How To Build A Raised Floor On A Concrete Slab (Do This!)

Ossiana Tepfenhart
by Ossiana Tepfenhart
A concrete slab is not suitable for walking on, and just about any homeowner will want to put a raised floor over it. Generally, building a raised floor is left to contractors because of the complexity, but it is possible to build one on your own. Whether it be gathering materials and building the framework, let’s see how you can build a raised floor over a concrete slab.

If there’s one thing that we can all agree on, it’s that concrete slabs are not comfortable for your feet. They’re cold and icky. That’s why people often choose to build raised floors on them in order to boost the comfort levels of your home. At times, it can be the only way to add an extra bedroom to a basement. But, how can you do this, and is it even a good idea?

Building a raised floor is a highly complex procedure that is often better left to contractors. The overall process starts by setting up your floor for a new raised floor, putting together the framework, and then adding the rest of the flooring materials.

Building a raised floor is a smart move in most situations, but there’s more to picking your framework than meets the eye. Don’t worry, though. We’re here to help clear up common issues.

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Build Your Raised Floor: A Step By Step Guide

If you want to get your raised floor on, you are going to have to pay close attention to the process. We’re going to break it down by covering each major step in detail.


Like with any other major project, you need to make a point of prepping the area. Here’s what you are going to have to do:

  • Grab a Shop Vac, place the Shop Vac filter in, and give your entire basement a close cleaning. You cannot have dust, mold, or mildew nearby.
  • Start by figuring out how tall your raised floor will be. The most common raised heights are four and six inches. This will involve you putting everything on two by fours, or two by sixes.
  • Measure the length and width of your basement room. The length of your room will be the length of the sleeper, while the width, divided by 24 inches, will determine how many sleepers you need. You will also need an additional one for one of the walls.
  • Find out the area of your floor. This is going to be the area of the R9 fiberglass you will need to purchase in order to finish your flooring.

Lay Out The Framework

Once you have all the measurements, you’re ready to go to the wood shop and get the framework. Here’s how you can lay out your framework in a way that’ll make your raised floor last.

  • Lay a two by four (or two by six) at one long end of the wall. Mark off the wall at 24-inch intervals, width-wise. Then, place go to the opposite end of the room and repeat this process. Use a chalk rope to mark lines across the wall from mark to mark.
  • Grab the sleepers and align each of them along a chalk line. Make sure they are perfectly aligned. Mark 24-inch marks along each sleeper. Then, measure between the sleepers and cut some two by fours that measure that length.
  • Place the new joists at every measurement line. At every new joist, make sure that you use two 16D framing nails and a framing hammer to complete the installation. Repeat the process until all measurement lines have been adequately installed.
  • Do the same at each side of the floor’s width. You want to have a grid of joists and wood that extends from every edge of the floor inward once you’re done.

Time To Insulate!

Once you’ve laid out the framework, you are going to need to install the insulation and sheathing. Follow the instructions below to complete your raised floor:

  • Install R9 insulation, paper backing up, between the floor joists. If you need to add filler pieces, use a knife to do so.
  • Go to one end and corner of the wall, and install your plywood perpendicular to the joists. You want to align your plywood to the corresponding walls. To secure it in place, put 1 1/2-inch deck screws into the framework, six inches apart. You can use a power drill with a quality screw tip attachment for this.
  • Measure, cut, and install a filler. If you want to get more coverage, you can also just flesh up a sheet of plywood next to the first installed sheet, and install it next to it. Either way, you’re going to need to install all those plywood sheets. When installing, stagger your butt-joints so that you don’t end up with overlapping.
  • Measure and add filler pieces along the length of the wall. If your wall is totally covered, you won’t need to do this.
  • Secure your floor by adding deck screws at four-inch intervals along the outside framing of your floor. This will help keep your build solid. Ta da! You have a new floor you can tile up or carpet as you see fit.

Should You Call A Professional To Install A False Floor?

Honestly, this is usually a job that’s better left to the pros. It’s easy to make a mistake with a false floor and at times, it can even be against local building code to do it yourself. Considering how much the cost of installing hardwood flooring is (or really any type of flooring), it’s easy to get worried about growing costs.

The best way to think about it is that it’s an investment in your future flooring. Most of the time, it’s an investment that is worth it. Otherwise, you might have a slightly higher chance of seeing vinyl planking buckling if it’s installed on top. Before you try to do things yourself, find out what your building codes say in terms of legality. Otherwise, you may have a problem on your hands if you DIY it.

How Much Does Installing Raised Floor Cost?

This is not something that you want to do professionally unless you are totally sure that you want to spend a lot of money. This is not cheap. In fact, this is one of the most expensive things you can do in terms of flooring. Installing raised flooring will cost between $8 to $17, without even including a topping like vinyl or tile.

This means that an extremely small 10 x 10 room would cost a minimum of $800 before you even put laminate flooring on the area. As such, this is not an upgrade that you want to do without serious consideration of the cost. Most people will need several months’ worth of savings to do this.

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Related Questions

Does adding a raised floor to a basement improve home value?

Like with most other home improvement projects, there is a lot that can happen with a raised floor. While this is not considered to be one of the most in-demand options out there, studies show that having a false floor can improve your home’s value. This is particularly true if you want to add a new bedroom to the basement or something similar.If you want to make the most of your false floor, it’s best to have a full plan with what you will do on top of the floor. It’s worth noting that adding additional bedrooms is the best way to maximize your building’s value with a false floor.

Are there other ways to get a raised floor?

If you are looking for a higher raise than just four or six inches, you might want to consider buying a kit. Kits come with all the necessary parts to raise a floor several feet up in the air. They use pedestals, connectors, and extra sturdy panels to give your false floor the stability it needs to have.In many cases, these kits are deemed preferable to the old fashioned way of installing a series of two by fours. However, they are even more expensive than typical wood flooring.

Why would an office get raised access flooring?

Raised flooring is excellent if you want to have a way to run large batches of cables and cords through a floor without the risk of tripping over it. This is one of the best ways to get rid of cable clutter, improve the overall look of your office, and also prevent having employees trip. Areas that have large amounts of electrical use may benefit from a raised floor.

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Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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