A subfloor is the foundational layer of a floor structure that rests directly on top of the floor joists in a building. It serves as a solid base upon which the finished flooring is installed. Typically made of materials like plywood or oriented strand board (OSB), the subfloor provides structural support and creates a smooth, stable surface for the visible flooring material. In older homes, the subfloor might consist of diagonal planks, while newer constructions often use large sheets of engineered wood products.

The primary purpose of a subfloor is to distribute the weight of people, furniture, and other loads evenly across the floor joists, ensuring structural integrity and preventing flexing or sagging of the finished floor. It also acts as a barrier between the living space and the area beneath, whether that's a crawl space, basement, or the ground itself. In some cases, particularly in homes with concrete slab foundations, the concrete itself may serve as the subfloor. The thickness and type of subfloor material used can vary depending on factors such as the spacing between floor joists and the type of finished flooring to be installed.

The cost to repair a subfloor can vary significantly based on the size of the area that needs repair and the specific conditions of the project. On a per-square-foot basis, homeowners can expect to pay between $2.20 and $4.75 for subfloor repair. For a typical room measuring between 200 and 250 square feet, the total cost generally ranges from $440 to $1,200. This price range accounts for the materials, labor, and any additional work required to ensure the subfloor is properly installed and leveled.

For larger areas, such as a basement ranging from 800 to 1,500 square feet, the costs can be substantially higher. In these cases, the average total cost for subfloor repair can range from $1,750 to $7,100.This broader range reflects the increased complexity and labor involved in repairing larger spaces, as well as the potential need for additional materials and structural adjustments.

While a subfloor can theoretically last indefinitely, realistically, its lifespan may be shortened due to various factors. In cases where a subfloor is damaged or defective, it may only last 20 to 30 yearsbefore requiring replacement. Factors that can significantly reduce a subfloor's lifespan include water damage, prolonged exposure to moisture, poor installation, or the use of lower-quality materials. Regular inspections and prompt addressing of any issues, such as water leaks or structural problems, can help extend the life of a subfloor and prevent premature failure.

The time it takes to replace a subfloor varies depending on the extent of the damage. Replacing a small, damaged area can take a few hours, while a professional contractor working on an average-sized room can take 1 to 2 days.

This timeframe includes removing the old subfloor, preparing the area, installing the new subfloor, and ensuring it's properly secured. However, for larger areas like a basement ranging from 800 to 1,500 square feet, the project could extend to 3 to 5 days or more, especially if there are complications or additional structural work required.

Follow these tips to increase your chances of hiring a qualified and reliable subfloor contractor for your project:

• Experience and expertise: Look for contractors with extensive experience in subfloor installation and repair. Ensure they are familiar with various subfloor materials and techniques.
• Certifications and accreditations: Check for relevant certifications from organizations like the International Certified Flooring Installers (CFI) or the National Floor Covering Association (NFCA).
• Reputation and reliability: Check online reviews on HomeGuide and Google to gauge customer satisfaction.
• Licensing and insurance: Verify that the contractor is licensed and insured to protect yourself from potential liabilities.
• Multiple quotes: Get multiple quotes to compare prices and services.

Remember that the cheapest option isn't always the best; prioritize quality workmanship and the ability to handle unexpected issues.

Ask these questions to assess the contractor’s qualifications, work process, and reliability:

• How long have you been in business?
• Do you have experience with subfloor repairs similar to my project?
• Can you provide proof of your current certifications and insurance policy?
• Can you provide references from previous clients?
• Can you assess the condition of my subfloor?
• What is your approach to repairing damaged subflooring?
• How long have your crew members been with you?
• What is included in your cost estimate?
• How long do you expect the repair to take?
• When would you be able to start the project?
• What type of materials do you use for subfloor repairs?
• Do you offer any warranties on your work?
• How do you handle unexpected issues during the repair process?