Wooodstove too heavy for the floor? Am I being paranoid?

[sksmass]

This is a question about weight. I am thinking of installing a Hearthstone Equinox. One thing holding me back is concern about whether my floor can take it. I don’t want to cause structural damage, or worse yet, have the the stove end up in my basement!

The Equinox weighs in at 689lbs and would be on a hearthpad that would add another +350lbs. So we are talking about ~1050lbs of total new dead weight.

You can see in the diagram below that the stove will be going in front of an existing masonry chimney. Near the intersection of two 9x12 carrying beams (the hot pink lines). The 2”x10” floor joists are 16” on center and span about ~15’ across the living room. The joists rest on a foundation wall on the west end and one of the carrying beams on the east end. The Equinox itself has a footprint of ~6sf and would rest on a 4’x7’ (28sf) hearthpad. So the weight would be born primarily across 5 joists and the center of mass would be ~30” from the inside wall.

I ran this by an engineer friend and he said he would feel more comfortable with either 1) a lally column under the stove or 2) adding sisters to the five key joists. Both of those solutions are undesirable. There is a finished basement beneath the stove that I really do not want to cut into with columns and sistering the joists would require removing the dropped ceiling and relocating a bunch of wiring -- turning a merely large job into a huge job.

So, the question is,
1) Given the above information, would you have any second thoughts about doing the install?
2) Have any of you guys EVER seen a situation where installing a woodstove and hearthpad caused a structural issue due to the weight?

 

[Slow1]

I have seen this sort of question come up before. As I recall the answer is generally that unless you have an unusually weak floor you have nothing to worry about. Examples given include having a party with a bunch of people standing in the room - how much do they weigh (how many people can stand there and what would the weight add up to...) and would that concern you? What about a water bed - consider how much that weighs... how many lbs per sqft are we talking here - remember the pad will help spread it over the area so do that calculation too...

Anyway, it will be interesting to hear other responses.

Not to put down engineers (I happen to be one too) but when asked on these sorts of things adding more support etc will always make an engineer feel more comfortable. That really isn't the same thing as saying "it is necessary" to do so.

 

[FireWalker]

My Equinox has yet to fall through to the basement and my floor joists are on 24" centers.

Is the beam running up and down the page supported near it's center, or does it clear span? I'm guessing it gets picked up at the chimney. Also looks to me as though the masonry mass of your fireplace/hearth supports the joists coming across from the foundation wall. Plenty strong right there. Do you have 3/4" subfloor with 3/4" hardwood (2 layers of 3/4")?

As posted, look at it differently, would you break-up a couple of well rounded folks from hugging/dancing at that or any other location in your home for fear they may end up in the basement?

 

[sksmass]

Is the beam running up and down the page supported near it's center, or does it clear span? I'm guessing it gets picked up at the chimney. Also looks to me as though the masonry mass of your fireplace/hearth supports the joists coming across from the foundation wall. Plenty strong right there. Do you have 3/4" subfloor with 3/4" hardwood (2 layers of 3/4")?

The north-south beam is supported by two lally columns, one on either side of the chimney. I don't know the thickness of the subfloor. The house was built in 1940 so the subfloor is wood planking not plywood but I am unsure of the thickness.

 

[fossil]

Invite about 7 or 8 folks over, serve up a few drinks, have the people cluster within the proposed footprint of the hearthpad, put on some good dancing music, and sit back to see what happens. If none of them end up in the basement (which I predict will be the case) then I don't think there's a problem with the floor strength. 37 - 38 psf shouldn't be a problem. Rick

 

[begreen]

Good idea Rick! I was going to say 3 linebackers on a heavy couch would probably weigh more. The weight is distributed over many joists by the hearth pad, floor and sub-floor. I'd think it would be fine unless there are some serious construction flaws.

 

[weatherguy]

Dont we have this question every year and then someone chimes in with fat women jokes?

 

[Pagey]

Yes, but this thread has by far one of the best.diagrams.evar.

 

[fossil]

Yes, but this thread has by far one of the best.diagrams.evar.

It's a beauty. But I'd get that rug outta my office, and find out who those dudes are in the living room. :lol: Rick

 

[Bobbin]

So where are the fat lady jokes?

(that is an impressive diagram)

 

[sksmass]

...I'd get that rug outta my office, and find out who those dudes are in the living room. :lol: Rick

Ha! That's me staring lovingly at my new woodstove and my wife sitting there rolling her eyes.

So, I am getting the feeling that the floor is probably OK. I'm gonna go with that. I guess if I start to notice the floor sag AFTER I do the install I can always jack it up, straighten it out, and reinforce it after the fact. I suspect it will never be necessary.

Of course this means that I now won't be able to have BOTH a woodstove AND a party of dancing linebackers in my living room at the same time. I guess that's OK. If I had to pick one I guess I'd rather have just the woodstove.

 

[PapaDave]

I agree with Rick, but the rug in the Laundry/Mud room is very tasteful and should stay.
However, I'd like to know why the Dining room is so far from the kitchen?

