Hardwood Floors Over Concrete

Hardwood Floors Over Concrete: What You Must Know

In Remodeling by Giovanni ValleLeave a Comment

Nothing says comfy and welcoming like a hardwood floor in your house. Hardwood floors have such a rustic and pleasing texture with a wide variety of colors, shapes, and materials to match perfectly with your home. However, if you are thinking of placing a hardwood floor on a concrete base, the remainder of this article will review what you need to know.

A hardwood floor requires a clean, flattened, concrete slab. There should also be a vapor retarder such as asphalt felt with asphalt mastic or polyethylene sheathing. Then, a subfloor – be it a plywood-on-slab or sleeper – needs to go over the concrete and vapor retardant. Finally, the hardwood floor planks can be placed.

Placing a hardwood floor over concrete is not necessarily complicated. In fact, the process is fairly simple. However, if you wish to get the best quality hardwood floor and make it last for as long as possible, there are some things you should know more in detail.

Advantages of Having a Hardwood Floor Over Concrete

Hardwood floors are arguably the most stylish and welcoming floors in the market. They are warm, soft, and can even last for centuries, so they are definitely good for styling your house. They are also incredibly easy to set up and replace since they are installed in sections.

Having concrete under your hardwood floor provides both the advantages of having a solid concrete foundation for your house and the aesthetic and comfort of a wooden floor. The concrete will also work as great protection for your wooden floor since it will not be in contact with the elements.

Despite being called “hardwood floors,” hardwood floors are actually incredibly soft. They don’t pose much resistance to falling objects since wood and plastic, which hardwood floors are made of, are very soft materials. This can actually make your house safer than having only a concrete floor.

Disadvantages of Having a Hardwood Floor Over Concrete

There are a few disadvantages and responsibilities that come with having a hardwood floor over a concrete base. Since wood and plastic are rather malleable and sensitive materials, they do not pose as much resistance as a concrete floor.

Owning a hardwood floor requires a lot of maintenance and caution. Elements such as moisture and dust are pretty easy to overlook and should be taken care of almost immediately to avoid damage. Additionally, wet shoes and animal paws are a sneaky way for moisture to get on your floor. Furniture legs can also pose a hazard for your floor’s integrity.

Compared to a concrete or tile floor, hardwood floors are actually very soft, and flammable. You should be very careful when handling fire inside your house since wood and plastic can easily catch fire.

The process of setting a hardwood floor over your concrete base is a lot more lengthy than simply putting tiles over the concrete slab. It also requires a lot more materials, driving up the cost. Also, concrete tiles do not require nearly as much maintenance or as many precautions as a hardwood floor.

Now that you know the advantages and disadvantages of owning a hardwood floor, let’s move on to what is needed to install one.

How to Install Hardwood Floors Over Concrete

In order to correctly place a hardwood over a concrete slab, there are a couple of requirements and materials needed for the preparation, installation, and maintenance of your floor.


If you still haven’t laid your concrete base, then the first and most important material is concrete. The reinforced concrete base will essentially separate your floor from the natural dirt below your house and protect your hardwood floor against the elements. It will also be a reference point for the entire project.

  • The next important material is the vapor retarder. The vapor retarder serves as a barrier to protect your hardwood floor against moisture. It goes above the concrete base and beneath the subfloor. For a vapor retarder, you have two options, which are asphalt felt with asphalt mastic or polyethylene sheathing.
  • Next is the subfloor. The subfloor’s purpose is to allow you to fasten your hardwood floor to the setup while keeping it as far from the moisture as possible. For subfloors, you also have two options, which are plywood-on-slab and sleepers. Sleepers are a set of rows of wood that are fastened to the concrete with screws.
  • Lastly is your hardwood floor of choice. Hardwood floors come in strips, planks, and tiles, but since the installation process for the three is similar, we will only refer to them as planks. These are nailed to the subfloor with hidden nails and/or staples that go on a thinner wooden platform that goes on the long side of the plank.

Hardwood planks come in all shapes and colors, meaning that you have a wide variety of colors to choose from to match with your house. You can cut the planks as needed to fit them in each individual room.

The materials can range widely when it comes to cost and quality, so make sure that you get them from the right provider.

Now that we’ve outlined the necessary materials for a sturdy and durable hardwood floor on concrete, it’s time to outline the preparation process.


The preparation process is incredibly important for the entire project. Installing a hardwood floor might not be exactly complicated, but it sure is a heavy workload. Don’t be ashamed of asking for help or even hiring a handyman to help you set up your floor. After all, they might have experience in the field that could definitely come in handy.

  • Assuming that you still need to lay your concrete base, the concrete needs to be laid on a well-drained soil base. Rebar needs to be placed on the soil in order to strengthen the concrete base. A wet mix will make things a little easier, but a drier mix, although more difficult to mold, will offer the best results.
  • Next is the vapor retarder. The asphalt mastic is a mix and needs to be heated in order to be placed over the asphalt felt. It is important for it to be heated right before being poured. Alternatively, you can use cuts of cold asphalt mastic instead, which might turn out to be simpler to prepare and use.
  • When it comes to the subfloor, measurements must be made in order to make sure that the plywood will completely cover the concrete base and vapor retarder; any cuts that are necessary must be made. The same thing goes for the assortments of sleepers. These cuts can be made as they are placed.
  • Lastly, there are the hardwood planks. The hardwood planks, just like the subfloor, require exact measurements of the room’s floor in order to cover the entire surface and not let the subfloor or vapor retardant be exposed. Any necessary cuts must be made and can be made as the planks are being placed.


Now that you have all your materials and the work area is well laid out, planned, and prepared, it’s time to install all the components.

