Anybody ever rip out a hearth from plywood subfloor?

[fire_man]

I just put down a deposit on the new Woodstock stove! The problem is we still don't know clearance requirements and therefore hearth size. I may just opt to extend the hearth size by adding to it, but if the R value needs to increase for the new stove I will need to completely replace it.

I installed the hearth - it's 1/2" cement board on top of a layer of Thin Set Mortar, and its screwed down onto a plywood subfloor. There is a layer of brick (again mounted with Thin Set Mortar) on top. Its all surrounded by hardwood floor (which I just installed).Bummer I wish I just made everything much bigger!

Has anybody ever tried to demo out such an installation? Seems like it would be hard to get to to the screws through the Thin Set, and how much damage will there be to the plywood when I try to chisel out the cement board from the Thin Set? :bug:

 

[tfdchief]

Unfortunately, there is little way to know the answer to your questions until you tear into it. Did you install the hearth that is there? Knowing how it went in will help and it sounds like you do. You will probably have to just use a crowbar and chisel and pry pieces up. I doubt you are going to be able to take individual screws out. Sorry, but demo is usually trial and error.

 

[bpm44]

Any reason you couldn't just pop the bricks off, expand your area of plywood/durock combo adding more Durock on top if you need more r value (screwed down but bedded in a thinset product like Megabond) and then re lay new bricks in a bigger footprint?

I think avoiding messing with the screws holding the existing down will save you a lot of grief.

 

[fire_man]

Any reason you couldn't just pop the bricks off, expand your area of plywood/durock combo adding more Durock on top if you need more r value (screwed down but bedded in a thinset product like Megabond) and then re lay new bricks in a bigger footprint?

I think avoiding messing with the screws holding the existing down will save you a lot of grief.

I agree, hate to mess with the screws. Only problem with adding more Durock for more R value on top is it messes up total height of the floor. That means messing with the stainless steel flu liner. That's why I like replacing the 1/2" cement board with micore

 

[fishingpol]

If you rent a demo hammer with a wide chisel blade, it should go through the cement board without a problem, causing minimal damage to the plywood. As you hit screws, go around them and pull them with a crow bar, or cut them flush at the plywood with a sawzall with a metal blade. You could also use a pair of vise-grip pliers to extract the screws as at least a 1/4" of the screw should be exposed. You may also find the vibration from the demo hammer may loosen some of the thinset as you go. Now, if you were trying to remove the screws from the plywood, that would be a real PITA. Any damage to the plywood would be just the surface, and that can get covered with thinset again. Let the tool do the work for you and protect the hardwood.

I hope that new stove works out for you!

 

[My Oslo heats my home]

Considering the reason for the floor protection is for embers and not so much r-value, I kind of agree with Keeper with making a few minor changes and expanding what you already have. Your greatest r-value will come from insulation under the floor not additional layers of a solid material. If you can salvage most of what you already created and make a larger non-combustable area for your new unit make that plan A. Plan B, dynamite.