Basements need to be dry or at least not accumulating water before you ever start any basement flooring project you need to first do some basement flooring preparation. I wouldn’t even think about it without knowing first whether I have a “leaky” problem that needs to be looked into. The trick is, sometimes you can’t even really tell if you have a moisture problem. It is absolutely essential that you fix any problems with dampness or resolve any problems with leaks before you start with basement flooring. After you have done this, wait a while and ensure that the problems have disappeared.
An upfront basement flooring preparation strategy is critical even if you feel like you don’t have wet basement. Humid weather can run rampant and destroy valuable basement flooring. Not only that, who’d want to put the effort and work into something only to see it be destroyed a little more everyday. Humidity a killer, because it causes condensation that forms from the cool floor surface temperatures. A good basement flooring preparation strategy will help you in resolving that musty basement smell.
A method that’s gaining quite a lot of attention for basement flooring preparation is the use of a rigid extruded polystyrene foam board as a basement foam board for quite a few different reasons. First, their extruded skin and closed cell structure provides for outstanding moisture resistance. They are strong because the foam board has been compacted producing very high compressive strength. Extruded polystyrene foam board makes for an excellent polystyrene foam subfloor, is relatively easy to work with, and it provides for excellent thermal performance that offers maximum insulating value. This makes it highly suitable for most common residential and commercial applications as well as for basement flooring preparation.
To begin with this basement flooring preparation method, you will need to start with 1.5 or 2 inch thick extruded polystyrene foam board. Get enough to cover your entire basement floor. They come in 4 foot by 8 foot sheets and depending on the brand and rating you get can range anywhere from $15-$30 a piece with an average floating around the $20 range. Shape that in over your concrete into your basement flooring. You want a good tight fit or else you will probably need to tuck tape all the seams. Then you can recreate your subfloor over the top of this foam board with a minimum of 5/8 inch plywood. Lay the plywood down directly on top of the foam board. Now go back and pre-drill some holes through it all into the concrete so you will be able to secure the entire basement flooring. Next, go back to the holes and secure the subfloor basement flooring to the concrete using some good concrete screws and viola, you’ve just installed an envious and dry subfloor ready to tackle all your basement flooring needs. This subfloor will be able to handle anything from carpet flooring to hardwoods to pretty much anything you can throw at it.
This is one basement flooring preparation project that any do-it-yourself handy person can tackle. Stay tuned as Basement Flooring Guide will present another alternative method to subfloor your basement if this one didn’t suit your fancy.
- The Basics of Tile Basement Flooring
- Basement Flooring Preparation Alternative
- Engineered Basement Flooring For The Hardwood Look
{ 14 comments… read them below or add one }
Where can you purchase extruded polystyrene foam board?
Thanks
Jen
Hi Jen:
You should be able to pick this up at your local hardware/home improvement stores. You’ll typically find them called either “extruded” or XPS boards.
Would you recommend the use of a phywood over foam board subfloor for ceramic tile. I note that the statement that this subfloor will be able to handle anything from carpet flooring to hardwoods to pretty much anything you can throw at it stops short of mentioning tile.
I wouldn’t use this type of subfloor for ceramic tile per se. You would probably be better suited using a backer board type subfloor made with a cement substrate designed for use with ceramic tile in wet or dry areas. Common examples of these types of backer boards are Permabase, Wonderboard and Durock. Sorry about the misconception there, didn’t have tile on the mind when writing this one up.
what about depth of the drill bit into the concrete ? should I worry about hitting pipes ?
Hey Rex:
Most pipes are run under the slab and then through it being “stubbed” out and not actually in the concrete slab itself. Although there are instances where you may incur a pipe in your concrete, but it’s not likely that I know of. As far as depth of the drill bit into the concrete, depends on the screws you are using and the size of the polystyrene and plywood. Tapcon is a good concrete screw and here’s a site that has much more information on what you are asking http://www.concretefasteners.com/anchors-fasteners/tapcon-screw/faqs.aspx
When I place the subfloor do I have to cover the whole basement floor? I want to leave the area where the heater and water tank are unfinished. If this is okay, how then do you leave the subfloor edge where the unfinished portion meets the subfloor? It would seem that this will need protecting as not to erode under the plywood from walking back and forth. Thanks for any help, Brian.
Brian, I wouldn’t use this subfloor approach with what you are asking. You might look into something like Tyroc or similar instead.
I have a question, we are doing our basement with the foam backed Walmart Brand Laminate, do you still need any underpad or preparation for the foam backed laminate.
For a basement installation with a foam backed laminate, I would not suggest adding any additional underlayment or padding. You stand the chance of actually weakening the laminates and could cause them to bust at the seams. The backing already placed on them should be sufficient. However, it is suggested that you should still use at least some kind of poly moisture barrier underneath for added protection.
We have a walkout basement and the door is very low to the floor. A subfloor would be too high to clear the door and we can’t cut/plane the door down, because we would loose the seal. Any suggestions?
Hi Melissa, you could use what Jodi is suggesting above. If you have physical constraints that you just simply can’t get around then you have to go with what would work best. There are a lot of laminates on the market today that are rated for below grade installations that already have a small (3mm) foam backing attached. You could simply lay down a thin moisture barrier and install this type of flooring directly over it if you are crowded for space. Not being able to see your actual situation that’s probably the best I could suggest but be sure to check the manufacturers ratings and warranties before making a decision.
Some of the above posted questions are the same that I have….but don’t see any response answers???? Is there any chance you can answer them for me from “Melissa”, “Jodi”, “Brian”, & “Rex”. All of these relate to my basement as well which we are looking to finish the bare basement floor.
Hi Maureen, think I’ve got them all now. Hope they were what you were looking for and if you got any other questions, feel free to shout back.
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