How wide should my border be in order to be safe?

[EatenByLimestone]

I have a raised hearth where the top is 2" above the floor I'm installing. How wide should the border be for it to be safe. I'm afraid if it's too steep somebody will trip and plant their face on the hot wood stove. Are there any codes regarding this?

Matt

 

[Gooserider]

I have a raised hearth where the top is 2" above the floor I'm installing. How wide should the border be for it to be safe. I'm afraid if it's too steep somebody will trip and plant their face on the hot wood stove. Are there any codes regarding this?

Matt

The manual for your stove will specify the minimum size for the hearth pad, doesn't matter if it's raised or not. General rule of thumb is 16" minimum in front of loading doors to catch falling embers (18" in Canada, their embers can jump further :gulp: ) other dimensions to match your stove's CTC numbers, but that is just a rough guess. See your manual for exact answers. I would be tempted to go over width, or at least use the Canadian spec for the area in front of the doors, but then I'm paranoid.

Bear in mind that larger is not a danger (other than the face plant potential you mention) and an oversize, and over-R value stove may offer better options if you think you might ever want to go to a bigger stove.

Gooserider

 

[EatenByLimestone]

Whoops, maybe I wasn't specific enough. My hearth is 6' by 7', so the actual size isn't the problem. Now that I put the new floor in, I want to put a border/trim out around the hearth. I'm worried about the trip hazard. Should I go out 4" and then up 2, or what?

Matt

 

[Gooserider]

I don't know if there is an official "spec" on how to do this, I know our brick hearth just goes straight up from the floor surface. My gut instinct says that going straight up is better than having any kind of "toe trap" ledge, but I don't know if there is any sort of standard about it. Another thing that is probably not code specified, but IMHO it's a good idea if the floor and the hearth are a different visibly contrasting color / pattern so that you have a definite visual clue to anyone walking in the area that there is a step change to negotiate... (If it was a factory, OSHA would be requiring that ugly yellow / black striped tape on the edge - I wouldn't go that far, but they have the right idea...)

Gooserider

 

[stoveguy2esw]

there is no standard set that im aware of as long as the minimum clearances are satisfied, with a hearth that large obviously there are no clearance problems just a worry about stumbling in the dark i guess, and there are no "bumper pads" available for woodstoves i guess the only things i can think of is possible a hearth fence (usually used with wee ones (kids)) or maybe installing some lighted strips around the edge of the hearth to light the way for wayward toes. other than that , im drawing a blank

 

[EatenByLimestone]

Cool. Thankya guys.

The yellow and black tape would probably do wonders for resale!

Matt

 

[Corie]

Little LED strips around the hearth would be pretty darn cool looking. They could even change color to reflect the stove temperature.

 

[bcnu]

My hearth area is 3x6 and I'm also trying to figure out the best way to build it. I want to stay flush with the floor and and am close - maybe 2" above. However, I can go flush for about 1 foot both sides but not the front. A sheet of Micore 160 would do it - but can only find Micore 300 locally. So, I keep playing with the materials to see what I can come up with. And perhaps 2" is no big deal.

 

[Gooserider]

My hearth area is 3x6 and I'm also trying to figure out the best way to build it. I want to stay flush with the floor and and am close - maybe 2" above. However, I can go flush for about 1 foot both sides but not the front. A sheet of Micore 160 would do it - but can only find Micore 300 locally. So, I keep playing with the materials to see what I can come up with. And perhaps 2" is no big deal.

What kind of r-value are you after?

Have you considered removing the subfloor under the hearth area?

What kind of thickness do you have to play with if you take out the subfloor under the hearth, and try to stay flush with the rest of the floor?

I know that in our house the living room floor consists of a layer of boards, then a layer of particle board and a wall to wall carpet w/ pad. I figure 3/4" each for the particle board and floor boards, and about 1/2" for the carpet and pad... Gives me 2" to work with.

Acording to Chimney Sweep Online's R-value handout table I can do 2 layers of 1/2" Micore @1.1 each, and a layer of 1/2" Durock @ 0.2, and a layer of 1/4" ceramic tile to get a 2.4+ r value total, with a quarter inch to spare... If I substitute plaster board for the Durock (not sure if that is structually OK or not) then the total goes to 2.65+ I thought 2.2 was about as high as it got for r-value requirements, so that was mostly what I had in mind to do when / if we ever go to replace our 1st floor smoke dragon.

