardibacker board and a similar product called "Fiberock," which is made by USG--but is not a gypsum product.

Disadvantage - it's not designed for constant contact with moisture, so ground contact is not advised. Atmospheric contact--such as you'd get using it as a wall--will be fine.

Advantage - cuts like butter, no special blades necessary.

I used the Hardibacker board for my bases, as that will serve as a moisture barrier. The walls, then can be built from the Fiberock material.

Later,

K

[Anonymous]

Has anyone tried to use a tile saw to cut hardiboard? If it works, I would think that it should make a smooth cut.
Paul D

[FJ and G]

Paul,

I've used a Skillsaw with a masonry blade to cut hardiboard (as well as backerboard).

Also, I cut hardiboard with a 3" masonry cutting wheel affixed to a $10 edge grinder I picked up from Harbor Freight when they were on sale during the new year. I use the wheel when I'm cutting intricate shapes like those I used for turnout bases. The neat thing about using hardiboard for turnout bases is that one side of the hardiboard has a grid pattern that makes it easier to lay out and align the turnout components that I'm handlaying.

The neighbors know when I'm cutting b/c of the noise and the great amount of dust kicked up in the air in my backyard.

I've also got a tile saw (wet variety that I used when tiling my basement). I haven't tried that but sure it will work. I'm reserving that tool for making mini tiles for structures later on.

[markperr]

What do you use for the dust? Do you use a respirator or just a paper mask? Or do you wet it first?

Mark

[Capt Bob Johnson]

The Hardiboard I use is smooth both sides, I've seen the other, but didn't like it for my applications!