A couple hearth pad questions

[KennyK]

I’m swapping out stoves in a week and a half (putting in a Fireview) and working on my hearth. The Fireview is going in front of my fireplace, rear vented to a liner through my chimney. I have have a prefab hearth that’s going on top of the existing fireplace hearth, which isn’t large enough to meet hearth clearance requirements. I’ve build up around and on top of the existing marble fireplace hearth with 1/2” plywood and two layers of 1/2” micore, and the prefab hearth pad is going on top of that base. I don’t really need all the micore for R value purposes, but had it around and needed the height to get the vent to the right height. My question is pretty simple, should I screw the two layers micore into the plywood or will it by stable enough with just the weight of the stove on top (as you all probably know, that sucker’s pretty darn heavy!). For that matter, should I screw the micore and plywood into my wood floor (part of it is on top of marble, but part is on top of a hardwood floor). I hate to screw into my hardwood floor but if the stability is a good idea, I’ll do it. Also, if I do screw this all together, I was thinking stainless steal screws - is that good or should I use something else. Thanks as always for the great expertise here!

 

[begreen]

Micore is soft so screws are not going to hold much. Will the whole plywood, micore, hearth pad sandwich be captive with a surrounding frame? If so, you probably don't need to screw it together. But if you want to put in some screws to hold it together then just screw it to the plywood in a few places. No need for stainless steel screws.

 

[KennyK]

Micore is soft so screws are not going to hold much. Will the whole plywood, micore, hearth pad sandwich be captive with a surrounding frame? If so, you probably don't need to screw it together. But if you want to put in some screws to hold it together then just screw it to the plywood in a few places. No need for stainless steel screws.

Good point about the micore being soft and screws not doing much. I’m making a frame by repurposing some old wood ceiling molding that is original to the house that I have on hand. It matches the esthetic, but isn’t particularly strong. I was planning on just nailing that into the edge of the plywood, but I could nail or screw it into the hardwood floor (I fear screwing it might split this 120 year old molding). I figure the weight of the stove should probably keep everything in place, and as mentioned before am a bit reluctant to screw or nail into the hardwood floor, but will do it if it’s the right move. Here are some pics of the sandwich and the molding edge (not done yet, just placed for photo and only on front, but will go around sides too). Would love your thoughts!

 

[begreen]

Planning will help mitigate concerns. If you want to make it one unit, use decking screws of the exact right length. to tie the sandwich together. One in each corner should do the trick. When framing the trim, predrill the nail holes to avoid splitting.