Improving R value of hearth

[faultymechanics]

Hey all,

Back again with hopes and prayers that this is the year we finally get a functioning wood stove.

I had posted a thread similar to this before but with a different question so I figured I would keep this brief.

I want to replace my insert with a new woodburning insert. Our current hearth has plenty of space for an insert, however, the problem is the builders of our home back in the 1930s left the wood form under the heart which is a big no-no.

My question is this, is it going to be easier for me to just pull up our current tile hearth and lay down some micore, then recover with tile and make a lip. OR do I try to remove the old wood form from under the hearth.

I'm thinking the micore will be the easiest route and I'm thinking the lip wouldn't be too gigantic from the added material but I would love some input. If I go with removing the form I'm guessing I'd need a structural engineer to come in and confirm I can remove the form without risking the integrity of the house? Then I would have to actually remove that old form that is perched above my pellet boiler.


Photos below:

 

[begreen]

I think it's unlikely that an engineer would be required to approve the form removal.
Previous discussion:

Overheating stove in Hearth

Just had a company tell me they don't "suggest" installing their freestander in the fireplace because it could overheat due to being somewhat enclosed. Anyone ever heard of this? I feel like they're probably just covering themselves liability-wise and that temps can be regulated with a...

www.hearth.com

 

[jalmondale]

What R-value do you need? If it were me and I weren't too attached to that specific tile, I'd probably just leave the existing tile, add a layer of micore, and then re-tile it with new tiles (tile is usually pretty thin, so this shouldn't wind up being much thicker than if you remove the one tile). I did a similar hearth expansion, and three layers of micore, one layer backer board, and tile was just about the perfect thickness to put a standard door casing trim around the whole thing (I stained it to match the floors). I think it looks nice without being intrusive, and I've yet to stub a toe or trip on it.

That said, are you limited on fireplace opening height? If you've got a couple inches to play with, that's one thing, but if the insert is running up against the limits of the fireplace already, you might have to go with removing the forms.

 

[EbS-P]

Do you have an insert picked out? Personally taking out the tile would be my choice. The job may take a bit longer but you would get a chance to pick new tile. Demo above your head is never fun and working around pipes isn’t either.

 

[faultymechanics]

What R-value do you need? If it were me and I weren't too attached to that specific tile, I'd probably just leave the existing tile, add a layer of micore, and then re-tile it with new tiles (tile is usually pretty thin, so this shouldn't wind up being much thicker than if you remove the one tile). I did a similar hearth expansion, and three layers of micore, one layer backer board, and tile was just about the perfect thickness to put a standard door casing trim around the whole thing (I stained it to match the floors). I think it looks nice without being intrusive, and I've yet to stub a toe or trip on it.

That said, are you limited on fireplace opening height? If you've got a couple inches to play with, that's one thing, but if the insert is running up against the limits of the fireplace already, you might have to go with removing the forms.

I would love to see a photo of what you've done, if that's possible. If I do go the tile route I will probably just pull the tile as it wont be too much work, I have the time and would prefer keeping the lip as small as possible. I have plenty of vertical space in the firebox which is great. The WinterWarm insert I have was already huge and I have probably another 3-5" of space above that if I recall correctly. Been a while since I last measured.

Do you have an insert picked out? Personally taking out the tile would be my choice. The job may take a bit longer but you would get a chance to pick new tile. Demo above your head is never fun and working around pipes isn’t either.

Originally we were looking at the Osburn Matrix 2000, anything similar to that would be perfect. Personally I would love one that extends out into the room a bit, however the hearth extension (Tile) that is currently there is just barely 16" now. I suppose if I'm doing this job I could always extend it a bit further, there are burn marks on the wood floor in front of the extension from the previous owners.

If I can safely remove the current insert and block off the chimney so I don't get critters, junk and a cold draft blasting into my house, time will be of no concern for this project. I also have to make sure my cats and dogs can't sneak into the fireplace somehow, that's probably my biggest concern at the moment, blocking things off when I remove the insert.

Is removal of old units a service sweeps provide even if they aren't replacing it? I don't have an appliance dolly or anything to get the insert out, suppose I could rent one and then take the insert to the dump?

 

[EbS-P]

I would love to see a photo of what you've done, if that's possible. If I do go the tile route I will probably just pull the tile as it wont be too much work, I have the time and would prefer keeping the lip as small as possible. I have plenty of vertical space in the firebox which is great. The WinterWarm insert I have was already huge and I have probably another 3-5" of space above that if I recall correctly. Been a while since I last measured.


Originally we were looking at the Osburn Matrix 2000, anything similar to that would be perfect. Personally I would love one that extends out into the room a bit, however the hearth extension (Tile) that is currently there is just barely 16" now. I suppose if I'm doing this job I could always extend it a bit further, there are burn marks on the wood floor in front of the extension from the previous owners.

If I can safely remove the current insert and block off the chimney so I don't get critters, junk and a cold draft blasting into my house, time will be of no concern for this project. I also have to make sure my cats and dogs can't sneak into the fireplace somehow, that's probably my biggest concern at the moment, blocking things off when I remove the insert.

Is removal of old units a service sweeps provide even if they aren't replacing it? I don't have an appliance dolly or anything to get the insert out, suppose I could rent one and then take the insert to the dump?

To make sure you have all the clearances and r values you should probably just pick an insert and build to to those specs. I have the Drolet 1800i. It sticks out a bit. To be honest I like the flush insert look. Just come up with a backup power solution. My plan is a computer batter backup. And then My generator if needed.

 

[faultymechanics]

To make sure you have all the clearances and r values you should probably just pick an insert and build to to those specs. I have the Drolet 1800i. It sticks out a bit. To be honest I like the flush insert look. Just come up with a backup power solution. My plan is a computer batter backup. And then My generator if needed.

I actually have a couple spare UPS' that I keep charging in the basement. Are the fans loud on those flush models? I like the idea of silence whenever possible.

 

[EbS-P]

On low where I’m guessing it’s pretty quiet. It has a different blower that my 1800 and it’s almost imperceptible on low. Anything will noisy on high but it’s a 90 cfm blower so it shouldn’t be too bad. Search the forum actual owner Experiences.

With no ash lip it will suck a lot into the blower if you open the door with the blower on. Not a great choice for 24/7 burning IMO. I’m guessing the other Osborn that stick out used the same blower mine does and it has an ash lip and draws air more from the sides.

 

[jalmondale]

This is what mine looks like - the lip is 2 1/4" high. It's just over R 3, which is probably more than I'll ever actually need, but it worked out with the size of the trim and the amount of micore I had.