Crawlspace is flooded, heater is dead. Woodburning insert is... damp?
November 18, 2015 4:54 PM   Subscribe

This is a very simple question I guess, but that's the long and the short of it. Crawlspace is flooded, which killed our central heater. Our cast iron insert is damp and I'm unsure as to whether we should burn anything in it.

We're surrounded by water, which is slowly but surely going away. But we won't be able to have our crawlspace pumped until it recedes (hopefully tomorrow?). This effectively puts our heater out of commission for the foreseeable future. We don't have a fireplace but we do have a wood burning insert (like a cast iron stove surrounded by brick) that will probably warm up the entire house nicely considering where it's placed. But we haven't used because we really don't have a place to store any significant amount of wood just yet. That's something we have been trying to fix but it's not like we have the funds nor the wherewithal to make a space for wood storage appear, and you can't just store it on the ground -- because hello, there's a good six inches of water everywhere - minimum.

Anyway, we can get some wood to last us for a couple of days (not cost effective, I know... but what can you do?). However, I just checked the insert and the bottom is damp, wet to the touch. Whether this is from the water underneath or the chimney leaking -- your guess is as good as mine guess. Since the rest of the house is dry, I'm guessing that the chimney leaked.

So my question is simply... Is it okay to start a fire in it this insert? Google was not helpful in this regard.

It's not raining anymore, but I'm worried that there might be damage to the chimney or something. It's not freezing here yet... forecast is for low 40's tonight. So we can make due with sweatshirts, socks, and blankets, but we'll probably need this insert in the near future if this is what the winter holds for us.

Replacing the insert is not an option.
posted by patheral to Home & Garden (14 answers total)
Response by poster: Sorry, I forgot to mention that the bottom of the insert appears to be stone while the rest of it is cast iron. The stone is wet to the touch.
posted by patheral at 4:57 PM on November 18, 2015

If the chimney is clear, I don't see a problem. Are you worried the cast iron will crack from the dramatic change in temperature? Or that the cast iron has been rusting away for years and that this will put something toxic in the air??

Please outlying your concerns. If it looks sound when you check out with a flashlight, and you have a fire extinguisher if things go horribly wrong, you should be OK.

In general (and i'm sure you know this) the heat from the fire sends the smoke up the chimney. If the smoke does not go up the chimney, put out the fire immediately.
posted by jbenben at 5:02 PM on November 18, 2015

I'd say go ahead-- the heat will drive the water out of itself. You should expect the heat output to flag at first while it goes into the water's phase-change, and of course you should ventilate to deal with the steam/humidity this may cause, but I don't think the iron or stone (or you) are in danger from getting a fire going here. Better to get the iron dried out anyway.
posted by Sunburnt at 5:04 PM on November 18, 2015

Response by poster: I'm worried about two things, that the heat will make the wet stone crack, and yes, that there might be rust damage in the chimney and it'll all come crashing down if we start a fire in there.
posted by patheral at 5:05 PM on November 18, 2015

The problem with never having used it is that you don't know that your chimney is in any condition to be used. There could be a bunch of creosote buildup that could catch fire. It happens sometimes when chimneys have not been inspected and cleaned if necessary.

Is it likely? Not really, but in this case electric space heaters might be a better way to go. It wouldn't do to have an attic fire at a time when the fire department would have trouble getting there to put it out.

(I'm assuming this isn't a brand new insert and chimney, but is in fact left over from a previous owner)
posted by wierdo at 5:05 PM on November 18, 2015 [2 favorites]

Chimney sweeps are some sort of a known scam, so you want to get a reliable contractor or similar to inspect the chimney (probably with a camera!) when the weather breaks.

It's hard to say if you have rust. If the entire thing is encased in brick, I would build a small fire first and see how it goes for a few hours... YMMV.
posted by jbenben at 5:11 PM on November 18, 2015

Without knowing the condition of the flue and chimney, do not use this insert.

Carbon monoxide kills many people every year and I would not risk it.
posted by littlewater at 5:15 PM on November 18, 2015 [1 favorite]

Buy a carbon monoxide detector if you don't have one. Build a small, supervised fire and go from there. The dampness is not important. It may mean you chimney has had rain water in it. That is quite unlikely to be a problem, though I do recommend drying it out slowly with smaller fires.

Is it possible that something is wrong with your chimney? Sure, but chimneys are pretty simple and problems aren't that likely. I'd certainly take this risk.
posted by ssg at 5:46 PM on November 18, 2015 [1 favorite]

The stone is likely wet to the touch due to condensation, not a leaky chimney. It's less likely to crack if the rock isn't porous but any heat could make it crack. Having it crack would not necessarily be a big problem and if the fireplace has already been used by others it should be okay as long as the chimney is drawing.
posted by lester at 6:52 PM on November 18, 2015

I'm inclined to say that the stove probably won't heat up all that fast, such that the brick surround would dry out and heat up just fine at a non-cracking pace.
posted by rhizome at 7:42 PM on November 18, 2015

If it's an insert then it will (or should be) lined with firebrick. That's probably what you see on the bottom. If you've experienced a big storm with blowing rain, it's possible that rainwater could've found its way down the chimney.

I'm worried ... that there might be rust damage in the chimney and it'll all come crashing down if we start a fire in there.

You can almost certainly set that worry aside. Chimney liners rated for wood stoves are stainless steel.

As Wierdo wrote awhile back, the main risk you'd be taking is that a previous resident might've burned a lot of damp wood in the insert and thus given the chimney's interior a heavy coating of creosote (condensed smoke), which is flammable and can burn at very high temperatures. If your fire managed to ignite our hypothetical creosote, you'd have a chimney fire. If the chimney itself were in poor condition, that could become a house fire. Such a disaster isn't all that likely, but the consequences could obviously be dire. Without ever having done a careful inspection or really understanding how wood stoves and chimneys work, I wouldn't risk it.
posted by jon1270 at 8:30 PM on November 18, 2015

Best answer: There may be scammy chimney guys, but calling a well rated chimney guy to look at a chimney that has never been used by you before is just good practice. Chimney fires are no joke. Angie's list is a good place to look for a decent chimney specialist.
posted by rockindata at 3:23 AM on November 19, 2015

As for things being sounds like your whole world is damp- that won't hurt anything, but it will take a little while longer to hear things up.
posted by rockindata at 3:24 AM on November 19, 2015

Response by poster: I just wanted to let y'all know that I didn't use this insert because of concerns... I had a chimney company out today (certified) and they recommended against using it at all. They said that there have been several chimney fires in the past and the seals are all but gone, the outer pipe is "blown" and that's why there's so much rust. They pointed out that the black I'm seeing on my mantel isn't soot but char. In other words, it's a dangerous little insert someone probably slapped together here and probably not safe for use.

I'm glad I didn't risk it.
posted by patheral at 12:45 PM on January 19, 2016 [2 favorites]

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