Is there flexibility in clearances?

[mikeathens]

Jim: I understand the point. But in this thread: https://www.hearth.com/talk/threads/11895/

you posted durock specs in a durock manual. If I follow the brochure, it appears that my hearth is fine, using the durock brand - I would just be a bit shy of the minimum hearth extensions. BUT...do the calculations, and that brochure's method of building a hearth won't meet my Hearthstone minimum R-value requirements of 1.2.

 

[JimWalshin845]

Jim: I understand the point. But in this thread: https://www.hearth.com/talk/threads/11895/

you posted durock specs in a durock manual. If I follow the brochure, it appears that my hearth is fine, using the durock brand - I would just be a bit shy of the minimum hearth extensions. BUT...do the calculations, and that brochure's method of building a hearth won't meet my Hearthstone minimum R-value requirements of 1.2.

Then build your hearth to spects that are appropriate for your stove. I wouldn't use Durock for Nuke Plant either. Stoves that are less than 6"s off the floor require different specs.

I just posted the Durock link because they are the only company that are UL listed from what I have been told by the Mods of H dot C and my own investigation.

 

[webbie]

For total discussion sake, it is doubtful that anyone at home will get their hearth as hot as the UL testing does. They use Firebrands, little pieces of oven dried wood - and you can get they have no ash in the ash pan or on the bottom of the stove! The hearth is definitely painted black (to soak heat, as are the walls). Even that all said, the UL standard of approx 95 degrees over ambient temp (say 170 total F degrees) would never even come close to igniting anything! Heck the pipes from a hot water boiler get much hotter than that, and they certainly run right through wood, etc.

But there are other factors also. They don't want standard glues or mortars failing either, and don't want paints melting and flaking off the walls. They want a big margin of safety because they KNOW that jackasses like "US" are going to fudge things once in a while.

So, is close enough good enough? In the case where there is a tiny difference between the specs of the Dura manufacturer and the manual, it probably is. But in the real world, most would treat it like this - if building from scratch they would error in the side of safety and put the extra R value. If it already existed and was really, really close, they (and even inspectors) might let it slide.

 

[DriftWood]

it is doubtful that anyone at home will get their hearth as hot as the UL testing does...Even that all said, the UL standard of approx 95 degrees over ambient temp (say 170 total F degrees) would never even come close to igniting anything! But in the real world, most would treat it like this - if building from scratch they would error in the side of safety and put the extra R value. If it already existed and was really, really close, they (and even inspectors) might let it slide.

Any one who has seen a fire realy take off and start a chimney fire, seen the charred remains of a stove related house fire would agree "error in the side of safety and put the extra R value."

It is possible someone at home will get their hearth as hot as the UL testing does . We all know S*** Happens. I had a log roll out of a fire place and sit there till the smoke alarm sounded at night. The main reason for my stove install and it is over kill and 100% buy the book. +inches in all directions.

https://www.hearth.com/talk/threads/3106/

 

[JimWalshin845]

Something also needs calcification; the photo I posted in this thread is NOT Durock. I do apologize if you constued that. It was 2 pieces of 1/4" board that may be asbestos (one of the BEST insulators known to man).

When redoing our heart it was under the tile that was put down with a mastic adhesive that had failed.

The boards were only nailed down and were not embedded with mortar. The white scorched area under the asbestos underlaymet is a 3/4" fireproof board that is used for commercial practices and that is over a 3/4" plywood.

And yes... when we pried the boards up said "Holy Crappolla"?

 

[rsiros]

There is a slate hearth in my home that I didn't install. My house was built in 1949. What should I expect there to be under the slate, and is it safe for my Hearthstone Homestead to sit on?

 

[Metal]

There is a slate hearth in my home that I didn't install. My house was built in 1949. What should I expect there to be under the slate, and is it safe for my Hearthstone Homestead to sit on?

Only one way to find out, pull it up and see. I am pretty sure codes have changed since 1949 (I don't have copies going back that far). I am guessing the inspector will want to know what's under there though.