Before installation of your laminate floor, proper subfloor preparation is an important step to ensuring long-lasting floors.
What is a Subfloor?
A subfloor is the structural layer beneath the visible flooring surface.
It provides a strong foundation upon which your laminate flooring is installed. It plays the role of providing strength, stability, and durability to your laminate floor.
Bad subfloor preparation often results to laminate flooring problems including squeaks, uneven flooring, wobbling and damage to the laminate planks including peeling.
This comprehensive guide provides you with the knowledge you need to ensure a fool-proof subfloor preparation.
The guide covers everything you will need to achieve an optimal subfloor condition which includes:
- assessing the subfloor’s current state
- performing necessary repairs
- levelling uneven areas
- installing moisture barriers
- preparing surface for proper adhesion.
Do you need subfloor for laminate flooring?
Yes, you need subfloor for laminate floor because it is a floating type of flooring which means that it is designed to be installed over an already existing substrate.
The laminate must be evenly distributed over an existing subfloor such as concrete or wood. The subfloor provides a stable base upon which the laminate planks are laid.
You should also note that the type of subfloor you choose will also determine whether you can immediately walk over your laminate flooring after installation.
Common types of subfloors for laminate floors
1.Plywood Subfloor:
Plywood is a widely used and versatile subfloor material for laminate flooring. It offers a stable and durable surface.
For optimal support, ensure that the plywood subfloor has a thickness of at least 3/4 inch (19mm).
For example, if you are using a plywood subfloor in a living room, you can install 12mm laminate flooring over a 3/4-inch plywood subfloor.
2.Concrete Subfloor:
Concrete subfloors are commonly found in basements or ground-level floors.
They can provide a solid and sturdy foundation for laminate flooring.
However, proper moisture testing and sealing are crucial before installation.
You may need to apply a moisture barrier and use an appropriate adhesive to install 8mm laminate flooring over a concrete subfloor in a basement.
Related:
3.Oriented Strand Board (OSB):
OSB is an engineered wood panel that is often chosen as a subfloor for laminate flooring.
It is made by compressing layers of wood strands with adhesive, resulting in a strong and reliable surface.
Similar to plywood, the recommended thickness for an OSB subfloor is 3/4 inch (19mm).
4.Particleboard Subfloor:
Particleboard, a composite material made from wood particles bonded together with resin, can be used as a subfloor for laminate flooring.
However, it is generally not as durable or moisture-resistant as plywood or OSB.
If using particleboard, ensure it has a thickness of at least 3/4 inch (19mm) to provide sufficient support.
5.Vinyl Subfloor:
If you have ever wondered whether you can install laminate over vinyl flooring, the answer is Yes.
Vinyl subfloors consist of vinyl sheets or tiles that are glued or snapped together. They offer a smooth and moisture-resistant surface for laminate flooring installation.
Prior to installation, it’s important to ensure that the vinyl subfloor is in good condition and properly prepared.
6.Existing Hardwood Subfloor:
If you have a pre-existing hardwood subfloor in good condition, it can serve as a suitable surface for laminate flooring.
Ensure the hardwood subfloor is flat, clean, and structurally sound. If necessary, sanding and leveling may be required to provide an optimal surface for installation.
7.Tile/Stone Sub-Floor
In some cases, laminate flooring can be installed directly over an existing tile or stone subfloor. However, certain conditions must be met, such as the subfloor being clean, level, and in good condition.
It may be necessary to use an underlayment or adhesive suitable for laminate flooring installation over tile or stone. The underlayment improves the leveling of the tile floor and makes it even.
8.Gypcrete Subfloor:
Gypcrete, also known as gypsum concrete, is a self-leveling compound that consists of gypsum and other additives.
It is commonly used in multi-story buildings or when soundproofing and fire resistance are desired. Gypcrete provides a smooth and level surface for laminate flooring installation.
Subfloor Preparation: Step-By-Step.
Step 1: Assessing Sub-Floor Condition
A. Inspecting the Moisture Levels
Checking for moisture-related problems is important in subfloor preparation because moisture issues could result to problems such as buckling or warping of laminate planks, peeling, mold growth, and overall compromise of your laminate flooring structural integrity.
You check for moisture so that you can prevent and protect your floor.
