How to properly seal the joint between the bathtub and the wall?

Why do gaps appear?

A gap is a completely natural phenomenon, albeit unpleasant. The reasons for its occurrence can be conditionally divided into two types: during the installation of the bathtub and as a result of its operation.

• Wear. Over time, the grout or any other type of sealing of the joints wears out and will need to be replaced. Nothing can be done about it and you will just have to accept this fact. Yes, you can influence the service life, but nothing lasts forever.
• A similar situation can happen with the bathtub itself. As a result of operation, the bathtub body or base can be damaged. In the case of the base, it is enough to fix the malfunction and then look at the situation – perhaps you will be lucky and everything will get by with a slight repair, or you may have to do everything again. And if the bathtub is already broken, then most likely you will need to call a specialist.
• Uneven adjoining sides (floor or walls). At the stage of rough finishing, pay special attention to leveling the walls and it is advisable to do a test fitting. If you find unevenness in the finished repair, you can try to solve the problem with the help of a frame or by adjusting the legs of the bowl. But with uneven walls, the only thing left to do is to minimize the joint.
• Mismatch of the dimensions of the bath and the size of the room. The most obvious and reliable solution is to install a frame. Large gaps can be functionally played up – for example, by making shelves for storage.

How to seal large gaps?

I consider wide gaps to be gaps larger than 50 mm. The problem is solved by constructing a box along the sides of the bath from brick, foam blocks or plasterboard. This will be part of the rough finishing, then you will need the finishing.

What to do with a medium-sized joint?

It is generally accepted that such gaps are between 5 mm and 50 mm. To close them, you can use any of the following methods.

Inner corner

If you are tiling the walls in the bathroom, purchase a special insert along with it – an inner corner made of plastic or aluminum. It is fixed tightly to the bathtub, and the tiles are installed on top.

The main advantages of this method are reliable sealing, hygiene, and an aesthetic appearance. Disadvantage – installation only during renovation. You will not be able to use this method in a finished bathroom.

You will need: a corner, a stationery knife or saw, tile adhesive, tiles, grout.

How to install a corner between a bathtub and tiles:

1. Mark and cut the planks to the required size.
2. Apply tile adhesive to the wall.
3. Install the corners over the bathtub and secure them with glue.
4. Insert the first row of tiles into the grooves of the glued corners, glue it to the wall.
5. Lay the remaining rows, leave for a day.
6. Decorate the cracks with grout after the adhesive dries.

The photo shows an example of installing an internal corner under the tile

Ceramic or PVC border

To decorate the gap, borders are often used over the bathtub. They are made of plastic or ceramics, the former are suitable for PVC panels, we will talk about them in the next section. The latter are for ceramic tiles, we will focus on them.

The disadvantages include the difficulty of replacing the bathtub and the need for special tools for the job. The main difficulty when installing ceramic borders is trimming to the desired size and cutting holes for pipes and plumbing. A grinder with a diamond disc will do the job best. In addition, you will need: a spatula, tile adhesive, sandpaper, a rubber or wooden mallet, and sealing silicone.

The photo shows decorating a joint with a ceramic border

Tip: to make the finished bathtub look beautiful, match the width of the borders to the width of the tiles and install them end to end.

1. Clean and degrease the surface, wipe dry.
2. Prepare the tile adhesive according to the instructions on the package.
3. Start from the corner. Cut 2 adjoining elements at 45 degrees to each other, sand.
4. Coat the back of the border with adhesive, put it in place, remove excess.
5. Repeat for the second part.
6. Continue in the same spirit, using a mallet to adjust the parts to each other in height.
7. After the glue has completely dried, it is recommended to seal the cracks with grout.

You can also make a ceramic skirting board yourself: to do this, cut the tiles into pieces of the desired height and install them according to the same instructions. It is convenient to use this method over cement mortar laid in a slide.

Plastic skirting board

The main advantages of modern plastic are low price, ease of installation, and aesthetic appearance. You can install this over any decorative finish.

Before starting work, prepare masking tape, a measuring tape or ruler, adhesive sealant, and a stationery knife.

1. Clean and thoroughly degrease the surface.
2. Glue paper tape to the wall and the edge of the bathtub, leaving the width of the border.
3. Fill the empty space with sealant, leave until dry.
4. Cut the skirting boards to the required sizes.
5. Glue with the same sealant or liquid nails.
6. Install the plugs.

Wait until the bathtub is completely dry for 24-48 hours before using it.

Self-adhesive border tape

One of the fastest and easiest ways to finish the gap between the wall and the bathtub is a closing tape. All you need is the roll itself and a spatula for forming the corner (often included in the kit). Another advantage of the border tape is the sealant in the composition, which allows you to save time and money.

Step-by-step installation instructions:

1. Wash and degrease the surface.
2. Remove the protective film from a small area.
3. Press the border with the adhesive side to the wall and bathtub, starting from the corner and forming the corner with a spatula.

