How to Install Subfloor: A Step-by-Step Guide

How To Install Subfloor

If you want to install new flooring in your home, it all starts with the subfloor. The subfloor is the layer of material that sits directly on top of the floor joists and provides a stable foundation for the finished flooring. Whether you’re installing hardwood, tile, or carpet, a properly installed subfloor is essential for a long-lasting and beautiful floor.

In this article, we’ll provide a step-by-step guide on how to install subfloor in your home. We’ll cover everything from preparing the room to finishing the subfloor, so you’ll be equipped with all the information you need to tackle this DIY project.

Tools and Materials You Will Need

Securing the subfloor panels tightly ensures stability and prevents creaks and squeaks
Securing the subfloor panels tightly ensures stability and prevents creaks and squeaks

Before you begin installing the subfloor, you’ll need to gather the necessary tools and materials. Here’s a list of everything you’ll need:

Tools:

  • Circular saw or table saw
  • Framing square
  • Tape measure
  • Chalk line
  • Drill/driver
  • Hammer
  • Nail gun (optional)
  • Jigsaw (optional)

Materials:

  • Subfloor panels (plywood or oriented strand board, or OSB)
  • Construction adhesive
  • Screws or nails
  • Underlayment (optional)
  • Sandpaper
  • Floor sealer

Make sure you have all the necessary tools and materials before you begin your project. Having everything on hand will save you time and trips to the hardware store.

Preparing the Room for Subfloor Installation

Before you begin installing the subfloor, you’ll need to prepare the room. Here are the steps to follow:

Step 1: Remove Old Flooring

If you’re replacing an existing floor, you’ll need to remove the old flooring material. Use a pry bar to remove any baseboards and molding, then pull up the old flooring. If the old flooring is glued down, use a scraper to remove any remaining adhesive.

Step 2: Clean the Subfloor

Once the old flooring is removed, clean the subfloor surface thoroughly. Sweep or vacuum up any debris, and then wipe the subfloor with a damp cloth to remove any remaining dust or dirt.

Step 3: Check for Levelness

Use a level to check the subfloor for levelness. If there are any high spots, use a sander or plane to remove them. If there are any low spots, use a self-leveling compound to even out the surface.

Step 4: Mark Joist Locations

Use a framing square and a chalk line to mark the location of the floor joists on the subfloor. This will help you know where to fasten the subfloor panels to the joists.

Installing the Subfloor

Now that you’ve prepared the room, it’s time to start installing the subfloor. Here are the steps to follow:

Measuring and Cutting the Subfloor Panels

Measure the length and width of the room and cut the subfloor panels to fit. Use a circular saw or table saw to make your cuts. Be sure to leave a 1/8-inch gap between the panels to allow for expansion.

Laying Out the Subfloor Panels

Lay out the subfloor panels on the subfloor, leaving a 1/8-inch gap between the panels and the walls. Use construction adhesive on the joists before laying the panels to ensure a secure hold.

Securing the Subfloor Panels

Use screws or nails to secure the subfloor panels to the joists. Make sure to fasten the panels every 6 inches along the joists and every 12 inches along the panel edges. Be sure to countersink your screws or nails so that they don’t interfere with the finished flooring.

By following these steps, you’ll have a sturdy and level subfloor that’s ready for the finished flooring. In the next section, we’ll cover how to finish the subfloor to ensure a beautiful and long-lasting floor.

Installing the Subfloor

Now that you have prepared the room, it’s time to start installing the subfloor. Follow these steps for a successful installation:

Measuring and Cutting the Subfloor Panels

Measure the length and width of the room and calculate the square footage of the space. This will help you determine how many subfloor panels you’ll need. Be sure to add extra panels to your order to account for any mistakes or waste.

Using a circular saw or table saw, cut the subfloor panels to size. It’s essential to measure accurately and cut the panels precisely to ensure a tight fit.

Laying Out the Subfloor Panels

Start by laying out the first row of subfloor panels along one wall of the room. Leave a 1/8-inch gap between the panels to allow for expansion. Use a framing square to ensure that the panels are square to the wall.

Continue laying out the subfloor panels row by row until you’ve covered the entire floor. Stagger the panels so that the seams don’t line up, which will create a stronger and more stable subfloor.

Securing the Subfloor Panels

Apply a bead of construction adhesive along the top of each floor joist, then lay the subfloor panel in place. Use screws or nails to secure the panel to the joists, making sure the screws or nails penetrate the joists by at least 1 inch.

Continue securing the subfloor panels in place until all the panels are installed. Be sure to check for any gaps or loose panels and fix them as needed.

Finishing the Subfloor

Once the subfloor is installed, it’s time to finish it. Here are the steps to follow:

Sanding and Sealing the Subfloor

Use sandpaper to smooth any rough spots or seams in the subfloor. Then, apply a floor sealer to the subfloor. This will protect the subfloor from moisture and help prevent warping or swelling.

Adding Underlayment

If you plan to install hardwood or laminate flooring, you’ll need to add an underlayment over the subfloor. Underlayment provides a smooth surface for the finished flooring and can help reduce noise and moisture.

Choose an underlayment that’s appropriate for your flooring type and follow the manufacturer’s instructions for installation.

By following these steps, you’ll have a properly installed subfloor that’s ready for your finished flooring. With a little bit of planning and effort, you can tackle this DIY project and enjoy a beautiful and long-lasting floor in your home.