Understanding Subfloor and Underlayment for SPC Flooring Installation

Flooring installation is a crucial aspect of home renovation, especially when installing SPC (Stone Plastic Composite) flooring. Two key components that significantly impact the longevity and durability of SPC flooring are the subfloor and underlayment. Understanding their roles and how to prepare them properly ensures a flawless flooring outcome.

What is a Subfloor?

The subfloor is the structural base that supports the finished flooring. It serves as the foundation for the entire flooring system. Subfloors are typically made of plywood, OSB (oriented strand board), or concrete. A well-prepared subfloor is critical for the longevity of SPC flooring.

Types of Subfloors

1. Plywood Subfloor: A common choice in residential homes, providing a sturdy foundation.

2. Concrete Subfloor: Often found in basements and high-rise buildings, requiring moisture management.

3. OSB Subfloor: An alternative to plywood, though not as water-resistant.

What is Underlayment?

Underlayment is a thin layer placed between the subfloor and SPC flooring. It provides cushioning, sound absorption, and moisture resistance. Choosing the right underlayment enhances the performance and lifespan of SPC flooring.

Types of Underlayment for SPC Flooring

1. Foam Underlayment: Offers comfort and noise reduction.

2. Cork Underlayment: Eco-friendly and excellent for soundproofing.

3. Rubber Underlayment: Provides superior durability and moisture resistance.

4. SPC-Specific Underlayment: Some SPC flooring comes with an attached underlayment for convenience.

Why Subfloor and Underlayment Matter in SPC Flooring Installation

• Moisture Protection: Prevents damage from moisture seepage.

• Noise Reduction: Reduces sound transmission, especially in multi-story buildings.

• Comfort & Insulation: Adds a cushioning effect, making floors more comfortable underfoot.

• Smooth Installation: A well-prepared subfloor and underlayment ensure a level surface, preventing flooring issues like buckling or warping.

Steps to Prepare the Subfloor and Install Underlayment

Step 1: Inspect and Clean the Subfloor

• Remove debris, dirt, and old adhesives.

• Ensure the subfloor is dry and free from moisture damage.

Step 2: Repair Any Damage

• Fill in cracks and holes with leveling compound.

• Sand down uneven surfaces to ensure smooth installation.

Step 3: Install a Moisture Barrier (If Needed)

• Concrete subfloors require a vapor barrier to prevent moisture penetration.

• Use polyethylene sheets or SPC flooring with built-in moisture protection.

Step 4: Lay the Underlayment

• Roll out the underlayment, ensuring it covers the entire floor.

• Tape seams together but avoid overlapping layers.

• Follow manufacturer guidelines for proper underlayment selection.

Step 5: Begin SPC Flooring Installation

• Start laying the SPC planks over the underlayment.

• Click-lock systems make installation seamless and easy.

• Leave an expansion gap around the edges to accommodate natural expansion.

FAQs

1. Is underlayment necessary for SPC flooring?

Yes, underlayment improves comfort, sound absorption, and moisture protection.

2. Can I install SPC flooring over an uneven subfloor?

No, uneven subfloors can cause SPC planks to shift or warp over time.

3. How do I know if my subfloor needs repair?

If there are cracks, soft spots, or moisture damage, the subfloor requires repair before SPC installation.

4. Can I use carpet underlayment for SPC flooring?

No, carpet underlayment is too thick and soft, leading to instability in SPC flooring.

Conclusion

A properly prepared subfloor and the right underlayment are essential for a successful SPC flooring installation. By ensuring moisture protection, leveling, and noise reduction, you can achieve a durable and aesthetically pleasing floor. For professional buyers and contractors, investing in quality underlayment and preparing the subfloor correctly ensures long-lasting flooring performance.

Basic knowledge: Subfloor vs. Underlayment

Subfloor vs. Underlayment

 △Subfloor

  The basis above which you want the new floor to be installed.(e.g. concrete, solid wood, bricks, etc.).

 △Underlayment

A layer placed between the subfloor and surface flooring(usually made of foam, resin, plastic, etc.).

  The flooring mentioned in the "underlayment" segment refers to the floating ones.

  As the glue-down type(LVT) would be directly attached on the subfloor in most cases.

Underlayment: Notion

  Underlayment refers to the layer to be installed between the subfloor and surface flooring(usually made of foam, resin, plastic, etc.)

Different Types of underlayment

  The underlayment could be either:

 1)isolated 

or 

 2)be attached to the surface flooring.

   When isolated from the surface flooring, then usually comes in rolls, you need to calculate the necessary amount and cut it off from the underlayment roll.

   When attached to the surface flooring, it is said to be helpful prevent the flooring from deformation(from the moisture, heat, etc.), and avoid the noise of float floors' minor movements on the subfloor.

Note:

  So when purchase flooring, better purchase the ones with underlayment. Especially when you're to buy SPC floors, laminate floors.