Floating Subfloor

sub floor

Floating Subfloor for Basements

Problems with your basement? Is it nothing more than a cold, damp, unfinished storage room? Don’t feel like you are the only one as you probably have a lot more in common with other homeowners than you imagine when it pertains to your basement.

General rule of thumb is if it’s cold and damp it’s the concrete. Concrete is great and is the best standard when it comes to foundations, but when it comes to actual flooring unless you plan on spending the time and money finishing your concrete floor to make it sealed and shine, it has one inherent quality that’s not good.

It’s porous. If a flooring material is installed directly over concrete in a basement it will leave it feeling cold and damp. It doesn’t matter what you choose, whether it’s tile, laminates or even carpet, if you install it directly on concrete it will feel cold and have the possibility of getting damp.

If you really think about it that’s a ton of space going to waste in your home. If you have an average size basement, they can normally take up from a one-third to one-half of the entire space in your home. You should really be able to make the most of that space. A home office maybe? A guest suite for the in-laws?

Maybe that entertainment or home theater where you and the guys can escape and watch the Super Bowl or the family to retreat and see the latest flick.

Well, now you can and you can do it in comfort too with the ability to install an OSB floating basement subfloor. These subfloors were created with the weekend handyman in mind as you’ll soon see in a typical question/answer type format.

Question: What is a floating subfloor

Answer: Well, basically its a floor that goes over the concrete and under the finished flooring you are planning to install. They are very easy to assemble and you can knock it out during a day on the weekend.

They come in a standard two-foot by two-foot section and are put together using a tongue and groove panel setting (much like the tongue and groove you’ll find on engineered flooring or laminate flooring).

It’s said to be “floating” because it is not permanently connected to the concrete floor via nails, screws or glue. It just sits on top of the floor.

The subfloor though has one thing that really sets it apart. The OSB (or could be plywood) portion of the subfloor sits atop a waterproof, corrugated underlayment. This truly never lets the wood hit the concrete.

The corrugated portion of the underlayment creates an air gap just above the concrete and below the OSB flooring. When they are all placed together and “locked” in tight with the tongue and groove, it creates a generous thermal layer that acts like insulation for the floors and will warm them up.

Some products even state that it could raise the temperature of the flooring material installed on top of them as much as ten degrees.

Not only that, because they are corrugated and raised off the concrete, it actually acts like a moisture barrier because the wood doesn’t touch the concrete.

This keeps it dry from any of the natural water moisture that typically comes through concrete foundations, especially sub-level foundations.

This will also allow any water that accumulates here to easily evaporate or drain and highly reduce that stinky, musty smell and any mold that may grow.

Because of this kind of protection provided you could easily choose to install most flooring choices if you use this type of system in your basement.

A typical floating subfloor has a corrugated bottom and an OSB or plywood topside.

Question: How does a floating subfloor benefit my basement

Answer: One word, durability. This floating subfloor system is tough. As noted above and due to the nature of their construction, they are built to withstand a lot of the turmoil and mishaps that can regularly occur to a basement concrete floor.

Plus, you don’t have to worry about what you are going to have on top of it as it can withstand the weight of pool tables, refrigerators, workout systems so you can feel free to have the basement you really want.

Not only that they are an ideal foundation for basically any type of floating floor you might want to install as a finished product from laminate flooring, engineered flooring, cork flooring, vinyl flooring and even hardwood flooring and carpet.

You will want to check with the manufacturer of the specific brand that you choose but most warranty against any type of warping or splitting.

One of the better brands available on the market today is the DriCORE(tm) system. One of the big benefits touted by this system for all you do-it-yourselfers out there is that this DIY subfloor can be done in one days time and with the basic household tools that most handymen should already have so there’s no specialized equipment to buy.

Just plan your layout and start fitting the pieces of the subfloor system into place by tapping them together. Just remember to use a wood block or something as the cushion when tapping the subfloor pieces together.

Question: How do you install a floating subfloor?

Answer: Well, one of the first things that you don’t want to do is simply go out and get a subfloor system and start to immediately install it especially if this is for a basement application.

Go get the material and store it in the room where it’s going to be installed for at least twenty four hours so it can get acclimated to where it’s going to be. I know, sounds strange, but this will let the moisture content of the material adjust to the room it’s going to be in so you won’t have problems the day after you install the subfloor.

While the subfloor is climatizing, you can take the opportunity to shore up the foundation in any problem areas that you might have.

If you have a seepage problem in your basement definitely fix it now. Do the standard moisture checks using the plastic sheeting and tape and fix it all up right.

If moisture collects or beads up your best bet would be to seal it with a concrete sealer prior to installing the subfloor.

The last step in prepping the slab for subfloor installation is to simply sweep or vacuum up all the dust and debris that may be present to ensure you are working with a semi-smooth surface.

Don’t worry if the basement floor is not completely level as the subfloor system should come with shims you can use for leveling during install. Any more than a quarter inch though and you could have a problem that would need correcting via some kind of leveling compound.

The shims will correct an unlevel basement floor within that range. As with any type of floating floor installation you will need to account for a quarter inch gap around all walls and columns in the room for expansion.

You can accomplish this by either snapping a chalk line or even better using some quarter inch strapping pieces butted up against the walls and wherever else needed. This way is probably the easiest method to use to acquire that needed expansion gap.

After that, start off placing the panel down in your starting point (most likely should be a corner of the room), align the next one and tap it into place using a block of wood and a hammer.

Be sure to use the wood block to cover the panel where you will be hammering as it will force even pressure and not damage the panels when setting the tongue and groove pieces.

You’ll want to make sure that they fit well and are not loose so the don’t separate later. Take your time and set the first rows good as that sets the mold for the rest of your subfloor installation.

As you work your way down the rows you are going to want to stagger the panels so the middle seams don’t line up. Every other row should align in the middle with the previous rows panels. This will lock the panels in place.

Question: What’s the best way to plan a floating subfloor layout?

Answer: First thing you need to keep in mind here is that although the walls may look square, all walls are not created equal. Check to see that the corner you plan to start with is square.

You can use a common framing square to see if it’s true or not. If it’ not then just keep in mind that you’ll be trimming the edge closest to the wall for the first row of subfloor. This will keep the following rows square in comparison.

Some things to keep in mind while you are planning, rows should be staggered and no edge should be less than six inches.

Knowing this because you are working with a square subfloor system, its no different than if you were doing a tiling job. Get the measurements of the room and divide it by the width of the panels.

Sometimes it’s best as I’m a typical strong back/weak mind type person to write it all down and actually sketch out the layout somewhere. Once that’s all done and finalized take a chalk line and snap the grids for your subfloor installation.

Question: What sort of tools do I need to install a floating subfloor?

  • leveling kit(if needed)
  • square
  • pry bar
  • hammer or rubber mallet
  • circular saw
  • jig saw or rotozip
  • chalk line
  • tape measure
  • pencil for marking
  • dust mask and safety googles for cutting

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