Am I building my hearth correctly

[Brian C]

So I bought a house last year that had a Century FW240007 wood stove in it with the ugliest looking hearth pad and wall protectors. I then remodeled my house during the winter, so I took out the stove and put it in my completely packed shed until I decided if I wanted to put it back in. I did some research along with going to a place that sells wood stoves and the salesman there seemed like he knew what he was talking about. I asked him what clearances do I need for my stove and if I definitely needed to put a wall protector. He said that on the back of the stove should be diagrams of the clearances. He also said that as long as I go off of the diagram I should be fine for the wall. The diagram on the back says if you are putting your stove on a diagonal into a corner then you need 7" on the sides, and 15" to centerline of pipe to wall and for floor you need 8" on sides and 16" in front.

So maybe, maybe not I jumped the gun and built my ceramic tiled hearth on top of my vinyl flooring that's on concrete slab according to those dimensions(picture File too large to upload). I have approx. 48 x 48 2x4 platform (3 1/2" high) then put 1/2" plywood on that, then 3/8" or 1/2" durock, then ceramic tile. Question 1: Does that seem like it is correct/safe?


Seeing I like to jump the gun, I lit a small fire as soon as I got it in and everything seemed good except for pipes were crimped and placed in wrong direction because of previous house owner. Next night I got fire barrier caulking and applied it around the pipes and wouldn't you know it I lit a little bit bigger fire before the caulk cured and house started to smoke up. Luckily it did because my fire alarm went off and I went to check the pipes and I felt the wall next to it and it was hot as can be. So I think I am going to make a ceramic tiled wall protector over durock. And that is why I am here posting this long ass thread....I like to tell stories I guess...so my next questions.............


1. Do I need a 1" spacer off wall or can I put durock over sheetrock then tile over durock?

2. If I need spacer do I need full openings on sides, top and bottom and how much off bottom?

3. If I need openings can they be incremental openings for aesthetic purposes or whole thing?

4. Any clearances for electrical?

If you are still reading I am impressed...and if you respond with some knowledge I would be most grateful...


Thanks!

 

[BrotherBart]

I ain't the guy to go to for clearances but a couple should be along soon. Welcome and you came to the right place for info to make that installation safe.

 

[MnDave]

You need to use double wall stovepipe if you want to use the 15" centerline to combustible dimension on your stove. That requirement is for stove alone. The singlewall stovepipe needs 18" from combustables. It is a gotcha that all installation manuals should spell out.

Electrical is considered combustable but I imagine that you have that behind the sheet rock (combustable).

There are formulas for reduced clearances but they are tedious as far as I am concerned.

MnDave

 

[MnDave]

Keep in mind that if your stovepipe has an elbow(s) and connects at the wall, the horizontal section needs the same clearance from the ceiling as the vertical section to the wall.

It sounds like a cheap solution will be doublewall stovepipe. To bad you just reversed the fittings.

MnDave

 

[fossil]

Brian, what you really really need to do is NOT burn in that stove again until you've given us all a chance to straighten this whole installation out with you. Your beautiful family in your avatar is the only reason you need to proceed with extreme caution here. I have this same stove in my workshop. I have all the original Manufacturer's documentation, such as it is. Wall protectors may or may not be appropriate/allowed. The manufacturer doesn't mention them, which may well preclude the use of wall protection to reduce minimum required clearances to combustibles as shown in the installation documentation.

But what really concerns me is the smoke in the house. A properly installed/operated solid fuel-burning appliance will almost never put smoke into the living space...the draft through the properly designed/installed system will draw air into the flue from the living space through any small openings that may exist.

So far, no...it does not sound like it's correct and safe (with the limited info provided). A whole bunch of pictures, inside and out , would certainly help. Just hold off on the fires in that thing for now, buddy. Rick

 

[begreen]

The hearth appears to be shy on insulation requirements. Did you use Durock Next Gen brand cement board? If this is Hardibacker or if that was 3/8" Durock or 1/2" original Durock it is under the requirement it is not up to requirement. If you used 1/2" NextGen Durock then you are close enough that I wouldn't lose sleep about it. But if not, you may want to fix this. Also note that the diagram says 18" in front.

I agree with fossil about the clearance reduction. The manual is minimal and does not list the option of clearance reduction per NFPA wall shielding. Go with double-wall pipe here and sleep better at night.

Post some pictures inside and out of the current installation. This is not a place for cutting corners, especially with a beautiful young family. It's pretty easy to reduce the image size. Here are some guidelines about posting pictures on the forum: https://www.hearth.com/talk/threads/putting-images-into-your-forums-posts.87212/

 

[MnDave]

15" to centerline of pipe to wall

Incorrect based on begreens diagram of your stove. 15" to edge of stove outlet. Delta 3 inches.

And again, that is stove to wall, not stovepipe to wall as I described above.

Keep in mind that insurance companies will not cover a loss due to a faulty installation.

MnDave

 

[MnDave]

I think you are ok on the materials and thickness of your hearth but I am not sure on the side and front dimensions of your hearth because I do not know the dimensions of your stove.

I bought a home with a stove that was installed by professionals. The hearth was 2x4 with 1/2 plywood, metal lath with thinset bond to 1/4 inch thick marble. You have that and more. begreens diagram states floor protector equavalent to 3/8 inch millboard. Not sure what millboard is but I would think that tile on durock is at least as good. How thick of tile?

Here is a link that sheds some light on that "millboard" specification. Yuk!

https://www.hearth.com/talk/threads/what-is-mill-board-local-lumberyard-never-heard-of-it.18129/

I think that the floor protector specs are very conservative. I am guessing that they are designed to prevent a fire originating from a floor in the event a flaming log that has rolled out of the stove after a door/glass breach and is undetected ie. assumes that no one is home to answer the screaming smoke detectors or the occupants are deep sleepers or have dead batteries in there smoke detectors.