First, you are able to prevent moisture from seeping to the laminate planks by identifying any rising dampness in your sub-floor.
You should also check for plumbing leaks in the subfloor, as well as any condensation. If not identified before installation, the moisture results to mildew and mold growth.
Besides, the moisture can also affect the adhesive used in installing laminate flooring compromising its ability to bond the planks securely onto the subfloor.
This results in loose and squeaky floors, gaps between the planks and premature wear and tear.
Recommended methods for testing subfloor moisture levels.
Two of the most common methods you can use for testing subfloor moisture content are the calcium chloride test and the moisture meter test.
1.Calcium Chloride Test:
This test involves placing a small dish of calcium chloride on the subfloor and covering it with a plastic dome.
Over a specific period, typically 24 to 72 hours, the calcium chloride absorbs moisture from the subfloor. After the designated time, the dish is weighed to measure the moisture absorption rate.
This test provides a quantitative measurement of the moisture emission rate in pounds per 1,000 square feet per 24 hours (lbs/1,000 sq ft/24 hrs), indicating the level of moisture present in the subfloor.
Read our calcium chloride step-by-step guide.
2.Moisture Meter Test:
Moisture meters are handheld devices that measure the moisture content of materials. They use either pin or pinless sensors to determine the moisture levels within the subfloor.
Pin-type moisture meters penetrate the subfloor surface using small pins, providing moisture readings at various depths.
Pinless meters, on the other hand, use sensors placed on the subfloor surface to detect moisture without damaging it. Moisture meter readings are usually displayed as a percentage of moisture content.
These devices help in assessment of the moisture condition of the subfloor accurately.
It is important to note that moisture levels may vary depending on the type of subfloor material.
Laminate flooring manufacturers often provide specific guidelines regarding acceptable moisture levels for installation.
Ensure that the subfloor moisture content falls within the recommended range before proceeding with the laminate flooring installation.
Read our moisture meter testing guide for more details.
B. Addressing Structural Integrity:
Ensuring the structural integrity of the subfloor is important for a successful laminate flooring installation.
Identifying and addressing subfloor stability issues, as well as repairing or reinforcing weak or damaged areas, is essential to create a solid and level foundation.
Identifying and Addressing Subfloor Stability Issues
During the subfloor preparation process, it is important that you assess the stability of the existing subfloor.
Walk across the floor, paying close attention to any areas that feel uneven or produce squeaking sounds. These signs may indicate underlying structural problems that need to be addressed.
Subfloor instability can occur due to a variety of reasons including:
- inadequate support,
- water damage
- joist movement,
- weakened subfloor materials.
Identifying the root cause of the instability is required to determine the appropriate course of action.
If the subfloor instability is related to inadequate support or joist movement, additional support may be required.
This can be achieved by adding bridging or blocking between the joists to enhance their stability. Reinforcing the subfloor with additional screws or nails can also help to secure loose or squeaky areas.
Repairing or Reinforcing Weak or Damaged Areas
You should also repair and reinforce the weak or damaged areas in the subfloor to ensure a solid foundation for the laminate flooring.
These areas can compromise the stability and durability of the floor, leading to issues such as flexing, unevenness, or premature wear.
To repair weak or damaged areas, follow the following steps:
- Start by removing any loose or deteriorated subfloor material.
- Replace the damaged sections with new subflooring material that matches the existing thickness.
- Use construction adhesive and screws to secure the new subfloor to the underlying joists, ensuring a secure and stable attachment.
- If the weak or damaged areas are limited to small spots, additional reinforcement may be necessary.
- This can be achieved by adding blocking or sistering joists to strengthen the affected areas.
- Sistering involves attaching new joists to the existing ones, providing added support and stability.
It is important to note that subfloor repairs and reinforcements should be carried out according to local building codes and industry best practices.
Consulting with a professional contractor or structural engineer can provide valuable guidance in determining the appropriate repair methods for your specific subfloor condition.
By addressing subfloor stability issues and repairing or reinforcing weak or damaged areas, you ensure a stable and solid foundation for your laminate flooring.
This not only enhances the overall performance and longevity of the flooring but also provides a level surface for the installation process.
