R value

[sprawlnstall]

I recently built a hearth floor pad and was hoping someone could tell me the R value. The build is as follows.

1. 2x4 Base (54 inch by 54inch

2. 1/2 ply wood

3. 1/2 in Durock Cement Board

4. Heavy coat of motar

5. 1/4 inch ceramic tile.

Also I'm a little nervous after looking at the tiles I used. According to menards they have a breaking weight of 275 pounds. I made sure to evenly apply the motar to ensure a flat surface.

Thoughts?

 

[Brucek1$]

You have about a 0.41-0.5 r value there. 1/2 durock is .39 and tile is about .020 not sure what the motar gives. On the weight for the tile kinda depends how heavy your stove is gonna be, but as long as it was laid right with no voids you should be fine

 

[Simonkenton]

54 x 54 inch base of 2x4s. How many 2x4 joists did you run? What is the distance between the 2x4s?

 

[sprawlnstall]

54 x 54 inch base of 2x4s. How many 2x4 joists did you run? What is the distance between the 2x4s?

Plenty of support 16 inches on center, added more support with 2x4 in the opposite direction, looks odd from underneath but will not be seen. Was more concerned with the tile cracking

 

[edyit]

(broken link removed)

best link ever to help figure out R values in hearths

 

[sprawlnstall]

Would it defeat the purpose to put a piece of plywood and mineral board on the bottom?

 

[begreen]

The tile should be ok

Would it defeat the purpose to put a piece of plywood and mineral board on the bottom?

Nothing really gained by doing that. What stove is for this and what is the hearth protection requirement?

If it's a decent quality tile then it should be ok. Porcelain tile is good.

 

[Simonkenton]

I think your tile will be ok. You have a very sturdy hearth.

 

[sprawlnstall]

The tile should be ok

Nothing really gained by doing that. What stove is for this and what is the hearth protection requirement?

If it's a decent quality tile then it should be ok. Porcelain tile is good.

Not quite sure on the stove. I was hoping to get the R value to 1.5 to keep all stove options open.

 

[begreen]

Not quite sure on the stove. I was hoping to get the R value to 1.5 to keep all stove options open.

The hearth as built is ember protection only with an R value of about .40. Fortunately there are many stoves that will work with this requirement.

 

[sprawlnstall]

The hearth as built is ember protection only with an R value of about .40. Fortunately there are many stoves that will work with this requirement.

Englander 30 NC requires 1.5 R value I believe.

 

[begreen]

That's correct. Their 50 SSW01 (Madison) will work with an ember protection only hearth. So will the Drolet Baltic II or HT2000.