How To Install An MDF Subfloor? 6 Steps To The Rescue

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You’ve done a lot of research for your subfloor. You’ve now got the idea that MDF boards are perfect for your subfloor. But what you don’t know is how to install one. This can be a hard process for most people. 

How can you install an MDF subfloor?

Prepare your MDF subfloors first. You have to do this by leaving them in a dry space for 2 days. Once this is done, install temporary spacers between the wall and MDF panels. You then need to attach your MDF panels. After you have attached every panel, fasten them perfectly. Once done, check if there are any squeakers. 

You might still be confused. We get it. Don’t worry, we have the perfect step-by-step guideline only for you. 

Read along to learn more!

Is MDF the Right Choice For Your Subfloor? 

Before you decide to use MDF as your subfloor, ensure you have the full picture. If you search for waterproofing a dog door, you’ll want to know everything about this. It’s the same scenario for this also.  

That’s why let’s see if you can use MDF as subfloors- 

A firm flooring, such as MDF, provides a uniform, flat surface. It’s also resistant to wear because of its high density. 

MDF subfloors are also more comfortable and quieter. MDF can even be readily sawed to match your subfloor perfectly.

Although MDF might seem a perfect fit, it can have some downfalls. It takes screws well. But if the screws are too close to the edges, they’ll break or split. 

Another disadvantage of MDF is its tendency for expanding when wet. As a result, you may need to place a waterproof membrane on your MDF board.

Despite these potential flaws, you can easily overcome them. That’s why all things considered, MDF boards can be perfect for your subfloor. 

Let’s find out how you can install MDF boards as your subfloor now!

How to Install MDF Subfloor?

Before you start your project, we recommend you learn some woodworking tips. Once you’re done, get ready to install your MDF subfloor. 

Necessary Equipment 

In order to go through with this project, go to your hardware store. You’ll need some equipment that is mandatory for this project. Let’s see what they are- 

  • Leveling squares
  • Level
  • Tapping block
  • Table saw
  • Safety glasses

You’ll also require some materials as well- 

  • Interlocking concrete block
  • MDF subfloor

Got them? Let’s start building! 

Step 1: Check The Joists 

Before you set your panels, make sure the joists are straight and square. You should also check if all the blockings are solid or not. Solid blocking makes your subfloor stronger and prone to damage.

Step 2: Prepare Your MDF Panels

Before you start building your subfloor, you’ll need to prepare your MDF boards. This will make the process much easier. 

To do this, you need to leave your MDF panels in a dry space for 2 days. To see how the subfloor panels will fit together, dry fit them first. This stops the end result from becoming a little sliver.

Cut a few inches off the initial row with a table saw to adjust the panels. Make sure you’re cutting in a well-ventilated location. 

We have listed a few good-quality MDF boards for you:

Product 1
Product 2

Feel free to use any of them if you like. 

Step 3: Install the Spacers

Place ¼” spacers between wall and subfloor panels. This will help with expansion and contraction. After the floor is installed, these spacers will be taken out.

To ensure a neat seam, use a tapping block. You should also stagger the seams for a more stable subfloor. 

Step 4: Attach the MDF Boards

You’re all done with the preliminary process. It’s time to start the most important part. That is to attach the MDF boards to your joists. 

You should keep in mind that woodworking can be a dangerous job. So before you start attaching your boards make sure to follow basic woodworking safety rules

But before that make sure to stagger the panels. What this means is, the joints along the forefoot should not be aligned. 

Once you’re done, apply a good thick layer of subfloor adhesive. Do this in a zigzag pattern on each joist. Only apply enough glue for two panels at a time. This will prevent the glue from sticking before installation. 

Apply 1/8th inch of glue along the bottom of the full length of the panel now. Make sure to space them 4 foot edges 1/8th of an inch apart. You can use attendee nails to help with spacing. 

Place the next panel onto the joists and slide the TNG together now. Remember not to jam them. Instead, you can lightly budd the panels together. This will set the placements just right for your panels. 

But you should never hit your panels directly with the hammer. This will destroy the edge and the panel might not join properly. 

Step 5: Fasten Your Panels 

Once you’re done attaching your panels, apply pressure to the areas you want to fasten. Ensure that the panel is tight to the joist. Start fastening at one corner of the panel. Work your way to the edge of the opposite corner. 

Make sure the fasteners are flush with the panel surface. Fasteners should be neither deeper or shallower. Drive each fastener straight down and make sure there are no shiners. 

Make sure the fasteners are placed ⅜ inch deep from panel edges. They should be spaced 6 inches apart along 4-foot edges. The spaces should be 12 inches apart along the center portion of the panel. 

Remember to fasten each panel before moving on to the next panel. Lastly, remove the fasteners you placed in earlier to help with spacing. 

Once you’re done, you can paint your MDF subfloor if you like. Some people also use white paint as a primer before painting the subfloor. 

Step 6: Check For Squeaks 

Once you’ve finished installing the entire floor, check for squeaks.  If there are squeaks, you can add extra fasteners to solve this problem. 

You’re all finished with installing your MDF subfloor. But if you have a high humidity area you have other options as well.

FAQs

Question: Can you use MDF as underlayment?

Answer: Yes, you can use MDF as underlayment. 18-22mm MDF sheets are a high-density material with a uniform polish and resilience.

Question: Can I use MDF under vinyl flooring? 

Answer: Yes, you can. The usage of treated MDF as a flooring surface is not uncommon. It delivers a sparkling, warm underfoot experience with a couple of coats of varnish.

Question: Is MDF suitable for flooring?

Answer: Yes, MDF is suitable for flooring. Unlike many hardwoods, MDF has a higher density. It also resists warping and swelling in high-humidity environments such as restrooms or washrooms. 

Final Word

Now you have the full idea of how you can install an MDF subfloor.  But  You see, it’s much harder to install. But if you think this is too much for you, it’s better to call a professional. 

Good luck with your project!

Melissa Hawkins