extending a hearth

I want to purchase an jotul oslo f500 but my existing hearth is only 48x48 inches. Is there a way you can buy various widths of fireproof material that would "attach" to the existing hearth to make up the extra width necessary for this stove? thank you.

 

The easy answer..... maybe. Some specifics might help someone help you. Can't be much more vague than the original post.

 

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Stove Boards & Hearth Pads: The #1 Stove Board Dealer (efireplacestore.com)
You will need to know what R value your stove requires...

 

This is what I know. The stove literature says I need an R value of 1.6. The existing hearth is made of 1" cut granite laying on top of 0.4 inch of what I called when it was built in 1985 "asbestos board". Not really sure what it's makeup is.! I still have a large chunk of it left over that I can use. This is all on top of a 5/8" plywood subfloor. I need to extend the hearth out about 6 inches. Sorry to be vague, but the only real given is a R value of 1.6.

 

Sounds like the existing hearth is inadequate for R 1.6 too...and you have an "unknown" R value on the existing insulation (unless you can find some hard data on it) and that granite is near zero, so...
I think I'd just start over so that you know what you are dealing with for sure...Micore 300 is R 1.03 per 1/2", so two layers of that, and then whatever noncombustible surface you want to put over it (stone, tile, steel plate, etc.)

 

I hate R requirements for hearths. I think it is the result of poor engineering. They all should be ember protection only. Some very good brands still have these ancient hearth insulation requirements so if you want their stove you need to screw around with the legit insulation requirements.

There are several materials that you can use to get to R1.6. A huge stack of cement board is one.

 

Here's a previous thread that starts out with the chart of materials and R value per inch.

R values on a hearth build?

So for example with cement board if would take 5- 1/2" sheets, 2.5" total, to get to R1.6.

 

Sounds like it's not too late to choose a different stove.

 

I wonder if the insulation material has to be non combustible.

 

Pictures would be very helpful. Anyway you could post a few? Thanks!

 

My Lopi didn't require a pad with a R value, just had to be non flammable. So had a metal fabrication business make one out of 1/8" steel plate and powder coated. Was only $300 with tax.