Yuck particleboard. You have my sympathy. We just went through the exact same thing. We took bids from several flooring co's and contractors. In our opinion, the best solution was the following, and that's what we did. The floor planks are just now being installed and look great: 1. Remove the particleboard using a skilsaw and crowbar. Also remove any felt/paper below it. This took 2 guys less than an hour per 100 square feet. 2. If your subfloor is less than 5/8" plywood, add an additional layer of 5/8" CD/X plywood. Lay it down in the opposite direction of the existing subfloor, glue and screw it, probably into the joists (ask someone about that). We used exterior fir plywood, not advantech or OSB or interior underlayment. This took 2 guys about 3 days to do 1000+ square feet. 3. Install the hardwood planks the standard way. Our contractor said no need for any vapor barrier, for us. I get the idea from experts that paper may have been more useful back when subfloor was 1x6 boards -- it would have given a smoother installation surface and also prevented dust from falling through the floor into whatever was below it. I personally hate particleboard so I advocate removing it. The time-consuming aspects of the overall job are installing the additional plywood and the floor planks -- removing the particleboard is comparatively not much work. If you leave it in, you will have to put at least 5/8" ply on top to conform to wood floor manufacturers' warranty requirements. And that will lower your ceiling height, which may be an issue if you're in a 1960s/70s era house. Plus, a particleboard sandwich on ply just doesn't seem very stable (or nutritious). I'm no expert but I trust my contractor and he has a pristine reputation. Hope this helps!

Kristine, that's a thought - ours was is made by Weyerhaeuser about 12 yrs ago, and I think it's just been renamed from SturdiWood Edge Gold we have to the current product, Ilevel Edge Gold, but their website talks about this Ilevel OSB being moisture resistant so that it will hold up to the weather during construction delays. Considering Weyerhaeuser is in my backyard and I am in the rainist city in the nation, I am guessing my OSB may have more moisture resistance than I am giving it credit for. What is your underlayment? The guy at the flooring store who used to be an installer said it's just roofing paper. Is that what yours is? Olga, if you have easy access to photos of your floor, I'd love to see it! Mine will also go in the entryway, kitchen, dining room, and powder room.

And just to be helpful (probably not...but here we go), a 5" wide hardwood needs "glue assist" with a nail in place install. So there must be some gluing going on. The extra cost of the sound reducing membrane isn't what is driving the cost up. It is the two layers of glue (yes the acoustic underlay must be glued and then the hardwood glued over top = double stick) and the extra labor to do everything "twice". Twice the labour, twice the glue = twice the budget. A glue down hardwood is the most expensive form of hardwood install we have. Nailing is the cheapest. A floating method is between the two. A glue assist for a wide plank (ahem...5" ranks as wide plank = needs glue assist) is more expensive than a float...but not as expensive as a full spread glue down install. Check to ensure the quote for the nail down includes the glue assist. If it doesn't, then they could be missing a step. The 1/4" cork underlay (from iCork Floor) = $0.66/sf. Some shipping costs (maybe $0.45/sf) brings it to about $1.10/sf for the cork. The other $5/sf is the glue (assume $1/sf per layer = $2/sf) and the extra labor to do all this gluing. The material only adds $3/sf. The labor is the other $3/sf. $3+$3 = $6/sf for this install. If you MUST HAVE acoustic insulation + solid hardwood, then you must have the extra $6/sf. There is a possible solution: floating hardwood. Yep. Float the hardwood (very few solid hardwoods are allowed to float...so you need to look at engineered for this) and you FLOAT the cork underlay. No glue = reduce the material costs by $2/sf. Since floating a hardwood is just SLIGHTLY cheaper than a "nail + glue assist" install, the cost of labor for the floor itself won't change. Switch to an engineered hardwood that can float and then add the 6mm cork underlay. It will add $1 - $2/sf to your current quote. My calculations indicate you have 2500sf of flooring. The cork underlay will only add $2500 to your material costs. Compare that to $15K for the double stick total. The solution = floating engineered hardwood. You can have your cake and eat it to.

So here' the deal. I've investigated sound transfer because I used to sell cork flooring and underlayment products. Here's what I know: 3/4" wood = 5 dB of noise reduction Regular "pink" R19 insulation = 5-10 dB of insulation (IIC and STC) 6mm of cork (1/4") = 11 dB of impact and airborne (Delta IIC rating) noise reduction 12mm of cork (1/2") = 22 dB of noise reduction (Delta IIC rating) Consider: a human conversation at 3 ft apart = 60 dB. Your set-up so far = 5 dB + 5 dB + 10 dB = 20 dB of reduction Your set-up is considered 'normal' for a family home. Nothing more..nothing less. If you intend to glue down the hardwood, I would recommend 6mm or 12mm cork for underlayment. The cork can be glued directly to the substrated (plywood) and then the wood floor can be glued to the cork. This is called a double stick. If you are planning on nailing down, you can sandwich the cork between the 2 layers of subfloor. Do NOT pierce the cork with metal. Metal conducts noise (aka...phone lines used to be made of metal) over distance. If the entertainment room is in the basement, this is easier. You only have to work with 5 of the 6 sides of the cube. If the entertainment room will be sitting ON the hardwood (as in the theatre room is UPSTAIRS) then this just got more difficult. Now you have to mitigate all 6 sides of the cube to reduce noise transfer from one area to another. And remember: the low-frequency sound emitted by theatre sound systems can be a BEAST to deal with. This is different from regular airborne transmission. Theatre noise usually incorporates HUGE amounts of volume throughout the entire human acoustic range 20Hz - 20,000Hz. Regular human vocal sounds (airborne sound) sits in the 300 - 800Hz range. This is what most "regular" insulation deals with. Green Glue, Mass Loaded Vinyl, Rubber and cork all deal with the 500 - 2,000Hz range quite nicely. The problem comes in with the lower stuff (20-300Hz) that you FEEL in your chest but don't recognise as "hearing" it. These deep vibration noises are often used in the movie industry to bring about the unnerving sensation of "tension" or "being watched" or any other form of sensation common with thrillers, suspense or horror movies. The UPPER range (the extreme range of violins, piccolos, cymbals like high-hats, etc) are also a problem. Not many products on the market can deal with high pitched noises (4,000Hz = most annoying noise to the human ear = finger nails on a chalk board = highest note in the piccolo's range). These "bothersome" sounds are rarely found in the day to day running of a household. Talking on the phone, cooking a meal, typing on a keyboard, walking down the stairs are all noises that are either intermittent (foot steps) or of such low volume (not very loud) that normal insulation practices are considered adequate. The problems are magnified when these problem noises are PROLONGED or of such VOLUME that they overwhelm the acoustic system....as would be the norm for a home theatre or home entertainment system. In otherwords it is SOOOO much cheaper to assume your theatre room is GOING TO BE A NUISANCE and mitigate it to the point of financial hardship. Do everything you can think of to keep the room as isolated as possible. How much irritation are you and your family willing to put up with? If your love of a theatre system out-weighs your irritation, then you are just fine. If you WANT more insulation and you EXPECT more noise control, your set-up won't do a thing towards what you want or expect.