If I needed still more, I'd consider adding a 3rd layer of Micore and going to a thinner Durock, and maybe even replacing the carpet with a thicker one, or otherwise increasing the thickness of the rest of the floor.

Gooserider

 

[bcnu]

I need an r of 2.5 for a Hearthstone Homestead. Subfloor already removed and with the new wood floor I have a little over 1 1/4 " below grade to work with. I have a 1/2" sheet of Micore and Durock laid down already and the tile would get me right where I want to be - but not enough "r" (thought we were going with the Heritage when I first started the hearth and it only needs r 1.5) So I keep playing with the materials list.

I posted another thread about r values as I've found three different ones for Micore 300. This website is the highest and lists 1" at 2.33 whereas Chimneysweep and the Mfg(USG) are right around 2.10 . I had asked if it was feasible to take the highest values - in which case an inch of Micore and 1/4 inch of Durock and 1/4 inch of tile get me over the 2.5. However, at the lower r values I would only get about 2.4. I could also solve the r value problem by building a 7" pedestal for the stove but my wife has an old wooden mantle and surround - and we need to stay as low as possible or the mantle gets too high. And we are also using a metal surround to reduce top clearance by as much as possible.

And - it won't help to suggest another stove - the Homestead is sitting on a dolly in front of the fireplace waiting to be temporarily hooked up when the new liner goes in the chimney this week

 

[Gooserider]

I'm amazed that your floor is as thin as you say it is, but it looks like you don't have much of a choice other than to go over the thickness. I don't know if Micore is available in 1/4", as that would presumably be enough to get you over, but certainly a 3rd layer of 1/2" Micore would work. This would put you about 1/2" above grade, and I would then make a wide angled "threshold" style molding to bridge the transition - at least a couple inches wide, I'd probably go for about 6" in a color that contrasted with the flooring and / or the tile on the new hearth.

Gooserider

 

[bcnu]

Goose - I should clarify that we removed one sheet of the subfloor leaving another below it. I remember reading something, I think from Elk, about compromising the structural integrity of the floor if you were to remove subfloor to the joists. Maybe I misread or don't understand that part of it. However, if I were to remove the other piece of subfloor I would have plenty of room to put down 2" of Micore and some Durock. Also, there is a full basement under the main floor with access to the floor from a suspended ceiling (just in case that might be of help). I can only get 1/2 inch Micore 300 here - and I've looked at all the distributors to see if I had a friend in an area that could buy and ship me some Micore 160 - but to no avail.

 

[Gooserider]

Hmmm.... I hadn't seen anything from Elk about a problem with removing the all the subfloor down to the joists and building back up with non-combustibles. I know he has issues with people cutting ventilation holes and compromising the fire barrier, but that is a different issue. I thought it was OK if you kept the floor as a solid peice, just changed what it was made from.

If there is an issue, I wonder if there is a way to compensate for it and retain the structural integrity without having to leave the subfloor layers - perhaps put in some added cross members between the joists, or fasten subfloor planking on the underside of the joists?

I hope he is reading this thread as it's an issue for me on almost any stove I would want to put in. The smoke dragon is a side load only stove, sitting on a raised hearth (one brick high, so ~4.5") that only has about 10" clearance in front. New stoves in the size range I'd want are almost all deeper front-back and narrower side-side, and also almost all have a front door, even the ones with side or top load doors as well. This means that just about every stove I'd consider will require a hearth extension in front of the existing hearth, probably 16-24" The living room is small enough that I would want to keep the extension flush with the floor in order not to have to loose the extension real estate when not burning.