Step 2.Subfloor Preparation
Clearing the Subfloor:
Before proceeding with the installation of laminate flooring, you need to clear the subfloor of any existing flooring materials and debris.
This step ensures a clean and smooth surface for the subsequent subfloor preparation. You can follow these steps in removing and disposing of debris:
- Remove any old flooring materials present on the subfloor. This may include carpet, vinyl, hardwood, or tile.
- Use appropriate tools such as a pry bar, scraper, or floor stripper to carefully lift and detach the flooring materials.
- Dispose of them responsibly or consider recycling options if available.
- Once the flooring materials have been removed, clear the subfloor of any debris, such as loose nails, staples, or adhesive remnants.
- Sweep the subfloor thoroughly, and use a vacuum or broom to ensure all dust and small particles are removed. Pay attention to corners, edges, and hard-to-reach areas.
Cleaning the Subfloor Surface
After clearing the subfloor, the next step is to clean the surface thoroughly.
Proper cleaning ensures optimal adhesion of the laminate flooring and helps remove any contaminants that could potentially affect the installation process.
Follow these next steps:
- Start by dusting and Sweeping: Use a broom or vacuum cleaner to remove any remaining dust, dirt, or loose particles from the subfloor surface. Pay attention to the corners and edges where debris tends to accumulate.
- Washing and Drying: Depending on the subfloor material and manufacturer’s recommendations, you may need to wash the subfloor surface using a suitable cleaner. Follow the instructions provided by the cleaner manufacturer and use a mop or sponge to apply the cleaner evenly.
- After cleaning, ensure that the subfloor is thoroughly dried before proceeding to the next steps. Moisture left on the subfloor can negatively impact the adhesion and performance of the laminate flooring.
- Removing Adhesive Residues: If there are adhesive residues from the previous flooring installation, they need to be removed to ensure a smooth surface for the laminate flooring.
- Use a recommended adhesive remover or scraping tool to eliminate any stubborn adhesive remnants.
- Follow the manufacturer’s instructions carefully and ensure proper ventilation during this process.
Levelling the Subfloor
Before proceeding with the installation of laminate flooring, it is important that you identify and address any uneven spots or height variations on the subfloor.
Uneven subfloors can lead to issues such as unstable flooring, visible gaps, or premature wear.
To determine the presence of unevenness, visually inspect the subfloor for any noticeable slopes, dips, or raised areas.
Walk across the floor, paying attention to any areas that feel uneven or produce a bouncing or sagging sensation.
To obtain a more accurate assessment, use a level tool, such as a long spirit level or a laser level. Place the level tool on different areas of the subfloor, ensuring it spans a significant portion.
Check for any discrepancies in the level bubble or laser line, which indicate unevenness
If uneven spots or height variations are detected, a leveling compound can be used to create a flat and even surface for the laminate flooring.
A leveling compound is a self-leveling material that can fill in low areas and smooth out high areas, providing a consistent subfloor surface.
To use a leveling compound, follow these general steps:
a. Prepare the subfloor: Clean the subfloor thoroughly, removing any debris, dust, or adhesive residues. Ensure the surface is dry and free from moisture.
b. Prime the subfloor: Apply a suitable primer to the subfloor surface, following the manufacturer’s instructions. Priming helps improve the adhesion of the leveling compound.
c. Mix the leveling compound: Prepare the leveling compound according to the manufacturer’s instructions. Mix it thoroughly to achieve a smooth and consistent consistency.
d. Apply the leveling compound: Pour the leveling compound onto the subfloor, starting from the lowest areas and working towards the higher areas.
Use a trowel or squeegee to spread and smooth the compound evenly. Follow the manufacturer’s guidelines regarding the thickness and drying time of the leveling compound.
e. Allow curing and drying: After applying the leveling compound, allow it to cure and dry completely as per the manufacturer’s instructions.
This usually takes several hours or overnight. Avoid walking or placing heavy objects on the leveling compound until it has fully hardened.
- Sanding and Smoothing
In some cases, sanding may be necessary to achieve a perfectly level subfloor surface.
After the leveling compound has dried, use a floor sander or a sanding block to smooth out any rough areas or high spots.
Be careful not to sand too aggressively, as this can create unevenness or damage the subfloor.