 

[fossil]

...now won't be able to have BOTH a woodstove AND a party of dancing linebackers in my living room at the same time...

Of course you can. Once the woodstove's in place and burning, there's no danger that the linebackers will be dancing in the same spot as the stove. Trust me, we do this sort of thing all the time. %-P Rick

 

[Beetle-Kill]

Alright, cut to the chase- Here's what we all know you're after- www.californiapoles.com - Trust me, if I could I would. I only need the accesories, and I can't afford them. BTW, the floor joists will probably be sufficient, but if you notice floor sag (more noticable from the bottom than top), You could probably enlist your engineer to draw up a simple, cantilever steel support brace, that will help carry the load. The sides of the brace, when finished with drywall, can be used to hang pictures, bookshelves, or whatever you want to stick in those areas........But a straight-up, adjustsble column can be blocked out, and serve a variety of uses. Relieving your concerns about the floor giving-way not the least of them. You'll figure it out, good luck and keep us posted. JB

 

[Beetle-Kill]

Sorry, just reviewed your plan view of the structure. I saw those 9x12's being free-span, is this correct? Are they Glu-Lams, or LVL's?

 

[sksmass]

Sorry, just reviewed your plan view of the structure. I saw those 9x12's being free-span, is this correct? Are they Glu-Lams, or LVL's?

The 9x12's are supported mid-span. The north-south beam is supported by a lally column on one side of the masonary chimney and the east-west is supported by two columns evenly spaced. They are solid wood beams. House was built in the 40's.

 

[soupy1957]

The span of the hearth pad (base) below the stove is bigger than the stove, yes? Weight is dispersed even MORE with the size of the base.

Buy a lighter stove?

Seriously though.......I agree with the afore said info........if your floor is weak, (known flaws) then you have an issue. If not.........you'll be fine!!

-Soupy1957

 

[pyper]

The 9x12's are supported mid-span. The north-south beam is supported by a lally column on one side of the masonary chimney and the east-west is supported by two columns evenly spaced. They are solid wood beams. House was built in the 40's.[/quote]

So you have posts supporting the beams fairly near the stove then?

And there's no second floor, right?

I think you're on the right track -- put it in and see if you have a problem. In general, wood framing in floors is sized to resist bounce. You could probably have 2x6 floor joists and not worry about them breaking, but walking on them would be like walking on a trampoline. In fact, the kitchen that was in our house when we bought it had 2x6 floor joists -- two of them for an 8 foot width and a 16 foot span. Crazy. It used to be a porch.

 

[sksmass]

So you have posts supporting the beams fairly near the stove then?
And there's no second floor, right?

There is a column right near the intersection of the beams which is in turn really close to where the stove will go. There is a full 2nd floor. But I think I am just gonna go for it and see what happens. I had my wife jump up and down on the living room floor while I felt the ceiling in the basement. It hardly even vibrated. Now, I understand that is a live load and what I'm doing with the stove is adding a bunch of dead load, but at least it gives me confidence that everything is pretty tight as of right now.

 

[btuser]

Because the stove isn't in the center of the joist span but on the ends , I really wouldn't think it would be a problem for them either. When I remodeled my last kitchen "we" added an island with a 44 sqft granite countertop weighinng in at about 450lbs + stoves, cabinets, pots and pans ect. The original floor was 2x8" 16 OC and span 12.5'. I did the math and the dead load was only increased by about 12lbs/sqft. I sistered 4 joists w/ 2x10 for a total cost of about $50 JUST so I wouldn't feel the floor bounce. You don't have to go all the way to the end, just cut right before the wall and nail the heck out of them. If its a pain in your situation then I'd say forget it, but my island was in the center of the joists, not on the ends. Try bouncing on the floor near the end of the joists, then in the middle of the floor. One you can feel some give, while the other feels like cement!

How are the joist attached to the beam? Joist hangers or run past? I'm wondering about the bearing weight if they are indeed joist hangers. Its not a lot but there are different classes for different situations.

 

[sksmass]

How are the joist attached to the beam? Joist hangers or run past? I'm wondering about the bearing weight if they are indeed joist hangers.

The joists set right on top of the beam and the foundation, so there are no hangers.
I just took another peak through the dropped ceiling and am convincing myself that it'll be OK.

 

[madrone]

I'm not an engineer, but putting your numbers and a little guessing into a load calculator, I'm getting something around 50 lbs/square foot live load. Works out to about 1400 lbs. your hearth area can support. Basically, if you filled your floor space with stoves on hearths, it would still have available live load. Even at 40 per sq ft (the minimum) you won't hit the limit. According to the internets.

 

[BrotherBart]

After I put that six hundred and fifty pound insert in my fireplace in 1985 it was five years before I quit worrying about having a flaming box full of wood fall into my basement.

 

[golfandwoodnut]

Think about hot tubs on decks, that is alot more weight than the stove and you can have eight people inside.

 

[soupy1957]

Admit it...........you just had your "wife jump up and down" just to see her do it!! (lol)

-Soupy1957