Gooserider

 

[bcnu]

Goose, this is the info I read from Elk. I think I should have used the quote function to highlight it in gray?. This thread wasa also about installing a Homestead and getting the hearth flush with the floor. I'll put the reply in quotes:

"I read your manual concerning floor protection. It confirms the R-2.5 with a stove having 6” legs and bottom heat shield. The stove with 4” leg options and no heat shield is R6.6

Couple of point about some of your purposed installations
Do not remove the main sub floor to the joist.. That plywood is sized to carry the floor load and weight. Cement board 1/4 or 1/2”
is not rated in the mid spands 16” on centering of joist, to carry and properly distribute the weight. The orriginal sub floor decking has to stay. The rug and pad should be removed and if there is a layer above the main sub flooring, that too can be removed.
The instruction manual has done a very good job of explaining the required process of custom built pad ,including listing the r value properties of common materials,, for its construction. I would not use 1/4” cement board on the top layer it is not ridgid enough to be shifting the placement of a 400 lb stove, You run the risk of cracking it or breaking it even with it tiled. The .2R value of cement board is for 1/2” thickness. As for trying to make it flush with the rug, probably not going to happen. unless your rug has 2” pile.

Even with a bottom layer cement board two layers of micore and top layer cement board total R-2.6, tile in top, the finish product will be 2.25” thick from your sub floor. IF being flush is you biggest concern, You have one other option. Return the stove and buy another model or another manufacturer’s stove,that has the listed requirements for floor protection that will work.

Another note, floor protection is a tested process,, proven and becomes part of the stove installation and listing. This is the minium exceptable r-value. There is no penalty of exceeding the minium R-value.

Signature
Better Safe than Sorry "

 

[Gooserider]

Goose, this is the info I read from Elk. I think I should have used the quote function to highlight it in gray?. This thread wasa also about installing a Homestead and getting the hearth flush with the floor. I'll put the reply in quotes:

"I read your manual concerning floor protection. It confirms the R-2.5 with a stove having 6” legs and bottom heat shield. The stove with 4” leg options and no heat shield is R6.6

Couple of point about some of your purposed installations
Do not remove the main sub floor to the joist.. That plywood is sized to carry the floor load and weight. Cement board 1/4 or 1/2”
is not rated in the mid spands 16” on centering of joist, to carry and properly distribute the weight. The orriginal sub floor decking has to stay. The rug and pad should be removed and if there is a layer above the main sub flooring, that too can be removed.
The instruction manual has done a very good job of explaining the required process of custom built pad ,including listing the r value properties of common materials,, for its construction. I would not use 1/4” cement board on the top layer it is not ridgid enough to be shifting the placement of a 400 lb stove, You run the risk of cracking it or breaking it even with it tiled. The .2R value of cement board is for 1/2” thickness. As for trying to make it flush with the rug, probably not going to happen. unless your rug has 2” pile.

Even with a bottom layer cement board two layers of micore and top layer cement board total R-2.6, tile in top, the finish product will be 2.25” thick from your sub floor. IF being flush is you biggest concern, You have one other option. Return the stove and buy another model or another manufacturer’s stove,that has the listed requirements for floor protection that will work.

Another note, floor protection is a tested process,, proven and becomes part of the stove installation and listing. This is the minium exceptable r-value. There is no penalty of exceeding the minium R-value.

Signature
Better Safe than Sorry "

Well I added an extra set of quotes to make it a little clearer, but it does sound pretty explicit and difficult. I wonder what the answer would be to replacing the probably pretty thick (3/4"?) decking with something thinner but presumably as strong, like a layer of 1/8" aluminum or steel plate? It works in industrial applications, which take heavy loads, and would get you back at least some of the thickness you need for non-combustibles, as well as meeting the suggested idea of including a layer of metal in the pad "sandwich"...

Paging ELK, Paging ELK, please report to the help desk......

Gooserider

 

[begreen]

FWIW, I would prefer to have a substantial hearth, or be completely flush. It seems easier to trip over something that is just a little above floor height than something that is say 6" or more. The other benefit is less distance to stoop down when feeding the fire.

 

[bcnu]

What my wife really wants is to use an old wooden mantle and surround we have. It's been a challenge to try and keep the hearth low so the mantle isn't too high. We looked at the metal surround for the Hearthstone and even adding a metal deflector that would attach to the lintel. In the end we may chuck the wooden surround as we just cant get it low enough to look right. If that happens then I either stay low ( I'm at 1" above the floor with the lowest option) or I could build a pedestal, 7 inches high(r 6.6) that the stove would sit on - and that would give me about 18" in front and 12" on each side that would only need floor protection - flush with the wooden floor. The fireplace opening is 36" so perhaps I could build the pedestal that wide and come out 18" to make it look more balanced . I took off a 12 in. high hearth that spanned the entire 72" in front of the fireplace. Never dreamed it would take this much effort :bug: Thanks for all the info - I have probably stolen EatenbyLimestones original thread. Hope EBL has gotten as much out of it as I have.

