Yes, tongue and groove flooring generally needs an underlayment. While it provides a tight interlocking fit, underlayment is highly recommended to act as a moisture barrier, reduce floor squeaking and friction, and provide sound insulation.
Don't Skip Out On the Underlayment
As a floating floor, tongue and groove flooring does not need to be attached to the subfloor. However, if you don't add an underlayment between the subfloor and the panels, you can run into several problems. Most notably, your floor will squeak and bend as you walk across it.
Tongue and groove (T&G) underlayment features interlocking edges—a protruding "tongue" and a corresponding "groove"—that lock adjacent panels together. This design creates a seamless, rigid base, distributes weight evenly across seams, and prevents floor squeaking, movement, and uneven edges.
Tongue and groove (T&G) flooring is generally accessible for beginners, though it takes more effort than modern "click-lock" or "glueless" laminate floors. Planks slot together like puzzle pieces, but require fastening to the subfloor via nails, glue, or a combination of both.
Yes, you can absolutely install tongue and groove (T&G) over drywall. It is an excellent way to cover up damaged walls or ugly ceilings without the mess and hassle of tearing out the existing material.
Start at one bottom corner of your wall and make sure that your first board is level by using a hand level or a laser level. The tongue of the board should be facing up towards the ceiling while the groove faces down towards the floor.
Tongue and groove wood is a nice alternative to drywall, you would not need drywall underneath. The initial purchase price of wood is always more expensive than drywall, but by the time you factor in labor for finishing drywall - mudding, taping, sanding, priming and painting, the cost starts to even out.
For most home projects in the Bay Area, there's a clear winner for the best plywood for subflooring: CDX tongue-and-groove (T&G) panels. The "CDX" grade offers the strength and moisture resistance you need. The T&G design locks the panels together, creating a solid floor that helps prevent squeaks.
Installing tongue and groove (T&G) involves securing the planks to a wall or ceiling joists using a "blind nailing" technique. You start with the first board level, nail it through the tongue at a 45-degree angle, and lock the next board’s groove over it. This hides the fasteners completely.
In addition, tongue and groove wood can be used for both decorative and functional purposes, depending on the type of wood and the finish applied. However, there are also some disadvantages to using tongue and groove wood. One disadvantage is that it can be more expensive than other materials, such as drywall.
While you can glue tongue and groove together, it is not recommended to glue the wood under the floor as well. This is because wood floors need room to move when they expand. If the wood is glued to the floor as well as between the planks, there will be no room to move.
The "Rule of 3" in flooring is a design principle that recommends using no more than three distinct flooring materials or color variations throughout your entire home. Limiting your design to three elements creates visual cohesion, prevents a chopped-up layout, and ensures smooth, intentional transitions from room to room.
Water-tight: With proper coating, tongue and groove can even be water-tight. This applies to site-finished flooring, not pre-finished. Lower cost: Products that are made for tongue and groove installation are less expensive than other floor options.
Without an underlayment, you may notice more sound when walking on floors. Remember that underlayment helps to absorb sound, so without it, footsteps and other noises can become much louder. Moisture-related complications: Underlayment acts as a barrier against moisture that can seep through the flooring planks.
Shiplap is typically more affordable than tongue-and-groove, thanks to its simpler profile and easier installation. Labor costs may be lower, especially for DIYers. However, final pricing depends on material type, room size, and even regional rates.
It is highly recommended to glue the tongue and groove (T&G) joints of your subfloor, especially if you are screwing it down. Doing so creates a strong, unified floor deck. However, always prioritize gluing the panels directly to the floor joists, which is the most critical step to prevent future squeaking.