Glue-Down Hardwood Floor Problems (And Their Solutions)

Hardwood flooring is still the most sought after and exceptional flooring options for residential homes around the country.

If you are installing a hardwood floor, you may think about the glue-down method. However, this can cause some problems down the road for you.

If you already have hardwood floors that were installed using the glue-down method, you may already be experiencing these issues.

In this article, though, we will cover the most common problems of glue-down hardwood floors, and present their solutions.

Read on to find out how to keep your hardwood floors looking great, no matter how they are installed.

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Benefits of Glue-Down Flooring

Hardwood flooring has a lot of benefits. Depending on the type of wood and how it is installed, the benefits can change. Let’s look at some of the best glue-down hardwood benefits here.

Increased Resale Value. Hardwood flooring is still the primary flooring that can increase the resale value of a home.
Less movement. All hardwood flooring will expand and contract, but glued-down boards are less likely to move excessively.
Durability and Strength. Hardwood flooring is highly durable and already strong, but glued-down hardwoods secured to the subfloor are even stronger.
Finishing and Staining. Unlike other flooring options hardwood flooring can be stained and finished to add aesthetics and beauty to the floor and your home.

Known Problems with Glue-Down Hardwood Flooring

All flooring will have problems at some point in its lifespan. Hardwood flooring is no different. However, the issues and problems that come up with glued-down hardwood flooring. Those problems all have various causes, as well, as solutions.

Plank Gaping

All hardwood will expand and contract with changes in temperature and humidity. However when the planks are installed with too much adhesive or in an excessively dry or humid area, abnormal gaping can occur.

Large gaps between the planks are unsightly, pose trip hazards and can make your once stunning floors look run down and aged.

Solution: To prevent abnormal gaps in hardwood floors you want to install using the minimal amount of glue and adhesive. You also want to ensure the boards have time to acclimate to your home’s natural humidity level for at least 24 hours before installation.

Flaking and Peeling

In some instances you will notice that the top layer of the hardwood is peeling or appears flaky. This is usually caused by improper care and maintenance. If you apply too much finish or polish it can start to dry out and peel off as it dries.

This can take weeks or months, but it discolors and chips off, giving the appearance of unattended floors. This can also be caused by subfloor moisture. As it evaporates it causes plank swelling and contracting on the bottom that makes the top layers break off the polish or wear layers.

Solution: Ensure that the annual finishing is done properly and that you (or by the contractor). Too much sanding, or too much polish can cause peeling and flaking. If the issue is subfloor moisture, this can be prevented by laying a moisture barrier down between the flooring and subfloor during install.

Cupping

Cupping is essentially a curl of the planks or floor boards. This is noticeable as the edges of the boards being higher than the center, forming a cup or dip in the board. Humidity and moisture are the primary root causes of this.

Flooding, wet mopping and steam mopping are the most common culprits. Of course moisture seeping from the subfloor (if it is concrete) can also be a cause. Almost always, though, it is due to wet or humidity from the top.

Solution: Once a board is cupped it will need to be replaced or severely repaired if possible. In most cases they will not lay back down on their own. Prevention is the best option here.

Never allow your hardwood floors to become flooded or have standing water from mopping stay in place for any length of time. Refrain from using steam mops on hardwood flooring, too.

Buckling

Buckling is a serious hazard and can come on suddenly. You will first notice it as a wiggling or loose board. Eventually one (or both) ends of the board will lift up and can cause a trip and fall hazard. It can also be loud when stepped on, creak or even break the board off.

There are a few main causes for this but most are due to a faulty install. Not using enough glue when you install the plank can cause it to lift away over time. If the glue being laid down isn’t evenly applied, the gaps and differences in height will also cause buckling.

Finally during the install if the subfloor isn’t properly cleaned, dirt and debris underneath will eat away at the adhesive when you walk over the flooring, eventually leading to the buckle.

Solution: During the initial install make sure that you take the additional time to properly clean the subfloor. You also want to use a trowel to apply the adhesive and ensure it is thin, level and abundant enough to hold the planks.

Clumping

Clumping is when there are high points around the floor. Right after installation it won’t be as noticeable and will show more and more over time. Essentially what happens is that the glue cures and hardens, holding the planks in place.

However, the adhesive was laid unevenly with little hills and valleys that the boards are placed on. Pressure from foot traffic, furniture and normal use will cause the boards to warp around these adhesive hills and the clumping becomes noticeable when all is settled.

Solution: During the adhesive application step of the install you need to ensure that the glue is troweled, even and flat. Remove any and all air bubbles and make sure the board, when laid flat, is in contact with the glue all the way around.

Crowning

Crowing is the opposite of cupping. This is when the board bows in the middle making it rise higher in the center than the edges. With crowning it can appear to happen fast, even though it takes some time.

While walking on a crowning board you won’t hear any sounds, the board isn’t loose and won’t move underfoot. It is also much less of a trip hazard since in most cases, the edges still align.

This is primarily caused by moisture in the subfloor or uneven application of the adhesive, similar to clumping. It is also caused by wood shrinkage, and high humidity levels.

Solution: During install you need to ensure that your subfloor is clean and dry and use a moisture barrier as needed. When laying the adhesive, make sure it is even, level and thin.

