A couple of brick hearth questions - mortar?

[joecool85]

We finally have the chimney all installed and ready to go. Now I need to make my hearth. We have 4" x 8" concrete pavers we are using. The hearth is going to be 42" x 38" and I have a 3/4" piece of plywood laid down already and it is shimmed to level. It is screwed down to the floor. On top of that I have 2 sheets of 1/2" hardibacker 500 giving me .34 R so far. The concrete pavers are 1.75" tall so that should give me .166 R. Total that is .506 R and I need .5 R, so that's just enough.

Now, I've never done masonry. When I lay down my pavers, do I put mortar underneath them? If so, how much? There's going to be between 1/4" and 1/2" gap between the bricks depending on where in the pattern you are looking at (I've laid them dry to check). If I had even 1/4" of mortar underneath that would bring my hearth up to .556 R.

All R values are according to http://chimneysweeponline.com/horvalue.htm

Thanks guys.

**edit**

I also put a steel "lolly column" support in my basement under the hearth area "just in case" since I will be adding a lot of weight there.

 

[joecool85]

Looks like I'll be using 1/4" of mortar then lay the pavers. The folks over at arboristsite.com were helpful on this topic.

 

[pen]

With tile, the thickness of the mortar is more important because if you go too thick it will ooze up inbetween your tiles and not leave you room for grout.

W/ pavers which are so much thicker, you can really get away w/ a lot more.

Sorry I didn't see this sooner. I lost it in the shuffle. The lack of a reply certainly wasn't intentional.

pen

 

[joecool85]

With tile, the thickness of the mortar is more important because if you go too thick it will ooze up inbetween your tiles and not leave you room for grout.

W/ pavers which are so much thicker, you can really get away w/ a lot more.

Sorry I didn't see this sooner. I lost it in the shuffle. The lack of a reply certainly wasn't intentional.

pen

I figured as much, it's been busy in here. I took no offense to it. I'll probably go with 1/4" because it'll be easy to do with a grooved trowel.