Tip: To make the material more elastic, heat the border tape with a hair dryer during installation.

Mounting foam

This method of sealing the joint between the bathtub and the wall is used exclusively as a rough one, because even a waterproof composition in the bathroom needs additional protection. This option is suitable if the distance from the bathtub to the wall does not exceed 3 cm. The advantages of polyurethane foam include its ability to expand and dry quickly. The downside is that you need to work extremely carefully, because it is incredibly difficult to wash the composition off your hands and walls.

To seal the gap, you will need: a mask, gloves, a degreaser, masking tape, waterproof foam, a syringe gun, a stationery knife.

Step-by-step instructions for the process:

1. Spread film or newspapers on the floor.
2. Clean the walls and sides of the bathtub, degrease.
3. Glue paper tape around the surface to be treated.
4. Put on gloves and a mask.
5. Shake the can, then insert it into the gun.
6. Pour the foam into the joint quickly and carefully, leave until completely dry.
7. Cut off the excess with a stationery knife.
8. Trim the top using any decorative method.

A sealant is usually applied over the mounting foam, and ceramic or plastic skirting boards are installed.

Cement mortar

For large gaps between the bathtub and the wall, cement mortar is used. The advantages of cement mortar include its low cost, ease of installation and reliability. Among the disadvantages are the need for waterproofing and an unattractive appearance. Like mounting foam, cement is a material for rough repairs. Tiles, plastic corners or border tape are attached on top of it.

For the cement mortar method you will need: dry mix, water, spatula. If the gap is larger than 1 cm, use temporary formwork or plastic mesh to prevent the mass from falling through. It is installed before work begins and removed after drying.

1. Clean the surface where you plan to apply cement.
2. Dilute the mixture to the consistency of thick sour cream.
3. Wet the surface of the bathtub and wall to improve adhesion.
4. Apply the solution with a spatula, tamp it as you add it.
5. Leave until completely dry.

Tip: For additional water drainage in the bathroom, lay the cement at an angle and glue the tiles on top.

After the cement plaster has dried, it must be insulated with a water-repellent impregnation. Only after this can the resulting joint be decorated.

The photo shows rough finishing of the joints in the bathroom

How to seal a narrow gap?

This category includes joints no more than 5 mm. If desired, you can use methods for medium ones, but this is at your discretion.

Sealant

The most simple and universal way to seal a narrow gap is a sealant. It is suitable for joints no more than 5 mm. In other cases, you will have to choose another method or combine silicone sealant with other building materials – mounting foam or cement. The only thing is that sealants come in different types and, accordingly, it is better to use the most suitable one for different coatings. Below I have prepared a table with recommendations for choosing a sealant:

Resistant to temperature changes.
Elastic.
Dries in 3 hours.

Elastic.
Higher adhesion than all the others.

To decorate the joint you will need: a degreaser or solvent, masking tape, a syringe gun, a sealant and a soft spatula or brush.

The photo shows filling a narrow gap with sealant from a special gun

1. Pour water into acrylic bathtub (skip this step for cast iron bathtubs).
2. Clean the surface from dirt and dust, degrease it.
3. Paste the tiles and the bathtub surface with masking tape, leaving a 5-7 mm corner.
4. Insert the sealant into the gun, go over the joint in one go. Do not make a second layer, this will lead to surface defects.
5. Remove excess with a spatula or brush dipped in soapy water and smooth the surface.
6. Leave to dry for 24 hours, remove the tape, drain the water.

Important: Do not use the bathtub for its intended purpose while it is drying.

Grouting

One of the easiest ways to seal the joint between the bathtub and the tiles is to use what you already have at home. Surely, after grouting the seams between the tiles, you have some mixture left. But be careful: this method is only used on joints no more than 0.5 cm.

Tip: To make the overall look aesthetically pleasing, use the same shade of grout as on the tiles. Most often, this is a contrasting classic white or any other color in the color of the tiles.

The only drawback of grout is the appearance of rust, mold and dirt after some time. To avoid this, use the impregnation for tile joints “Fuga-shine”. It glazes the surface, makes it smooth, protects from moisture and stains.

The list of works for grouting gaps near the wall is the same as for the joints between tiles. Prepare the mixture itself, water, a container, a rubber spatula and a sponge. The correct order of actions:

1. Clean the gap from dirt and dust.
2. Wet the surfaces with primer.
3. Dilute a small amount of grout.
4. Fill the gaps with a rubber spatula. Hold it at a 45-degree angle and press as hard as possible to seal the joint.
5. Wipe off excess mixture with a damp sponge no later than an hour after finishing the work.

If you are going to treat the gap with “Fuga-gloss”, wait 72 hours until it hardens completely and apply the composition with a brush. Remove excess with a dry cloth.

The photo shows the joint between the bathtub and the tiles made of grout