  • The first step is to place rebar on the soil bed to strengthen the concrete slab. Then the concrete mix should be poured and spread across the entire area. The concrete should be well flattened and left to dry. This process can be as long as 60 days since you do not want any moisture in your concrete slab.
  • Then, the vapor retardant should be placed. The process for placing the asphalt felt with mastic depends on which subfloor you will use. If it is the plywood-on-slab, then there must be two layers, each consisting of asphalt felt over cold mastic under the subfloor. If you will be using the polyethylene, then it is to be laid on the concrete slab before laying the plywood on top.
  • When it comes to the sleepers, asphalt primer should be placed, and then the sleepers should be embedded on hot or cold asphalt mastic. An additional polyethylene layer must be placed on top of the sleepers. Regarding the subfloors, the process is fairly simple for the plywood-on-slab, since all that is needed is to lay the boards on the vapor retardant. However, when it comes to sleepers, they must be laid in rows going in the same direction as your hardwood planks.
  • And finally, there are the hardwood planks. The hardwood planks should be nailed to your subfloor through the use of invisible nails that go on the small space sticking off the side of the plank. They should be laid in the same direction as your sleeper’s subfloor.

The installation process is delicate, and in order to achieve the best results, it has to be done properly. It’s important to be well aware of the hazards to look out for which could seriously hinder the project.

Things to Look Out for When Installing Hardwood

There are many elements and hazards that can be very easy to overlook and could ruin your entire hardwood floor. Therefore, it’s important to know them and how to overcome them. These will be outlined in the same order as their related installation step:

First, there is the ground level, which can be above-grade, on-grade, or below-grade. As the names imply, these refer to above, on, and below ground level, respectively. When it comes to on – and above -grade, the installation process can be carried on as usual.

However, when the floor is below-grade, moisture becomes a problem. In order to deal with the moisture below ground level, engineered wood floors are used instead of the normal hardwood planks. Otherwise, the installation process is basically the same.

Another way moisture can threaten your beautiful hardwood floor installation is through wet concrete. Concrete is mixed with water in order to be spread into a slab. It can take up to 60 days for the slab to dry fully. However, the process can be sped up through added heat and ventilation.*

Regarding the concrete slab, it’s imperative that it is completely flattened and that there is no debris, stains, oil, or dust on the slab before the vapor retarder or the subfloor are applied.

These are great methods of overcoming the elements and hazards that could threaten your hardwood floor setup. However, your hardwood floor is not entirely safe after being installed. You will have to take care of it, too.

*Note: Speaking of heat and ventilation, hardwood floors are quite flammable, meaning that you must be very careful when using fire around the house. To avoid this, make sure not to leave any cloth or rags close to power outlets that could short circuit. Be especially careful of not leaving the stove or the oven on while not in the house. Also, note that different hardwood floors have different safety ratings.


The goal of any hardwood floor is to stay clean and shiny. However, elements such as dust and moisture can permanently stain or even damage your hardwood floor’s impeccable image. Fortunately, there are ways of avoiding this damage.

  • Moisture is possibly your hardwood floor’s worst enemy. From the process of installation to its everyday life after being installed, moisture could swell and distort your hardwood planks slowly over time. Spills, in particular, are very common and should be cleaned using a dry or slightly damp cloth.
  • Another important thing to know in order to avoid moisture is to avoid steam cleaning and wet mops since you would be applying constant moisture to the planks. Instead, you should constantly sweep and vacuum your hardwood floor. The purpose of constantly vacuuming and cleaning your hardwood floor is to get rid of dust. When stepped on, dust can severely scrape your floor, damaging its clean and beautiful image, which is why it is important to get rid of it as soon as it enters the house. Also, there are sprays specifically made for wood floor cleaning in the market that you can use.
  • Another way in which your floor could get severely damaged through furniture scraping. Furniture is pretty heavy and tends to have sharp edges on its legs, meaning that moving it around the floor is like cutting your floor with a knife. Floor protectors that go under your furniture’s legs are a good way of dealing with this.
  • In order to protect your hardwood floor’s clean and shiny appearance, it’s important to re-coat it with a new coat of wood floor finish every three to five years. Also, never wax a polyurethane floor, since it will simply dull your floor.

Now that you know how to install and maintain your hardwood floor, you can enjoy its long-lasting beauty and cleanliness, too!

In Summary

Hardwood floors on concrete are quite simple to install and don’t require many materials. However, there are many dangers and hazards that you need to look out for during and after installation, such as moisture and dust.

A hardwood floor on concrete consists of a concrete slab, a vapor retarder on top to fight off moisture, a subfloor to separate the concrete and vapor retarder from the main hardwood floor, and, lastly, a hardwood floor of your choice.

Your choices for a vapor retarder are a polyethylene sheet or and asphalt felt with asphalt mastic. Likewise, you have two choices for subfloors, which are plywood-on-slab and sleepers. Sleepers tend to be more complicated to set up than a plywood-on-slab.

In order to take care of your floor after installation, you need to make sure to dry any spills and avoid wet cleaning, such as wet mopping. Instead, you should constantly sweep and vacuum your floor in order to get rid of any dust that could scrape your floor when stepped on. Also, you should apply floor protectors under your furniture’s legs to avoid scraping.

Hardwood floors have many advantages and disadvantages compared to a concrete tile floor. A hardwood floor is softer, warmer, and (although this is up to personal preference) somewhat more welcoming than a hard concrete floor.

However, hardwood floors tend to get damaged a lot more easily than concrete tile floors. They require a lot more maintenance and precautions. They are also more flammable, which, depending on your situation, could be a hazard. Also, they are more difficult to set up and require more materials, which means that they tend to be more expensive.

With all that being said, hardwood floors can be a challenge to install and maintain, but one that is definitely worth it.


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