Finishing a basement off. I am securing 1/2″ ply that’s floating on top of 1-1/2″ rigid foam insulation to a 4+” thick concrete slab. I will then lay another layer of 1/2″ ply running opposite. I’m thinking that I should put down a couple of tapcons on that first layer of 1/2″ to prevent movement.
Tapcon recommends a min depth of embedment in base material to be 1 to 1-3/4″. That would suggest I used a tapcon 3 to 3-3/4″ in length. Given that there’s little pressure effecting holding (pullout,side to side) is a tapcon 3 to 3-3/4″ long overkill?
Skippy
Replies
Concrete is not very strong in tension. If you embed the Tapcon only ½" or so you risk pulling a piece of the floor out. Even though your load may seem light, I'd follow the manufacturer's recommendation.
Skippy -- always reluctant to drill into a basement floor -- I always think of the floor as a reverse swimming pool -- keep the water out - if there is any way to use PL to adhere the sleepers, you should seriously consider. I have PL'd sleepers to the floor and poured quickset -- just a skim coat and it seeps under the sleepers and really locks them tight to a firm surface -- you'd be surprised about the ups and downs in a floor that seems level and the wood that seems dead straight -
The thing is I'm not using sleepers- just laying down rigid foam and ply on top. The tapcons would just be used to tack down that ply so it would shift.
Glue the foam, and then glue the ply to the foam. Only add fastners where the ply may curl up.
You may be able to get by with 1 to 1 1/4" embedment. You can try the PL Premium and then enough tapcons to pull the plywood flat to the foam, and then add your second layer of plywood. You'll really like the insulated floor that results from this construction method.
Billy
After reading the other posts, I agree that fastening the floor down is not necessary. Just screw the two layers of plywood to each other, you'll have a nice floating floor.
Wayne's method is what I would use. Was thinking the same way, and then there was Wayne's post.
Everybody does it with laminate floors all the time. The only problem would be if you wanted to set a wall on top of that floor. As long as it was not a load-bearing wall, it would probably work. On the other hand, the floor may depress more under just the weight of the wall as compared to the rest of the floor.
Bryan"Objects in mirror appear closer than they are."
Klakamp Construction, Findlay, Ohio - just south of the Glass City
Seems like an awful lot of work. You might want to consider using Dricore Panels. It does the same thing and you will have it down in a fraction of the time.
www.dricore.com
dave
I've been trying to use Dri-Core, but they don't stock it down here (southeast, even up to MD).
Lists as $6.82 per 2x2' panel on Lowe's website, but only can get it from Lowes special order at $8.14 / panel. No one's wanted to spend that much yet.
Forrest
Are you making a trip to Canada anytime soon? $6.49 per 2x2 panel. DriCore is a stock item in any Home Depot in Canada and most Home Hardware Building Centres. It is a vary popular product up here it wouldn't surprise me if every building centre across the country had it.
Dave
<Are you making a trip to Canada anytime soon?>
LOL! I could come back from the Fest with a couple hundred panels, and write it off as expense!
Forrest
Now your thinkin' !
Dricore in the Metro detroit area runs about $5.79 a sheet at HD. I've used it before in a small basement job, but I I doing something similar, I'd use the new product I've seen at Lowes or HD, which is rolls of dimpled plastic - just like the dricore bottoms, but just the plastic. You roll it out and seal the seams and then use normal T&G 4x8 sheets of plywood.JT
The other trouble with DriCore is that it doesn't breath...that's the best part of the rigid foam flooring. Insulation that allows the passage of water vapor.Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
dricor leaves an airspace for air to circulate..
<< dricor leaves an airspace for air to circulate.. >>
circulate to where? and what will cause it to circulate if it's sealed on all sides?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
>>The other trouble with DriCore is that it doesn't breath...that's the best part of the rigid foam flooring. Insulation that allows the passage of water vapor.And with doubled 1/2 ply over it?
May your whole life become a response to the truth that you've always been loved, you are loved and you always will be loved"
Rob Bell, Nooma, "Bullhorn"
A valid point. Still better than the plastic in the DriCore, no?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Last I heard, plywood wasn't rated as a vapour barrier.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Are you making a trip to Canada anytime soon? $6.49 per 2x2 panel.
Not around here, Doc. $8.15 per 2x2 at RONA. That's with my contractor's discount, too.
BTW, are you coming to the Fest? You're a lot closer than some of these guys.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
where is it?
Mont Tremblant. Take the 401 to Ottawa, then pick up the 148 east once you get across the river into Quebec. Turn north on the 323 when you get to Montebello and follow that all the way up to St-Jovite/Mont-Tremblant. We're five minutes from where the 323 hits the 117.
Click the banner below my signature for more info. That'll take you to the separate NorthFest website I set up to put all the details in one place.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Not exactly.You are going to get alot more insulation from 1 1/2 of foam than 1/4" airspace..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I did what you are describing. I used 1/2" foam on the cement followed by two layers of 1/2" ply. I didnt fasten the floor down to the cement and have had no ill effects after 2 years. I framed several walls on top of this and they are rock solid.
If you do decide to use the tapcon remember to blow the dust from the drilled holes or you will probably break every single screw before they get tight.
Sounds good- one concern
At some point I'm going to be putting a heavy wood stove on this floor will the foam compress and I'll get a dip in the floor at that spot?skippy
You will get some compression. I think you will have to put down a non flammable barrier under the stove, so perhaps this could redistribute some of the weight. I'm sure some of the pros will chime in.
The foam will support a decent amount of weight, but why chance it...lay a perimeter of sleepers under the stove to support it. Then insulate between and around the sleepers. It won't reduce your insulation much, and will offer lots of peace of mind. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Unless your code is substantially different from ours for woodstove installation, you need to have a solid 2" of concrete or other approved non-flammable material directly under the stove and for roughly two feet all around it, depending on its homologation rating. You definitely do not want to set the stove on top of a foam and plywood 'tea sandwich'.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I'm actually putting in a pellet stove but I do know I've got to look at the code- I will probably rely on the guys installing the stove to point me in the right direction.My main concern was having a valley as a result of the stove's weight compressing my foam/ply subfloor system.
Skippy
My main concern was having a valley as a result of the stove's weight compressing my foam/ply subfloor system
You will have a valley as a result of the stove's heat causing the foam to melt and collapse. A pellet stove is usually steel, not C.I., but it's still fairly heavy...and they put out an incredible amount of heat when they're blowing.
Whether the stove you want is heavy enough to cause noticeable flex in 1" of built-up plywood I don't know, but if you build your subfloor before you consult with the woodstove installers you're running a real risk of having to tear it out again.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....