In the case of wood shrinkage, the only prevention is to ensure you purchase high-quality boards that are properly kiln dried during manufacturing.

Installation Tips for Glued-Down Flooring

Hardwood flooring can be a DIY project, but with such a high cost and need for near perfection, it is something, like carpeting, that is best left to the professionals. With engineered planks, and as a floating floor option, a DIY install is doable.

With solid hardwood planks as a permanent flooring (glue-down, nail-down) there is a lot more precision and expertise that is needed. This doesn’t mean it cannot be done, but unless you have the required tools, time and skills it may not work out well.

To prevent a lot of the issues mentioned above, it is always wise to hire the project out to the professionals. Not only will it get done faster, but you can also get a labor warranty that will cover any issues that come up.

There are two main downsides to professional installation. First, it can get expensive. Hardwood flooring installs can easily end up costing $2 to $5 per square foot. For larger areas this can easily reach the thousands of dollars range.

Secondly, finding a qualified and trustworthy contractor to perform the installation can be daunting. Between interviews, background checks, review and rating research, talking to pas customers and ensuring the contractor has the knowledge and licenses, there is a lot of work to do.

Or you can let us help! We have partnered with Networx to use their vast library of contractors and professionals. By utilizing out free tool, you can get reliable, vetted and fully checked pros right in your inbox.

Removing Glue-Down Hardwood

Once glue-down hardwood is difficult to remove. If you need to repair or replace a board it can be difficult to accomplish. You need to take your time on an already lengthy project, wear protective gear and have all the proper tools.

To get an idea of what is required, we will outline the basic process here.

Put on your protective equipment. At a minimum you need thick gloves for hand protection, knee pads and eye protection.
Use chalk to mark the removal area. Whether it is a single board or a small section.
Find the starting spot. Somewhere inside your removal area find a board edge that you can easily access. This is usually a corner or end part of a single board.
Use a chisel to loosen the edge and a sturdy floor scraper or larger putty knife to run along the edge and get under the plank. Pull up on the scraper handle steadily until the board starts to lift.
Continue sliding the scraper and chisel to loosen more and more of the board until you can get a hand under it safely. Pull up and continue to use the scraper to separate the glue from the board/subfloor.
Move to the next board and repeat the process until the entire marked removal area is clear.
Use a mop and warm, clean water and mop the removal area well. You want to get the remaining glue and adhesive wet and let it set so the water will loosen the glue.
Using your floor scraper to remove the glue and get to the subfloor.

Glue-Down or Nail-Down Hardwood? Which is Better?

For solid hardwood planks, installation will come down to gluing or nailing. Which is better? That is a judgment call based on your needs, budget and capabilities.

Both permanent install options offer you a secure mounting to your subfloor. Both also require level and solid subfloors, cleaned, prepped and repaired before the boards are laid. You also need to ensure you have the proper materials.

At a minimum you will need the tools for mixing the adhesive, spreading and applying the glue. For nailed options you need the nails, of course, but also wood filler to cover the nail holes and sandpaper for cleaning edges.

Various applications will have other needs, though, so make sure you know what your particular project calls for.

Gluing is more expensive as there are a lot more materials. Depending on the size of your project this can get quite costly. Nails are much cheaper, but take a lot longer to install. So essentially you trade cost for time.

Your subfloor type may determine which option you can use, though. While adhesive installs work on any subfloor type, nails will only work in plywood subfloors.

Frequently Asked Questions

In this section we will answer some of the most important questions about glue-down hardwood. As always, if you have further questions, feel free to use the comment section below.

Q. How long will the glue last on a hardwood floor?

In most cases your floor will last forever. The glue will get brittle and begin to crack, causing loose boards after about 20 years. Repair and re-gluing will be needed eventually, whether it is a spot treatment or the entire floor.

Q. Should you glue tongue and groove hardwood?

No. As a floating floor, tongue and groove installs should never be permanently adhered to the subfloor. These boards need to be able to expand and contract. If they are glued this will inhibit the natural movement of the wood causing it to bow, warp or pop up at the edges.

Q. Do I need glue if I am nailing down the hardwood?

When nailing it is advised to use adhesive glue sparingly to help assist the nails and prevent premature lifting. You won’t need as much glue since you are using the nails to secure the boars to the subfloor, but ends and edges will benefit from the added support. It can also prevent nail hole widening as the wood expands and contracts.

Q. What kind of glue should I use for my hardwood floor install?

This will depend on the type of subfloor you have. You will need a different adhesive for wood on wood install than you will for wood on concrete install. Make sure that your adhesive is designed for the material you are gluing. PL glue, for example, is ideal for wood subfloors, but won’t work well or last more than a couple of years (at most) on concrete.

Conclusion

Glue-down hardwood is one of many methods for hardwood flooring installation. However, it isn’t without it’s issues. Potential problems abound based on improper installation, moisture and humidity levels, too much adhesive and other factors.

Hopefully you have a better idea of the potential pitfalls when installing your wood floors with glue and can now avoid them.

When installed correctly, possibly even professionally, you will have a solid floor that will lay flat, look great and perform to expectations for years to come.