 

[Gooserider]

What my wife really wants is to use an old wooden mantle and surround we have. It's been a challenge to try and keep the hearth low so the mantle isn't too high. We looked at the metal surround for the Hearthstone and even adding a metal deflector that would attach to the lintel. In the end we may chuck the wooden surround as we just cant get it low enough to look right. If that happens then I either stay low ( I'm at 1" above the floor with the lowest option) or I could build a pedestal, 7 inches high(r 6.6) that the stove would sit on - and that would give me about 18" in front and 12" on each side that would only need floor protection - flush with the wooden floor. The fireplace opening is 36" so perhaps I could build the pedestal that wide and come out 18" to make it look more balanced . I took off a 12 in. high hearth that spanned the entire 72" in front of the fireplace. Never dreamed it would take this much effort :bug: Thanks for all the info - I have probably stolen EatenbyLimestones original thread. Hope EBL has gotten as much out of it as I have.

I don't know what to say about the mantel issue, but the comment about building a pedastal does raise an interesting point - What impact does having a "split level" hearth have on the R-value requirements? The manuals all seem to have the assumption that the hearth is the same height for the entire dimension, and has to have the same r-value. Plainly it is possible to build a "split level" hearth, where the stove is at one height, and the rest of the hearth is at a different, lower level. (It might be possible to build a "step down" design, but that would be a completely different set of issues)

However we can see from your earlier quote that there is a BIG difference in the required R-values for long and short legs on the same stove. Presumably if one had "extra tall legs" there would have been a lower number due to the increased clearance between the stove and the hearth. If one built a split level hearth where the part the stove sat on was (for discussion sake) 6" above the rest of the hearth, it would be just like the stove had 6" taller legs - I would expect that to lower the required R-value for the remaining area simply by the virtue of the increased distance to the stove, just like increasing the CTC number on a wall decreases the need for shielding.

I guess the easiest way to put it would be to ask "What is the "R-value" for an inch of empty space?"

This wouldn't help with the mantle problem since you need to lower the stove to work on that, but it might make a big difference for a setup like mine, or anyone else that had a similar issue of needing to extend an existing raised hearth, but wanting to keep the extension at floor level.

Gooserider

 

[elkimmeg]

I think I have a solution the original sub flooring can be removed from joist centers . This is a support issue. A lot of weight above. Since it can be gotten to underneath,
What I suggest tis to remove the first sub flooring. to the floor joist ,then solid block with 2/8 2/10 or any combination flush to the top of the floor joist between the joist.
The nailing or support is the tricky issue of the blocking. But toe nail them and side through the joist. as best you can. Keep the flush to the top of the joist then using 2/4 sister the 2/4 to the original floor joist to add support of the block Nail the 2/4 supportst 16 common nail every 8" or less . You then can nail down the blocks from the top to the 2/4.

You now have added the support the plywood sub flooring did. You can install cement board or Hardi backer board to your desired height. Personally working with both products, I prefere working with hardibacker board ,it cuts easier. This will gain you 3/4" more inches and you can build up what you need. The support issue has been taken care of. In fact much stronger than original plywood. Naturally more work, but doable, a solution you were looking for.

When I made my first suggestion of not removing the plywood sub floor I was not thinking along these terms. It took reading this post, to realise there was another possibility.
When reading that there was access from below, It all fell into place and made sense.

 

[begreen]

I guess the easiest way to put it would be to ask "What is the "R-value" for an inch of empty space?"

It depends on whether or not the air space is ventilated. This hearth article lists 1.47/in. if the space is ventilated.

We've seen some very nice elevated hearths posted here that raise the stove up 12-18". If made correctly, they provide a nice non-combustible hearth, raise the stove to an easy to use height, and eliminate worries about tripping, R values, etc. With some planning, a nice niche for wood and kindling storage can be built in too.

https://www.hearth.com/articles/64_0_1_0_M1.html

Here is a nice article from the ceramic tile institute that gets into the code, insulation values and options for building a tile hearth.

http://www.ctioa.org/reports/fr77.html

 

[Gooserider]

I guess the easiest way to put it would be to ask "What is the "R-value" for an inch of empty space?"