The idea that the log would only roll 18" from the front of the stove (before it drops onto say carpeting) shows you how contrived these specs are. This is the politics of government agencies which are heavily influenced by insurance companies. In other words... it is a game of minimums. Think reasonable maximums and you will be building in a "real" margin of safety.

MnDave

 

[begreen]

Nonsense. There's a difference between seat of the pants, feels good enough guesswork and measured material insulation. Equating one stove's requirements to another is irrelevant. Follow the tested requirements provided by the manufacturer and not what was installed for another completely different stove.

 

[Brian C]

Thank you everyone for all your responses..I'm at work so when i get home i can try to get pictures as well as more dimensions. I actually measured the centerline of pipe and luckily it is 18" not 15".

 

[DAKSY]

Thank you everyone for all your responses..I'm at work so when i get home i can try to get pictures as well as more dimensions. I actually measured the centerline of pipe and luckily it is 18" not 15".

If you've got single-wall connector pipe, 18" centerline is NOT to code. The 18" is from the EDGE of the pipe.

 

[jeff_t]

I would highly recommend flue and stove top thermometers for safe and efficient operation. The wall shouldn't get THAT hot under normal operation, even if it is a little close.

Crimped end goes down, by the way. Any smoke in the house is likely a draft issue, though sealing the connections isn't a bad idea.

 

[MnDave]

Nonsense. There's a difference between seat of the pants, feels good enough guesswork and measured material insulation. Equating one stove's requirements to another is irrelevant. Follow the tested requirements provided by the manufacturer and not what was installed for another completely different stove.

Agreed, and that entered my mind while lying in bed this morning. So I went to my new stoves' installation manual and based on what I read, my old hearth, which was built in 1998 which I have since removed, was inadequate by todays standards which I believe are dictated by NFPA (National Fire Protection Association).

So disregard my comment about my marble hearth that was installed by professionals. It seems that there is a moving target when it comes to installation requirements.

If you have an old stove you might want to consider that the installation manual could be out of date in the area of floor protection.

I went to the manual for my old stove. It reads:
The stove must be installed with a floor protected by a UL Listed Floor Protector of 3/8" Asbestos Mill Board or 2 1/4" Masonry Brick. The floor protector must extend at least 16" in front of, and at least 8 " to either side of the appliance.

My new stove has entirely different wording:
US Installations, It is neccessary to install a floor protector of a minimum of 1" (k value = 0.49, R value = 0.59) of non-combustable material a minimum of 16" in front of the glass and 8" to both sides of the fuel door.

They do have a section called "Calculating Alternate Floor Protection Material" which gets into k value but it is to detailed to reference here.

Brian I think you need to start from scratch.

MnDave

 

[Brian C]

So i got a couple specs at lunch...I used 1/2" pine plywood and 1/4" wonderboard and 1/4" ceramic tile. I'll get more dimensions in a few hours.

 

[MnDave]

Here is an excellent article about hearth material.

https://www.hearth.com/econtent/index.php/articles/k_values_what_does_it_all_mean

I did not read it in detail yet.

They list wonderboard and tile. I thick your shy of the overall 0.49 but I would need to really sit with this to be sure.

I have to run.

MnDave

 

[begreen]

That is way under specification. You will need to redo the top of the hearth. Use a double layer of 1/2" Wonderboard or a single layer of 1/2" Durock Next Gen for underlayment.

 

[Brian C]

yea I had a feeling I had to redo it...sucks lot of hard work and it looked good for my second time tiling..whats even worse is I gotta figure out how to take it out cuz I ramset it into place

 

[begreen]

Sorry Brian. You did a really nice job too. It's quite professional looking for a first try. I'd be tempted to upgrade the stove to one that only needs a non-combustible hearth.

 

[Brian C]

Thanks begreen...do u think it would be worth it? I don't know how sufficient/insufficient my stove is and if getting a new one would be that much better...I think my stove is 2007..if so any suggestions on a medium quality/medium price one and possible cost?

 

[Brian C]

Though I feel like all I do is work on my house since I bought it a year ago, I have to make sure my family is safe so if it makes more sense to rebuild hearth than buying new stove then no question I'd do that. Also random question but has to do with heating...Anyone know good place to sell oil burner besides craig list?

 

[begreen]

I am almost 20 yrs later since moving in and still regularly doing work on the house and property. Together with wood splitting/stacking and lots of gardening it's my exercise program.

Your stove is a decent basic stove and your installation is good enough that you are not going to burn up the hearth in a season of burning. We're sticklers for safely because we also hear the dark side of unsafe installations here. With a little one in the house it makes it even more important.

Hang around here, ask lots of questions and separate opinions from facts. There are stoves that we can recommend, but what you have will get you through this winter if money is tight.

 

[raybonz]

So i got a couple specs at lunch...I used 1/2" pine plywood and 1/4" wonderboard and 1/4" ceramic tile. I'll get more dimensions in a few hours.

Hmm personally I would use 2 layers of 1/2" Durock Nexgen with all layers thinset to each othe and each layer seperately screwed every 3" to the subfloor followed by tile etc.. Durock Nexgen is rated 0.39 R-value per 1/2" so this equal 0,78 R-value (with 2 layers of Durock) and exceed the manufacturer's minimum requirement. I am not discounting other people's advice but BeGreen guided me when I built my hearth and a few others and they did not steer me wrong. Fossil and BG know their stuff!

Ray