Different types of materials are available for the bathroom subfloor. It is like a base under the finished floor that adds strength and a flat surface for vinyl or ceramic tiles.
Can You Use OSB For Bathroom Subfloor? OSB is not an ideal choice for a bathroom subfloor because it can absorb moisture and cause swelling, especially at the edges. The panels are heavy, cause cracks on the ceramics and vinyl tiles, and are challenging to paint. Plywood or enhanced plywood is the common and preferable choice for bathrooms because it does not swell in a moist atmosphere.
The durability and performance of the subfloor depend on the material you select for it. For example, you can use enhanced OSB instead of normal OSB because it uses wax and resins in its manufacturing to withstand moisture in damp places.
Why should you not use the OSB for bathroom subfloor?
Oriented strand board, also known as OSB, is like an engineered wood that is made of different wood strands, which are glued together with adhesives to use its roof covers, walls, and subfloor of less moist places but is not preferred for bathrooms.
Bathroom renovation is one of the challenging tasks, especially when you are planning to change or renovate the subflooring because moisture and humidity are the constant factors to occupy this place.
It can absorb moisture and water when wet and takes a long time to dry. The wood used in manufacturing gets swollen from the edges and warps around due to excessive moisture.
The area around the shower and bathtub is more likely to get wet, and the subfloor can cause problems with the outer finishing.
The adhesive used between the wood strands plays a significant role because it will allow the moisture to absorb in the space between them if the quality of the glue is poor. As a result, it holds water for a longer period and causes the wood to decay due to humidity.
The humidity causes mold and mildew growth on the subfloor and affects its durability by rooting the inside wood.
The thickness of the OSB panel is one of the main reasons for swelling and warping from the corners and sides.
The average weight of a 4×8 feet panel sheet is approximately 75-80 pounds which is difficult to deal for a single person.
In addition, you have to hire two or more professionals to deal with OSB subflooring because cutting ad installation is not easy for a single person.
It can put more stress and pressure on the house due to its large weight and requires more hard work to install it.
In addition, many wood strands are glued together with a lot of pressure, which causes the heavy weight of the wood strands.
Although it is expensive, the loader can cost you more to bring it to your house. In addition, it requires special tools to cut and install this subflooring into your bathroom.
Cracks on ceramics and vinyl tiles
The wooden panels soak water and swell more when exposed to a humid environment. It causes an uneven surface which leads to cracks on ceramic and vinyl tiles.
It can make the surface irregular and soft and does not withstand heavy traffic and more load on its surface.
In addition, high moisture causes the adhesive between the panels to become potentially weak, leading to the movement of tiles from the floor.
OSB wood is hard and heavy but not strong and much durable, especially in a damp atmosphere. However, strong and stiff flooring under the tiles can prevent cracks and make them last longer.
Difficult to paint
OSB sheets are made of wood that will absorb the paint, and they cannot stand water-based paints.
The surface texture of the wood is not smooth enough to paint it easily and can soak the paint into the wood.
However, it is not impossible to paint it, but you need to use a specific type of paint and tricks to do this task.
For example, water-based paints can start peeling off over time if you do not use any primer before painting the wood strands.
The water-resistant primer can help the paint to stand longer and resist moisture, as two to three coats of oil-based primer can prevent humidity and paint from soaking into the wood.
What is the best material for a bathroom subfloor?
It is better to consider some essential factors before selecting a material for the bathroom subfloor.
Plywood or enhanced plywood is considered the best material for this purpose because of the many benefits of the wood used in its manufacturing.
It is more expensive than OSB, but it is worth spending money on a better-quality material that can withstand the bathroom environment. For example, plywood costs approximately $20-$25, while OSB ranges from $15 to $17 per 4×8 feet sheet.
It is more durable than OSB as the plywood that is made from 100% natural wood can last up to 30-35 years. It has more moisture tolerance than OSB but is not 100% moisture resistant and can dry faster than other products if exposed to humidity and a damp atmosphere.
Enhanced plywood is coated with high water-resistant resins to make it more reliable in a moist environment. It does not swell and warp permanently and is much stiffer and stronger than OSB wood panels.
This makes the floor sturdier and more rigid to adjust the tiles and avoid any cracking and slipping of tiles. It is suitable for all kinds of flooring, such as tiles, ceramics, stone, and vinyl tile flooring.
It comes in various sizes, and you can also paint it with mildew-resistant paint to give it a pleasing look and prevent rooting due to mold and mildew.
It has more holding power for the nails and screws and is easy to install as compared to OSB. A plywood subfloor can increase the resell value of your house as it can last longer and is more suitable for a bathroom.
Things to consider for bathroom subflooring
Bathroom subflooring is something that can last as long as the house itself, but it requires proper care and attention when selecting the material for it.
Moisture and humidity are the enemies of the durability of wood materials because of the wood’s nature to soak water.
It is better to consider a more resistant material because you use water frequently in the bathroom to wash your hands and face.
Try to wipe the water from the floor as soon as you take a shower or after using the bathtub. The water splashes, and moisture can get absorbed if you do not clean it regularly.
Make sure to turn on the exhaust fan and open the windows for ventilation because the damp environment will affect its durability no matter which material you have used for the subflooring.
You can apply a high-quality primer on its surface to prevent mildew and mold that can cause rooting inside the wood sheets.
Do not add much space between the panels, which can cause slipping and movement when you walk on the floor.
Do not lay several panels together when applying the adhesive because the time delay in arranging them can cause the glue to dry or soak into the wood and affect its performance.