Selecting the right subfloor for your basement is an important decision that will impact the long-term performance and durability of your finished basement space. There are four main types of basement subflooring to consider, each with their own benefits and drawbacks. This article will examine the pros and cons of the four most common basement subfloor options to help you make an informed decision for your basement remodeling or finishing project.
Plywood Subfloor
Plywood is a popular choice for basement subfloors. Here are some of the benefits and considerations when using plywood as a basement subfloor:
Benefits of Plywood Subfloor
- Affordable – Plywood is one of the most budget-friendly subfloor options. It is readily available at home improvement stores.
- Easy to Install – Plywood subfloor panels are lightweight and easy to cut to size. They can be installed with screws or nails.
- Provides Solid Base – Plywood creates a uniform, stable surface for flooring materials installed on top. It helps prevent imperfections in the finished floor.
- Withstands Moisture – Plywood is more resistant to moisture than OSB (oriented strand board). It holds up better if water seeps into the basement.
Drawbacks of Plywood Subfloor
- Prone to Swelling – Although it withstands moisture better than some alternatives, plywood can warp or swell if exposed to excessive moisture over time.
- Not Ideal for Below-Grade – Plywood is better suited for above-grade subfloor applications. Other materials are specially designed for basements.
- Can Squeak Over Time – Plywood subfloors may begin to squeak as they age, which can be annoying. Proper fastening during installation can help minimize this.
- Voids May Telegraph – Any surface defects, knots, or voids in the plywood can sometimes telegraph through finished flooring over time.
Tips for Installing Plywood Subfloor
- Use at least 3/4″ tongue-and-groove plywood for maximum stiffness.
- Allow 1/8″ spacing between panels for expansion.
- Stagger plywood joints like brickwork and avoid aligning edges.
- Fasten panels every 6-12 inches along edges and every 12 inches in field.
- Use screws or ring shank nails to avoid popping over time.
- Ensure plywood is dry before installation – no more than 18% moisture content.
OSB Subfloor
Oriented strand board (OSB) is another sheet good option for basement subflooring. Here are some pros and cons:
Benefits of OSB Subfloor
- Very Affordable – Typically cheaper than plywood. Can save significantly on material costs.
- High Strength – OSB is engineered for strength. It holds up well underfoot when installed properly.
- Panels are Uniform – Made of wood strands glued in cross-hatch layers, so less prone to warping.
- Easy Installation – Lightweight, easy to cut and fit like plywood. No special tools needed.
Drawbacks of OSB Subfloor
- Not Moisture-Resistant – OSB swells and delaminates easily when exposed to moisture and humidity.
- Avoid Below-Grade – Only suitable for basement subfloors if protected by a vapor barrier.
- Can Develop Soft Spots – OSB is prone to deterioration and compression when subjected to sustained moisture.
- telegraphing Possible – The wood strands in OSB panels may sometimes telegraph through finished flooring.
Tips for Installing OSB Subfloor
- Apply plastic vapor barrier under OSB panels to protect from ground moisture.
- Use tongue-and-groove panels for a tight seam fit.
- Gap panels 1/8 inch for expansion.
- Offset seams like brickwork and stagger panel joints.
- Fasten every 6-12 inches along the perimeter and every 12 inches in the field.
- Use ring shank or screw shank nails to avoid nail pops.
AdvanTech Subfloor
AdvanTech is an engineered wood panel made by Huber Engineered Woods specifically for structural subflooring applications below-grade. Here’s an overview:
Benefits of AdvanTech Subfloor
- Moisture Resistant – AdvanTech uses water-resistant additives to reduce swelling from ground moisture.
- Consistent Quality – Factory made with quality control, as opposed to solid sawn lumber with natural imperfections.
- Stiffness and Strength – Engineered to provide enhanced stiffness for floors compared to OSB.
- No Telegraphing – Multi-layer construction prevents strand telegraphing on the surface.
Drawbacks of AdvanTech Subfloor
- More Expensive – Typically costs more than basic OSB or plywood.
- Limited Availability – Found at select home improvement stores or may need to special order.
- Heavier and Thicker – AdvanTech panels are heavier than plywood or OSB, making them trickier to install.
Tips for Installing AdvanTech Subfloor
- Have two people carry panels due to weight.
- Use 1/8″ spacing between panel joints.
- Offset seams between rows. Avoid aligning edges.
- Fasten every 6-12 inches around perimeter and every 12 inches in field.
- Use nails or exterior-grade screws.
- Install vapor barrier under panels to protect from ground moisture.
Prefabricated Subfloor Panels
Prefabricated basement subfloor panels make installation fast and easy. Here’s an overview:
Benefits of Prefab Subfloor Panels
- Fast Installation – Prefab panels click or lock together over vapor barrier for fast installation.
- Floats Over Concrete – No nails into concrete slab required. Panels float over the vapor barrier.
- Moisture Resistant – Factory applied moisture barrier protects panels from ground moisture.
- Minimizes Labor – Large panels cover more area faster than traditional plywood or OSB.
Drawbacks of Prefab Subfloor Panels
- High Material Cost – Prefabricated panels cost significantly more than sheet goods.
- Heavy and Bulky – Large panels are heavy, difficult to handle, and require 2+ people to carry and install.
- Prone to Surface Imperfections – Prefab panels can sometimes show slight imperfections on the surface.
Tips for Installing Prefab Subfloor
- Have multiple people to help carry and install panels.
- Follow all manufacturer’s instructions for proper installation.
- Use weight distribution boards under panels if floor is uneven.
- Tap panels together tightly to eliminate gaps before locking.
- Use shims between concrete and panels if needed for level finish.
FAQs
Below are some frequently asked questions about basement subfloor options:
What thickness of plywood should I use for basement subflooring?
3/4″ tongue-and-groove plywood is recommended for best stiffness and preventing floor squeaks. 5/8″ can work for shorter joist spans under 16 inches.
Is green treated plywood good for basement subfloor?
Pressure treated plywood is not necessary for interior basement subfloors. The chemicals used to treat plywood can actually off-gas inside the home. Untreated plywood is recommended.
Should I use OSB or plywood in a damp basement?
Plywood is the better choice for damp basements since it resists moisture better than OSB. If using OSB, be sure to couple it with a vapor barrier.
Is AdvanTech subfloor worth the extra cost?
In damp basements prone to moisture issues, AdvanTech is worth the investment. For drier basements, OSB or ply on a vapor barrier will suffice.
How do I install prefab subfloor panels?
Install vapor barrier first, then interlock the tongue-and-groove panels together over the barrier. Use shims if needed for a flush floor. Fasten panels together but do not nail into concrete.
What is the best subfloor for laminate flooring in a basement?
Plywood or AdvanTech provide a smooth, stiff surface needed for laminate flooring. Prefab panels also work well. Avoid OSB unless protected by a vapor barrier.
Conclusion
When selecting a basement subfloor, consider moisture resistance, cost, ease of installation, and how prone the material is to telegraphing imperfections or making noise. Plywood offers an affordable and versatile option in many basements. For wetter areas, AdvanTech or prefab panels are worth the investment. With the right subfloor in place, you can create a durable, quality finished floor that will last for years.