Hardie Board, Lath and tar paper

[jongig]

I am putting Ownes Corning cultured stone modules onto my kitchen but I'm unsure of this one step. I've used 1/2 inch Hardie board on the kitchen and am now ready to put the lath on and then the scratch coat.

Should I put tar paper on before the lath? I have seen some use tar paper and some not use it with Hardie board.

Owens Corning modules are not individual stones but small modules that law flat and stack flat onto each other. Kind of like dry stack.

I am leaning toward no tar paper for the one reason and that is that I will not be able to see the screws in the Hardie board as I screw on the lath.

John

 

[bk406]

I just did my fireplace wall with the same stuff!
I skipped the tar paper. I put the lathe on the hardy backer and called it good. I've even seen it installed right over blue board and plaster. No hardy backer or even lathe and it worked just fine. The tar paper serves little function, really.

 

[jongig]

I just did my fireplace wall with the same stuff!
I skipped the tar paper. I put the lathe on the hardy backer and called it good. I've even seen it installed right over blue board and plaster. No hardy backer or even lathe and it worked just fine. The tar paper serves little function, really.

Thanks. That's exactly what my wife said.

When putting the lath and type s mortar mix on when you do your scratch coat did you use any sealers?

John

 

[bk406]

Nope, no sealer.

 

[thadius65]

The OC cultured is excellent stuff. I did an interior fireplace that looks great. I took remaining pieces and they were around my pond for last 7 years. Direct sun, laying horizontal and fully exposed to Central PA weather. Not a loss of color one bit. Highly recommend.

 

[jongig]

The kitchen has been finished for some time now and last year we had a good time using it. I now have a question about covering it. I covered it for the winter but covering it in the summer is a pain.

I was able to seal much of it but the gas grill has areas where water can still get in and I don't know if I should care. The underneath is Trex decking and water can get out but I'm just not sure if I should care or not.

 

[rexc]

IMO, tar paper(felt) should go on before the hardie backer...assuming the structure is wood. yes the fasteners will penetrate it, but not really an issue on vertical surfaces same as tiled shower walls...

 

[jongig]

I used steel framing, then hardie board, then tar paper, then steel mesh. I then did a scratch coat. Finally I put on the cultured stone. From talking to a mason I get the idea that you want to keep moisture from getting into or through the Hardie board which is what the tar paper will prevent.
I'm very concerned about moisture and I've watched the inside of the unit which sits in the weather. So far so good.