By identifying unevenness and using a leveling compound or sanding technique, you can achieve a flat and even subfloor surface.
This provides a stable foundation for the laminate flooring, ensuring a visually appealing and long-lasting installation.
Moisture Barrier Installation.
Installing a moisture barrier is an important step in subfloor preparation before laminate flooring installation.
A moisture barrier acts as a protective layer, preventing moisture from seeping into the subfloor and affecting the performance of the flooring.
It helps to maintain a dry and stable environment, reducing the risk of damage, mold growth, or warping.
There are different types of moisture barriers available, including plastic sheeting, vapor barriers, and moisture-resistant underlayment.
The specific type of moisture barrier recommended may vary depending on factors such as the subfloor material, location, and local building codes.
It is important to consult the manufacturer’s instructions and guidelines to determine the most suitable moisture barrier for your specific installation.
The installation procedure for a moisture barrier generally involves the following steps:
- Ensure that the subfloor surface is clean, dry, and free from debris or imperfections.
- Remove any adhesive residues or protruding nails that may interfere with the installation of the moisture barrier.
- Measure the dimensions of the subfloor area and cut the moisture barrier accordingly. Allow for some overlap at the edges and seams to ensure complete coverage.
- Unroll or unfold the moisture barrier across the subfloor, starting from one end of the room. Ensure the barrier is positioned correctly, covering the entire subfloor area.
- If multiple rolls or sheets are required, overlap them by a few inches and secure them together using adhesive or tape recommended by the manufacturer.
- Seal the edges and seams: Pay special attention to sealing the edges and seams of the moisture barrier to prevent moisture from penetrating.
- Use a suitable adhesive or tape recommended by the manufacturer to create a watertight seal.
- Trim any excess moisture barrier using a utility knife, ensuring a neat and uniform appearance.
Step 3. Acclimating Laminate Flooring
Allowing laminate flooring to acclimate to the environment is an important step that helps ensure its stability and longevity after installation.
Acclimation refers to the process of allowing the flooring material to adjust to the temperature and humidity conditions of the installation area.
The significance of acclimation lies in the fact that laminate flooring is made of multiple layers, including a top wear layer, a decorative layer, and a stabilizing core.
These layers can expand or contract based on the surrounding environmental conditions, such as temperature and humidity.
Acclimating the laminate flooring minimizes the risk of excessive expansion or contraction after installation, reducing the chances of gaps, buckling, or warping.
See our comprehensive guide on laminate flooring acclimatization to understand the specific steps you need to follow.
Recap:
Proper subfloor preparation is crucial for a successful installation of laminate flooring.
By understanding the significance of subfloor preparation and following the necessary steps, you can ensure a stable, level, and moisture-resistant foundation for your laminate flooring, resulting in a beautiful and long-lasting floor.
FAQs (Frequently Asked Questions):
Can I install laminate flooring over an existing subfloor?
In most cases, yes. Laminate flooring can be installed over various subfloor materials such as plywood, OSB, concrete, or existing vinyl or linoleum flooring.
However, it is essential to ensure that the existing subfloor is in good condition, free from moisture issues, and level.
Proper cleaning, leveling, and addressing any subfloor imperfections are necessary before installation.
Do I need to use a moisture barrier under laminate flooring?
Using a moisture barrier is highly recommended, especially in areas prone to moisture, such as basements or rooms on or below ground level.
A moisture barrier helps protect the laminate flooring from moisture seeping through the subfloor, which can cause damage, warping, or mold growth.
Follow the manufacturer’s instructions to select the appropriate moisture barrier for your specific installation.
How long should I let the laminate flooring acclimate before installation?
The recommended acclimation duration can vary depending on the manufacturer and product. In general, laminate flooring should acclimate for a minimum of 48 to 72 hours.
However, refer to the manufacturer’s instructions for the specific acclimation duration and follow their guidelines for the best results.
Can I install laminate flooring directly over a concrete subfloor?
Yes, laminate flooring can be installed over a concrete subfloor. However, it is crucial to check for moisture issues and ensure the subfloor is level.
Installing a moisture barrier is highly recommended to prevent moisture-related problems.
Additionally, using an underlayment designed for concrete subfloors helps provide insulation and a cushioned surface.
References
