Rebuilding a flush hearth

[tickbitty]

I would like some advice on building a hearth that's flush with the floor (or close to it.)

My hearth is flush, or nearly so. It's ceramic tile and measures 18" deep by 64" wide. Presumably this tile is on top of wood and since the house was built in 1953 I doubt there's any fancy stuff in between. It's probably about half an inch tall and has wood strips around the edges.

I had thought that I could just use stove board on top of it and in front of it to meet any codes on inserts or even maybe a freestanding. But because of the 64" depth and etc, it seems like it would end up looking pretty weird, with old hearth sticking out the edges, and it would be a bit uneven too since it would be a little higher where the hearth is. If I got a pre-made hearth I imagine I would have the same problems with unevenness and dealing with the old stuff underneath, plus I would have clearance issues if I go up.

I don't think I could do this myself but I have a handyman friend who could if I tell him what exactly I want done. Would it be necessary to cut out the floor or could all the necessary protection be done over it without raising more than an inch or so? I was just thinking of trying to do something that looks about like it looks now, with the 6" terra cotta tiles, but is twice as wide at 36" or maybe even around in sort of a half circle from the shape it is right now.

There's a crawl space underneath the house so some kind of support underneath might be possible, but I really don't want to cut out any support beams or anything. Would prefer to leave the wood floor underneath what I do but it's not really necessary.

I know this has been posted about before so if anyone can pass along links with specifics or pictures I would really appreciate it! Thank you.

 

[tickbitty]

Also, should whatever is built just go up to the inside bottom of the masonry fireplace, or extend in slightly, or more?

 

[Green Energy]

To be safe, code compliant, and not violating your insurance, you need to provide meet the non-combustion clearances for your stove and as required by your locality. This means that not only is the surface is non-combustible, but that there is adequate R-value beneath the surface, i.e., beneath the ceramic tile.

This may mean installing a layer of the proper substrate beneath the ceramic tile with the proper thickness. Some installations allow for heat shields for alternative clearances.

 

[tickbitty]

Right, that is what I intend to do, and that is why I am seeking information here.
Right now I am not looking for info for a *particular* stove (although the insert I am currently favoring does not seem to require anything but the hearth to be "non combustible") though, just trying to figure out what I would have to do to make this hearth right and pretty much good to go for most stove/inserts that I would choose. I learned the hard way to look at this carefully as the last insert I bought actually required a raised hearth (not just R value of a certain amount) and my flush hearth could not be made to work for that stove.

I don't know a lot about Micore/hardibacker/durarock or whatever sandwich is typically used, and I was hoping someone here could help fill me in on whether some combination of these would have to be layered on TOP of the wood floor currently under my hearth, or whether the wood should be cut out and replaced by one of these other subfloors, or what. I intend to double the depth of the hearth as well, from 18" deep to about 36" by 64" wide with the corners at angles.

I know someone with the tools and ability to do this, but he would not have the knowhow to understand the specificities of these materials so I would have to give him those specifics on what to do so he could do it.

 

[nelraq]

I would suggest that you decide which heating unit you are going to buy before you start renovating your hearth. Some units definitely require hearth pads which are built with a specific R value.
Others, like you said in your last post, only require that the hearth be made of a non-combustible, ember proof material such as slate, tile brick, etc.

I recently put in a new wood stove. My hearth pad is made of 2 - 5/8" pieces of plywod screwed together - and covered with slate - with grouted joints. The pad is directly over a wood floor.

It was inspected the other day and passed with flying colours. The inspector did ask to see the manual, so that he could check the floor requirements.

 

[Overkill]

A friend of mine is going through the same delema as you with his quadrafire 7100. I know when I built my hearth pad it required a listed r-value. The top layer has to be none combustible. I used micore, hardie backer and granite on top. Well anyway we found a product strait out of NASA that gives you a 20 r-value at 30mils thick. Thats .003 of an inch! Cascade TG-1(1G) Thermaguard Heat Shield look it up had a coworker use it on the underside of his alcove installation he told me the top space above the alcove does not even register heat. Only problem its 100 bucks a gallon.

 

[tickbitty]

Wow, so where could I get like a pint of that NASA stuff then?! Actually, don't even know where to get Micore.

So Micore goes on top of the floor, or subfloor, with Hardie backer (or cement board, or Durock?) on top of that, and thinset and tile on top of that? And heat resistant grout? Or is some other sandwich or order recommended?

I would like to maximize the R value despite that I think I will be going with a stove that simply requires "non combustible" just because I only intend to do this once and don't want to short change it if it's only the difference of a few bucks or whatever.

 

[Overkill]

For Micore and such you can locate that product in a local drywall supply house that carrys USG products. In your area try Building specialties. For the thermagaurd try www.parts-express.com. Well after serching myself I found the maufactorer Cascade Audio Engineering. The manufactorer claim 30mil equal 1/8th inches and only
R-12. I would trust the manufactorer before the resaler. Like I said my Co-worker said it is the cats meow. ;-P

 

[tickbitty]

Hmmm. Interesting. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-232
Don't think I will probably end up being the first to try it though - says it applies with a spray gun etc? Wish we could get a smaller amount than a gallon it would certainly be worth a try!