hearth required after gas log conversion?

[jonnies]

I installed a vented gas log set in an otherwise conventional masonry wood-burning fireplace. It works great.
I'm now in the process of doing some room renovations, including tiling over the brick fireplace walls and refinishing the hardwood floors. In the process, I removed the raised brick hearth in front of fireplace, down to the underlying concrete slab. Consequently, the bottom of the fireplace opening is about 10 inches above floor level.

Both a floor refinisher and a masonry contractor said that since the fireplace was now gas, there was no requirement for a hearth, and hardwood flooring could be laid over the concrete slab, right up to the fireplace wall. This will make the room look larger, and give the fireplace a very contemporary look (with the right doors).

I contacted the local building inspector (I'm in New Jersey), and was told that because the fireplace was built for wood burning, that it must remain to Code for a masonry fireplace, even if converted to gas logs, and therefore a hearth made of noncombustible material must be present (it can be at floor level). The only exception is if the gas log manufacturer can provide data and proof that a hearth is not required.

I contacted the manufacturer, and was told they do not provide any specifications regarding a hearth due to the wide range of variations in the fireplaces into which their log sets are installed. Their recommendation was that since the fireplace COULD be used to burn wood, then a hearth is required by code. But technically, since the gas logs do not emit sparks or embers, and they are raised well above floor level, a hearth serves no purpose.

I would prefer the look of a uniform hardwood floor without a hearth area in front of fireplace. Does anyone have any experience with whether the building codes for a masonry wood fireplace still apply if its converted to vented gas logs? Has anyone completely eliminated their hearth after converting to gas?

 

[jtp10181]

Gas Logs are tested to be installed into a fully functioning and legal wood fireplace, hearth included. Even with a gas log installed, its still a wood fireplace, the gas logs are easily removed.

Even if you read the fine print on gas inserts you should have a hearth in front, but I don't think anyone really worries about it.

 

[DAKSY]

Go here:

http://www.hyccompany.com/StoveBoards.html

Find a local hearth shop that sells them. ($80 +/-)
Buy one, take it home & set it in front of your fire place.
Save the box it came in.
It is listed, so it'll pass inspection.
After the inspection, put it back in the box & take it back to the hearth shop.

 

[jonnies]

Actually, I'd pass inspection the way it is now, because the roughly 2x6 foot concrete slab extension qualifies as a hearth. Not pretty, but it meets the Code.
I want a completely flat floor, so my plan was to grind the slightly uneven concrete down to accommodate either the thickness of hardwood slats or ceramic tile, the preference being hardwood.
But you raise a good point. Since my firebox is raised higher than 8" off the floor, according to the Code, I only need a thin noncombustible layer on the floor (I think its 3/8" min. if I remember correctly). A hearth blanket like you referenced, or even a panel of tile on a backer board, would serve that purpose _IF_ the code allows it to be non-permanently attached. I'll have to check into that.

Thx.

 

[ruth140]

i agree with bob...but save the stove(hearth) board so when you go to sell the house you can put in back on the floor and pass the C.O. for selling the property.

 

[jonnies]

My town uses the International Residential Code for Fireplaces, that says:

When the bottom of the firebox opening is raised at least 8 inches 203 mm above the top
of the hearth extension, a hearth extension of not less than3/8 inch thick (10 mm) brick,
concrete, stone, tile or other approved noncombustible material is permitted.

It does not specifically say that this material has to be permanently fastened, but neither does it
say that it could be a separate (and removable) piece. I would be very surprised if was permitted
to be unfastened. Do you know for sure?

 

[ruth140]

it is permitted, you can also use a piece of "wonderboard" the concrete board they use in shower walls. it is not attractive, but it in noncombustible and you can also pick it up after your inspection and put in away.

 

[jonnies]

Interesting! Thanks Ruth and Bob.
Jon.

 

[ruth140]

i have seen some inspectors pass a fireplace if you put a hearth rug on the floor in front!
for example if the fireplace( wood burning) required an 18" hearth and the customer had a 16" they let them put a hearth rug down.
not sure that will work for inspector, but it shows it doesnt need to be fastened to the floor.

 

[jonnies]

I checked with our town's building inspector. Definitely NOT acceptable to have a removable hearth material.
The hearth and extension MUST be permanently fixed to the structure.
Hearth blankets, stove boards, cement board, tile panels, etc can not take the place of a proper hearth. They can be used to provide further protection around the hearth, but never in place of it.
Makes sense.

 

[ruth140]

each inspector has their own interpretation of the code.
a woodstove for example is placed on a "hearth pad".
it is a one piece pad...not attached to the floor.....yet it is code.

 

[jonnies]

I hate to beat this to death, but that analogy just isn't correct.

Its like removing the seat belts in your car, but telling the cop who pulled you over that its ok because you only drive slowly and you added extra bumpers, so you don't need them, but you'll re-install them when you sell it. If the law says a registered vehicle must have seat belts, then you have to have them, regardless of how you drive or how you may have modified your car.

The code I quoted is written for masonry fireplace construction, not for a self-contained wood-burning stove.
What you are describing is proper operation of a wood burning stove, i.e., its acceptable to place a hearth pad beneath it.
What I have is a functional, open, masonry wood-burning fireplace, which has specific construction standards, whether I build a fire in it or not.
From what I understand, the only way to circumvent the code is to permanently alter the fireplace to make it unfunctional (e.g. seal it up), or to put an (approved) insert in it, such that an open fire could not be made.

Jon.

 

[webbie]

I believe the original advice was the proper advice. It is a wood burning fireplace and the hearth should be up to code for that.
What an inspector will accept (wrongly) is not the proper bar to set.

The logs can be easily removed by the next person who owns the home - or by you - and the fireplace converted back to wood.

I don't think there is even a question here - a regular hearth is required....based on what the fireplace construction is now. I'd have to look further to see what the requirements for a raised fireplace are (they might differ, since heat is not transfered as much).

 

[jonnies]

Agreed, I'm convinced a hearth is required after reading the code myself and speaking with inspectors.

The hearth specs for a raised firebox are indeed different if the bottom of the opening is above the plane of the hearth. The Code I referred to requires min. 2" thick hearth extension if the firebox opening is lower than 8" above the hearth and mn. 3/8" if its more than 8" above it.

Thanks all. I'm going with tile flush to the floor.
Jon