Extending the hearth extension

[Ctwoodtick]

how expensive might it be to have hearth extension extended out about 8 or 9 inches?I’d be hiring a pro for this. I believe it’s a slate of some sort. It’s currently at 18 inches from stove door opening, which is good for this insert. We’re having new hardwood flooring put in within next several months and thought it would be a good time to give myself the leeway to be able to sometime put in a freestanding stove or an insert that is not flush, requiring more hearth in front if door.

 

[Ctwoodtick]

‘This thread (and duplicate) can be deleted. I just read other post about hearth extension and I think it will be way too costly for be to even think about this project.

 

[fire_man]

I'm not sure why it should be so expensive unless you are talking about the entire job to install hardwood flooring. The cost of materials for the extension should not be that bad since its such a small area. I installed an extension just like yours with Hardwood flooring already around it and it was probably less than $250 and that included some tools I bought.

My rule of thumb is the labor costs about the same as the materials for a job like this.

 

[bholler]

I'm not sure why it should be so expensive unless you are talking about the entire job to install hardwood flooring. The cost of materials for the extension should not be that bad since its such a small area. I installed an extension just like yours with Hardwood flooring already around it and it was probably less than $250 and that included some tools I bought.

My rule of thumb is the labor costs about the same as the materials for a job like this.

But did you build it to code by reframing and pouring a new slsb with no combustibles touching the underside of the hearth extension?

 

[fire_man]

I used Micore and met the R value requirments and it was inspected by the town. I never heard of extending the sllsb for a hearth extension.

 

[bholler]

I used Micore and met the R value requirments and it was inspected by the town. I never heard of extending the sllsb for a hearth extension.

If it is a permanent hearth extension in front of a masonry fireplace it needs to be built to code as if it was being used for the fireplace. I see no safety issue as long as you met r value but it doent meet code.

 

[fire_man]

Why does it not meet code if the original fireplace had the proper hearth. All I did was add an extension to meet new requirements for a woodstove which extended further into the room. Why should the slab have been extended to meet code?

 

[bholler]

Why does it not meet code if the original fireplace had the proper hearth. All I did was add an extension to meet new requirements for a woodstove which extended further into the room. Why should the slab have been extended to meet code?

Because it is a permenant hearth extension for your fireplace. By code that hearth extension needs to be on a self supporting slab with no combustibles touching the underside no matter how big it is. Again i see absolutly no safety issue just a code compliance one

 

[fire_man]

I give up trying to make sense of code. I improved the R value further away from my compliant fireplace and now I am not code compliant.

 

[bholler]

I give up trying to make sense of code. I improved the R value further away from my compliant fireplace and now I am not code compliant.

I never said it made sense

 

[spudman99]

Its also code for future reasons. If a future buyer wishes to install a free standing, they would not know what composes the extension. Code ensures that all future users can be comfortable in a common standard and sound installation. So it may not make sense to you, but it may also save a future user from an unexpected problem.

 

[fire_man]

Its also code for future reasons. If a future buyer wishes to install a free standing, they would not know what composes the extension. Code ensures that all future users can be comfortable in a common standard and sound installation. So it may not make sense to you, but it may also save a future user from an unexpected problem.

Your statement implies that any freestanding stove installation needs to meet the requirement that it "be on a self supporting slab with no combustibles touching the underside" which is essentially a hearth with infinite R value. Otherwise, as you claim, any future intallation of a new stove with greater R value specifications potentially puts a future installation at risk of not meeting the higher R value.

Either I missed something from reading years of forums discussing building a hearth with the correct R value or this is a code requirement not often discussed.

 

[bholler]

Your statement implies that any freestanding stove installation needs to meet the requirement that it "be on a self supporting slab with no combustibles touching the underside" which is essentially a hearth with infinite R value. Otherwise, as you claim, any future intallation of a new stove with greater R value specifications potentially puts a future installation at risk of not meeting the higher R value.

Either I missed something from reading years of forums discussing building a hearth with the correct R value or this is a code requirement not often discussed.

A hearth for a freestanding stove is one thing and it only needs to meet stove specs. But a hearthextension for an open fireplace has ots own requirements has its own requirements that must be met.

 

[bholler]

Its also code for future reasons. If a future buyer wishes to install a free standing, they would not know what composes the extension. Code ensures that all future users can be comfortable in a common standard and sound installation. So it may not make sense to you, but it may also save a future user from an unexpected problem.

While your statement makes sense the real reason is incase in the future someone eants to go back to an open fireplace the hearth extension needs to meet requirements for that. You can get around it by using a non permenant hearth pad.

 

[fire_man]

I'm looking at what I believe is the proper code statement and all is says is the Hearth Extension has to be at least 16" in front of a fireplace opening that is less than 6 feet wide and reinforced to carry its own weight. Just because the hearth is extended I don't see why it has to meet the self-supporting requirement. I am sure bholler knows the code but I don't see how it gets interpretted that way.

Maybe this is just a fine point of interpretation that it has to be "readily distinguishable" from the surrounding floor.

 

[bholler]

I'm looking at what I believe is the proper code statement and all is says is the Hearth Extension has to be at least 16" in front of a fireplace opening that is less than 6 feet wide and reinforced to carry its own weight. Just because the hearth is extended I don't see why it has to meet the self-supporting requirement. I am sure bholler knows the code but I don't see how it gets interpretted that way.

Maybe this is just a fine point of interpretation that it has to be "readily distinguishable" from the surrounding floor.

View attachment 226619

Unless that extension is readily distinguishable from the origonal hearth extension it is part of the hearth extension and needs to meet the carry its own weight requirement.