In getting everything prepped for my Woodstock Ideal Steel installation in about two weeks, I ordered this modular hearth pad that has three interlocking pieces (). It came and is pretty nice, simple so as to keep the focus on the IS, the powder coated steel has a good finish, and it has an R value of 1.03, which is more than double what the IS requires. The hearth pad is made from one sheet of Micore 300 covered with powder coated 16 gauge steel rounded over the edges of the Micore. The IS will sit on two of the three connecting panels (backs legs on the back panel and front legs on the middle panel), and if all goes according to plan, I will be able to set it up in a way that I can remove the front panel, which will be completely in front of the stove, during the months the stove isn't in use giving me back some floor space. I have three questions/concerns: 1) Will the weight of the IS pose an issue for this hearth pad? I asked the company that sold it, and they said they weren't sure, but knew it handled a 500 pound stove. The IS is about 650 without a load of wood. 2) The hearth pad will sit partially over my existing marble fireplace hearth and partially over the wood floor in front of that marble hearth. In order to get the wood floor height up to be level with the marble hearth, I was planning on using a piece of 1/2 to 3/4 inch plywood between the wood floor and hearth pad. However, there are some gaps in the Micore where the sections of the hearth pad connect (about 1/4 inch or so in two places where there is only open space below the steel), and I thought I could put another piece of Micore 300 between this hearth pad and the wood floor. The Micore 300 is 1/2 inch thick, and if I need a little more height I could put a piece of 1/4 inch plywood below the lower piece of micore. While this would be overkill for the required R value for the IS, it would give me the R value where the gaps are (giving me some extra peace of mind). My question here is, will the Micore 300 under this hearth pad be a fine base, as the plywood would have been? 3) Can I just put all of these pieces down without securing them into the floor and/or into one another? My thinking is that with the weight of the IS, these won't budge. My concern with securing them down is that the I don't want to mess up the wood floor in case I move this one day, and I don't want to conduct heat through metal screws if I were to use those to secure everything down. I spoke with the inspector and showed him a pic of this hearth pad. He said nothing about needing to secure it down, just that it needed to meet the R value requirement. Thanks!
2 screws on a several hundred pound piece of steel are not going to do anything to keep it in place if the shtf.
I wouldn't worry about securing it to the floor at all. With the IS on top of it, it would take some monumental force to just make things move about, in which case, I'd be more inclined to worry about anything above my head at the time. If you decide to secure it to the floor, I can't see an issue with heat transfer to the flooring through a few metal screws. The size of the hearth pad will allow for good heat dispersal. That being said, I also wouldn't worry about the small sections underneath where you say there is no Micore under the steel. The steel will transfer heat pretty evenly as well as the weight of the stove. If you main concern is to level from the floor the existing marble hearth, then either the Micore or plywood should be quite fine. You mention that the stove will not be directly on this section of the hearth pad, so the R value would only become an issue if burning coals or chunks of wood come out of the stove and come to rest on that section of hearth pad. Even if that were to happen, as long as the problem is corrected in a timely manner, the existing R value of the hearth pad should offer plenty of protection. Someone with more accurate information may refute my thinking on the subject, but those are my thoughts on your situation.
I'm easy 6 foot and 225 I tripped and fell into my IS, daughters stuff on floor.. I think I'm as tough as steel, they stove did not dent or move a fraction!!
Thanks Chaz! Yeah, I don't think I'm going to worry about securing it to the floor. One clarification - the 1/4 inch gap in the will be under the stove (there are two places with gaps, one will be right under the body of the stove and the other will be a few inches in front of the door). This was my concern for meeting the hearth pad R value requirements of the IS. You make a good point about the pad dispersing the heat and weight. I still wonder about the strength of micore, both in the pad itself, which will probably be fine, and more so in putting an extra piece of micore under the hearth pad and if that will hold up. Plywood is very strong - I'm wondering if anyone knows how the micore will hold up under the weight of the IS. I did some looking online and am having a tough time finding specifics. Thanks!
I wouldn’t be surprised if micore can take a lot of weight. They put rigid foam insulation around the same thickness under concrete slabs, then park cars on it.
BeantownBurner I think you're worrying too much about the weight of the stove. Here are some stat's I've looked up. The hearthpad info from amazon.. Lookup of Micore300 Sorry about all the whitespace.. It is important to note the Janka Ball test value of 55lbs. It means it required 55lbs of force to indent a .444" steel ball halfway into the material. If you factor that out to a couple of inches, (the legs of the IS are 1.5" square, so that's 2.25 sq inches that the weight of each foot is applied over) the force required for compression increases dramatically, then when you apply the 16ga steel atop the Micore300 substrate, once again you are increasing the carrying capacity immensely. Janka Ball test.. The Janka hardness test measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an 11.28 millimetres (0.444 in) diameter steel ball halfway into a sample of wood. This method leaves a hemispherical indentation with an area of 200 mm2. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. Balsa wood lists at .. Balsa[10] 70 lbf (310 N) Softest wood ever measured: a single, unusual sample of Balsa[10] 22 lbf (98 N) So, while the Micore300 is not the strongest material on the market, it along with the steel top should be more than adequate for your installation.
Chaz, as we say in Beantown, "you're wicked smaaaaht!" Thanks, this why I come here with these questions, so you all can help me put my concerns to rest! Much appreciated!
Note to above post, force is measured in lbf so the weight calculation has to be corrected in comparison to the .444" steel ball. By my calculations it should take roughly 10 lbs of weight in order to indent the steel ball halfway into the Micore300 material. While this is not a lot of weight in and of itself, it once again needs to be taken into account that the weight of the stove is distributed across 4 areas of contact that measure 2.25sq inches each. The rough calculation is 5times more area for the feet of the stove vs the ball, and if one works the numbers it comes out to roughly 200lbs of carrying capacity of the substrate alone. Nearly 1/3 of the weight of the stove. Once you add the 16ga steel, more load can be applied without noticeable compression. I'm sure there are faults in my math on this, I am NOT a design engineer, I'm only coming from a laymans point of view.
It would also help to know the hardness of the 16ga steel used as the top layer for the hearth pad, as that directly correlates to the carrying capacity of the steel as it applies to load rating. The harder the steel, the more the weight would be distributed over a larger area before any deformation or buckling would occur. Very hard steel tends to break/shatter rather than bend. One would be quite willing to accept that it is a very mild steel, as hardening would add considerable cost with no true benefit. Even so, I would imagine that the steel should easily be capable of carrying well over 100lbs of weight per square inch, and once again we are talking about 9 sq inches of footprint to carry the 650lb load of the stove. The steel should easily be able to distribute the stoves weight out across the Micore substrate, which no doubt is why they included it. If it were not required to help distribute weight, it would be an unnecessary expense.
