Do I Need To Waterproof My Kitchen Floor? (Solved!)

Right after bathrooms, kitchens are the most vulnerable spaces to moisture issues or water damage, you have a lot to gain from considering this point when flooring these areas.

Waterproofing your kitchen floor isn’t exactly a must. A lot of people simply install water-resistant flooring in their kitchens, this is not as effective as waterproofing but it does a decent job at preventing water damage.

If you’re a bit confused about the difference between waterproof flooring and water-resistant flooring, here’s a quick breakdown.

Waterproof flooring is made of sturdy non-porous materials, it cannot absorb water or liquids, this type of flooring is perfect for bathrooms and kitchens.

Water-resistant flooring, on the flip side, is a bit porous, so it can absorb water but not as fast as flooring options that are not resistant to water.

Now that we’ve gotten this out of the way, here’s everything you need to know about waterproofing your kitchen floor.

Waterproof My Kitchen Floor

Should You Waterproof the Subfloor Before Flooring?

A subfloor needs to be protected from water among other things. If water is able to get past this foundation, it can weaken the joists of your floor base, and cause serious damage, so waterproofing this structure is necessary.

The implications of failing to waterproof your subfloor are as follows, mold and mildew growth, pest infestation, and structural decay.

Subfloors come in different types, the most common are:

  • Concrete subfloors
  • Particleboard subfloors
  • Plywood subfloors
  • Softwood subfloors

All types of subfloors require some form of waterproofing before a finished flooring is installed. You mustn’t confuse a subfloor for an underlayment.

The structure installed above or on top of a construction floor is called a subfloor, it is the leveled surface you place your finish flooring on.

An underlayment, on the other hand, is the thin cushion-like sheet between your finish flooring and subfloor, it serves as a sound insulator and it’s meant for floors above ground level.

It is also worthy of note that a moisture barrier and an underlayment can be combined to form one product.

Do You Need to Waterproof Under Tile?

As hard as it is to believe, tiles aren’t waterproof and neither is the grout, used to reinforce them, due to this, it is very necessary to waterproof the substrate underneath.

Certain types of tiles are water-resistant, while others are not. For instance:

  • Ceramic and porcelain tiles aren’t so porous so water can’t easily seep through them.
  • Natural stone tiles and travertine tiles, on the other hand, are pretty penetrable so, moisture can easily pass through them.

There are several ways to go about waterproofing underneath your tile floors, the approach you use depends on what your subfloor is made out of, here are all the methods.

1. Waterproofing Using a Waterproofing Membrane

The most common way to waterproof under a tile floor is by applying a continuous layer of a waterproofing membrane on the subfloor.

Before you install this moisture barrier, ensure that you prime the surface of your subfloor, this would ensure that the membrane sticks on well.

Also, the waterproof sealing tape is one material you mustn’t neglect, it keeps your membrane joints tightly fastened together and can be used to seal off corners that are hard to cover.

2. Waterproofing Using a Decoupling Mat

Decoupling mats are best used on subfloors made of plywood, OSB, and MDF, they keep installed tiles from cracking by absorbing stress, and these barriers are also waterproof.

All you need to do to install a decoupling mat is, cut it to the size of your floors, apply some adhesive to your subfloor, apply your mat and seal off the exposed areas with some waterproofing strip and sealant.

3. Waterproofing Using SBR

If you’re going to be tiling over surfaces like plasterboards and bitumen, then this waterproofing method is your best bet.

SBR stands for Styrene Butadiene Rubber, it is a bonding agent that can be used as a moisture barrier.

PVA (Polyvinyl acetate) shouldn’t be used as an alternative to SBA because, whether it’s dry or wet, it is water-soluble.

Do You Need to Waterproof Under a Wood Floor?

You not only need to waterproof under a wood floor but also on top of it. Wood floors, especially unfinished ones, are susceptible to water damage and should have their surface and subfloor sealed.

Most DIYers use polyurethane or oil-based finish to protect the surface of their wooden floors from moisture issues or water damage.

Waterproofing underneath a wooden floor, on the other hand, requires a different approach from the one detailed above.

You can install a wood floor, by floating, gluing, or nailing. The method of installation you decide on determines how you go about waterproofing the subfloor.

With that said, let’s take a look at the various ways to waterproof underneath a wood floor.

1. Waterproofing Under Floating Wood Floors

Floating wood floors are super easy to install, all you have to do is lock each board together. Waterproofing underneath this type of flooring is pretty simple.

Apply your waterproofing membrane or moisture barrier to your subfloor, seal the exposed areas and install your floating floors.

2. Waterproofing Under Nailed Wood Floors

Using a waterproof sheet or membrane underneath wood floors that are meant to be nailed down wouldn’t work because the nails are going to puncture the moisture barrier.

