I know this has been discussed often but can I ask a couple of questions re finishing off a basement-specifically how to handle flooring.
I have about 9′ of ceiling height to work with. The slab is not insulated
This is my plan-
Secure 2X4 pt sleepers wide side down either 16″ or 24″ OC
1″ XPS rigid foam insulation between sleepers
3/4″ T&G ply glued and nailed
Any additional interior partitions would be built on top of this “deck”
Questions-
Should there be a vapor barrier under the 2X4 sleepers?
Rather than insulation between sleepers should I put down insulation first and then run the sleepers on top? If so, do I “float” them or should they be secured to the slab?
I’m going to assume that what ever system I use on the floor would work in the same way on walls (with studded wall and drywall instead of ply)
I’ve looked at the various “systems” by Corning and others-prefer the low tech method above.
Thanks for the help.
Skippy
Replies
Secure 2X4 pt sleepers wide side down either 16" or 24" OC--- why not layout the sleepers so you can fit a 24" wide piece of XPS between each sleeper?
1" XPS rigid foam insulation between sleepers---- Why not use 1 1/2" XPS?
3/4" T&G ply glued and nailed--- I prefer screws to nails.
Should there be a vapor barrier under the 2X4 sleepers? Probably not, Is there a vapor barrier under the slab? Get a copy of JLC's June '07 issue, p. 61 "Testing for Moisture in Concrete Slabs", pay close attention to p.65 sub-heading "remediation".
Rather than insulation between sleepers should I put down insulation first and then run the sleepers on top? If so, do I "float" them or should they be secured to the slab?
No
I'm going to assume that what ever system I use on the floor would work in the same way on walls.
True, but follow the above suggestions..... Oh and NEVER ####-u-me, you what that does! :) (makes an #### out of you and me)
Geoff
Thanks for the suggestions-I do not have a vapor barrier under my slab- I'm concerned that if I put a vapor barrier on top of the floor now I'll get condensation between the slab and the barrier.I did not know they made 1.5" foam insulation but will use that.Did not understand your last line?
Skippy
Skippy,
looks like I offended the powers that be, and they edited my line. I said never assume, it makes an a## out of you and me. I guess I shouldn't have assumed it was O.K. to say that! :)
As for the 1 1/2" foam, If you can't get it in your area, just combine 1" and 1/2" pieces.
<I do not have a vapor barrier under my slab- I'm concerned that if I put a vapor barrier on top of the floor now I'll get condensation between the slab and the barrier.>
The author in the article I mentioned has similiar concerns(and Justin mentioned this too). I would do the moisture test and then make your decision from there, maybe using a sealer(as mentioned in the article) instead of a poly vapor barrier would suffice,also exterior mitigation might help(grading, gutters,and directing downspout outflow away from the house) all depends on what your test results show.
Geoff
Forgot to mention, you might consider using Drylock on the walls prior to applying the foam, does an excellent job of sealing against hydrostatic pressures.
Edited 7/11/2007 5:13 pm ET by Geoffrey
Thanks for info-Re drains etc.- spent lots of money when I did the foundation on footing drains, 6" compacted stone under slab and $$$ on a waterproof membrane on exterior wall. I planned to finish basement from the get go and take advantage of a walk out basement. I've let a year pass from completion of first floor construction, I've kept a close eye on the floor and walls and there appears to be "no visible sign" of moisture.I've read the JLC article. My main concern is moisture vapor migrating through the foam/ply and then into hardwood or carpet finish floor. Thus my question re vapor barrier between slab and foam.Thanks
Skippy
Skippy,
considering all of your fore-thought on the drainage and wall protection(from water) I'm really surprised to hear you have no VB under the slab!!It's such an inexpensive step to prevent water intrusion from under the slab. Given all your work though, I would think you could skip the VB on the slab and allow what little moisture you do get to escape up thru the floor system, rather than being trapped under the VB.
The best practice would still be to conduct a moisture test so you know what your dealing with in terms of moiture intrusion from under the slab.
Geoff
My floor guy convinced me that the VB under the slab was not necessary. I'm assuming it was really because it would have made for more work for him. I remember him saying something about the VB not allowing for the concrete to drain/set up properly. But hey I got a good price.I will try the moisture test and go from there.Thanks-Skippy
on the walls you should run the all the foam then frame a plumb true wall in front of it.
The 2x4 PT sleepers will go in wet, and though they won't "rot" they can still support the growth of mold. They also create areas of thermal bridging (they ain't good insulators), and will cost more money than just laying rigid foam on the slab, then plywood over that anchored through the foam and into the slab.
Don't put in a vapor barrier. Any moisture that does pass through the slab should be handled by the HVAC system, not blocked by barriers.
For what it's worth, I agree with rigid foam on the walls, then plumb stud framing in front of that.
Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
Thanks for the help-QuestionIf I run ply over the foam recommendations for securing it to the slab? Hilty or concrete screws sounds like an awful lot time/effort.Skippy
Check out Andy Engels article in the mag about 18 months ago. He put foam down in full sheets (no sleepers) and built his finished basement on top of that. He got most of the info from Building Science Corp. About 6 months later Mike Holmes did it on one of his tv shows and passed it of as his method.
Have a good day
Cliffy
<< About 6 months later Mike Holmes did it on one of his tv shows and passed it of as his method >>
Are you serious? What a crock... I've never seen that show, but I think I've heard of it. When does it come on? what channel?Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
It is a Canadian show. I let Andy Engel know of this plagiarism months ago, he did not seem too concerned.
Holmes on Homes is on thursday nights on HGTV Canada. Reruns run daily right now I think at 6 pm. You may have seen a few threads here with us bitching him out. Google Mike Holmes and you get his shows web site.
Some yanks (Yanks used as slang only not disrespectfully, I usually refer to Canadians here as Canucks)on this forum watch Holmes on Hmes on your channels but I don't know where or when. He comes in and bails out people who have been scammed by contractors who buggered off with the money. Sometimes it is a good show but Homes' attitude rubs a few of us the wrong way.
Have a good day
Cliffy
You could also consider not putting sleepers at all if the existing slab is relatively flat. Lay down 1-inch or 1-1/2 inch rigid over the whole floor and then install 2 layers of 1/2" or 5/8" plywood - the second layer at a right angle to the first. The whole floor would float.
Would you put vapor barrier on top of slab ?
Skippy
Well, there's a lot of variables for your project I don't know about and finishing a basement is a sure-fire way of starting a heated debate when it comes to discussions on construction techniques. But, I would agree with Justin though, skip the VB, allow the vapor drive to go where it wants and pick it up mechanically
I've considered this floating floor option as well. I've got another basement coming up in the next month or so, and it's about 1,000 sq. ft. --- I'm not looking forward to all that Tapcon drilling...Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
The last basement we did was for a home theater. Box within a box kind of thing. Working with an acoustical engineer, we came up with a floating floor design. These little 1/2" rubber waffles were screwed every so often to a sheet of 3/4", flipped and put rubber side down then a second layer of sheets at right angles was laid over. The walls sat on top of that. Worked very well.
hmm, that sounds pretty cool...what were the rubber things>?
I'm really starting to lean towards using sleepers with foam between them...maybe I'm just feeling lazy, or maybe that truly is the smarter way to go. Justin Fink - FHB Editorial
Your Friendly Neighborhood Remodelerator
http://209.200.80.33/html/SUBMITTALS/NEOPRENE%20MOUNTS%20AND%20PADS/SuperW.pdf
Super W! You can get these through grainger - cut 'em up, lay 'em on, flip it and go. It really did work out to be a good system.