It depends on whether or not the air space is ventilated. This hearth article lists 1.47/in. if the space is ventilated.

We've seen some very nice elevated hearths posted here that raise the stove up 12-18". If made correctly, they provide a nice non-combustible hearth, raise the stove to an easy to use height, and eliminate worries about tripping, R values, etc. With some planning, a nice niche for wood and kindling storage can be built in too.

https://www.hearth.com/articles/64_0_1_0_M1.html

Here is a nice article from the ceramic tile institute that gets into the code, insulation values and options for building a tile hearth.

http://www.ctioa.org/reports/fr77.html

Well the space certainly would be ventilated in the scenario I'm describing, but I'm not sure we are talking about the same thing... If we are, then all is pretty good.

I'm attaching a drawing that I hope will give a better description of my scenario. I have a stove of unknown origin that has a manual specified R-2.0 hearth requirement, when using its supplied 6" legs. I want to keep the hearth thickness even with the floor for most of the hearth area, but don't mind having the stove itself on a pedastal made from bricks on edge.

So I put down 1/2" of Micore, R=1.1, and 1/2" of Durorock R=0.2, for a total of 1.3. Under the stove itself, I build a pedastal of bricks on edge, 4.5" high, R=0.8 for a total R-value of 2.1, which is fine. But what about the tiled area? Does the 4 1/4" of air space that the bricks put on top of the tile count towards the effective "R-Value" This is the green area on the sketch, it certainly is "ventilated" but does it count, if so, for how much? If we use that 1.47 / inch number you mentioned above, then the value of the tiled area would be about 7.5, or more than three times the area under the stove!

Is this correct? If so, it would make replacing the smoke dragon a heck of a lot easier for me, because it would mean that all I would really need is to rip up the carpet in front of my existing raised brick hearth and put a layer of ceramic tiles down on top of the subfloor!

Gooserider

 

[bcnu]

Thanks for all the info guys. After all was said and done I went back to the (almost) original plan and the hearth and extension sits about 2" above the floor. I used 1" of Micore, 1" of Durock and 1/4" tile to get the the needed r 2.5. I would have looked into removing more of the subfloor and bracing the joists but the pocketbook needs a rest. We are going to use the wooden mantle and surround - attach it per code and enjoy. I'll take some pictures and figure out how to attach them.

Goose - nice job on the hearth drawing. A picture really is worth lots of words. You could read the Hearthstone Homestead manual on line to see if it hepls with your questions. I could have built a 7"or higher pedestal with r 6.6 and the floor protection only needed to be non combustible. The hearth would have had to extend 16" infront of the door, so it wouldn't look quite like your drawing.

The stove will be installed with the chimney liner this Friday. I think I'll even be able to get the break in fires out of the way this spring. Woo-hoo! Almost can't wait until Winter :lol:

I'm just getting started bucking up a couple of the trees that came down in the storms last winter. Nothing too big - but it's about time to begin posting my cutting questions on the other forum.

 

[Gooserider]

Well my question is a mix of "theoretical" in terms of what the options are for general hearth design and practical in terms of what I will need to do when / if we replace the existing smoke dragon. At this point we can't afford it, but hopefully it will be possible at some time in the not to distant future.

The GF and I don't really know what we will pick for a stove, however the design of our hearth and chimney put us under some really serious constraints. The Hearthstone and Heritage stoves are on the "short list" of stoves we could consider (I think) since they can be setup with rear exits.

Our hearth setup is such that we would end up with something looking sort of like my picture, so I do worry about what kind of R-value I would end up needing on the lower section.

One of the big question marks is just what is under the existing brick section - I know I get 0.8 from the bricks, but what is under them to give me a total for the hearth? Given the ~25-30 year old stove, I'm guessing a layer or two of cement board or durock as I don't think they had Micore in those days... Presumably I will have to do some 'surgical exploration' to find out for sure - even then, how do you tell? If it's not that high, I might have to either choose a lower R-value stove, or tear up the brick hearth and rebuild under it, which would really be tricky, though a chance to learn some masonry...

Gooserider