To successfully waterproof underneath wood floors that require nailing, install the moisture barrier underneath the subfloor.

3. Waterproofing Under Glued Wood Floors

A waterproof membrane and underlayment should go underneath a wood floor that needs to be glued down.

The process is quite easy, stick your waterproofing membrane to the subfloor underneath, cover up the exposed area with some sealing tape, then proceed to glue on your floorboards.

You can make use of a moisture barrier that is also an underlayment to make the installation process easier.

Why Should You Waterproof Before Tiling/Wood?

Waterproofing before tiling or installing wood floors comes with a handful of benefits, which have been listed below, the only plausible demerit to this process is that it isn’t cheap.

A lot of people think that the only thing a moisture barrier does is protect your floors from water damage, but this is inexact.

Here’s everything you have to gain from waterproofing beneath your finish or new flooring. 

1. Little or No Pest Issues

Installing a waterproof layer underneath your wood floors or tiles reduces the chances of pests infesting your home.

Water-damaged floors attract a lot of creepy crawlies like ants, centipedes, termites, and spiders.

So, waterproofing your subfloor is a very necessary step to not only protecting your floors but your home.

2. Hindered Mold and Mildew Growth

It’s common knowledge that mold and mildew grow on moist or damp surfaces, and can deteriorate one’s health over time.

Waterproofing your subfloor lowers the chances of these organisms developing underneath your flooring and spreading to other parts of your home.

3. Well-Protected Flooring Structure

Your floorboards or flooring is supported by a structure known as a subfloor, and then the subfloor is supported by floor joists.

Failing to protect these structures from water damage can lead to the rot and decay of your floor base, which is super risky.

How Do You Waterproof a Kitchen Floor?

Protecting your kitchen floor from water damage is quite easy, there are several ways to go about it, below you will find a step-by-step guide on the most common method.

Materials or tools you will need,

  • A broom
  • Primer
  • Paint pot
  • Paint roller
  • Paintbrush
  • Gloves
  • Silicone Caulk
  • Spatula
  • Masking tape
  • Waterproofing bonding agent
  • Waterproof sheet or membrane

Step #1: Clean Your Kitchen Floor

Using a broom, thoroughly sweep your kitchen floor to get rid of dust particles or grime, doing this would prepare your floors for priming.

Also, ensure that your room is well-ventilated as you’ll be working with chemical compounds that emit strong fumes.

Step #2: Coat Your Floors with Primer

There are specially formulated primers that can only be used on specific materials and there are all-purpose primers that can be used on almost any surface.

Choose a primer from a reliable brand and pour some into your painter’s pot, if the product you chose requires dilution before application, add some water to the treatment.

Once you’ve done the necessary, use a paint roller to apply the primer to your kitchen floor, start from the corner furthest from the exit.

Apply some primer to the lower part of your kitchen wall to ensure that the waterproofing process is thorough.

After coating your kitchen floor and a portion of your kitchen wall with primer, wait for it to dry.

Check the time specified on the primer to know exactly how long you’d have to wait.

Step #3: Seal Off Cracks with Silicone

Once the primer dries completely, get your waterproof silicone caulk and proceed to fill every crack or gap in your subfloor.

Use a spatula to scrape off excess caulk, then wait for the application to dry. Make sure you check the label of your silicone caulk to have an idea of how long it’d take to dry.

Step #4: Use Masking Tape to Mark Off Lower Walls

You’re going to be waterproofing not just your floors but the lower portion of your walls, so you must mark around your walls with tape.

The tape will also prevent the adhesive from being applied unevenly and too high up your walls.

Step #5: Apply Waterproofing Agent

After you’ve taped off the area you’d like to waterproof, take your paint roller or a brush and dip it in some waterproofing agent.         

Apply the agent thoroughly to the lower part of your kitchen wall and your kitchen floor. Ensure that you start applying the agent from the furthest corner of the door.

Step #6: Apply Waterproofing Membrane

Unroll a strip of waterproofing membrane and lay it flat on your waterproofing agent-coated floor to get the perfect sizing.

Once you get the right size, cut the membrane with scissors and coat it with some waterproofing agent to adhere it properly to the floor.

Continue applying the membrane to your floor, until everywhere is covered up, make sure you apply more than one layer of the waterproofing membrane.

Step 7: Install Your Flooring

The membrane should take about a day or two to cure, once the drying time elapses, proceed to install your finished flooring.

Do not carry out this step until your floors are completely dry.

Final Thoughts

Waterproofing your kitchen floor isn’t a complicated task, with the right tools or materials you should be done with this project in under a week.

Do not rush over the steps, ensure that all your applications and modifications are thorough and neat.

A single mistake in the installation process can render your barrier useless.