What is a waterproofing agent and how to use it on terraces, walls and roofs?

You may have heard this word before, but you're not entirely sure what a waterproofing product is or what it's used for. Waterproofing is often one of those tasks that gets put off until the first damp patches or an unexpected leak appear.

If you have dampness, leaks, or need to waterproof your pool or terrace and aren't sure what a waterproofing product is or how to use it on different surfaces, keep reading. In this article, we'll tell you everything.

What is a waterproofing agent and what is it used for?

When it comes to protecting a home from moisture or leaks, the first thing you need to know is what a waterproofing coating is. It's not simply a paint applied to the wall or floor, but a product designed to create a barrier that prevents water or moisture from seeping into the materials.

It can be used in many areas: walls, terraces, roofs, swimming pools, ceilings, or even wood, and is key to keeping the house in good condition over time.

In addition to preventing leaks or seepage, a waterproofing product protects building materials, improves insulation , and prevents the growth of mold or moisture stains. In short, it's an essential ally for maintaining the structure and appearance of any building.

Types of waterproofing

When deciding how to waterproof a surface, it's important to understand the different types of waterproofing available. A thorough understanding of what a waterproofing product is means learning that each area requires a different treatment and that there is more than one type of product for each surface.

Acrylic waterproofing

These are among the most widely used due to their ease of application. They can be spread with a brush or roller and form an elastic film that adapts to the material's movements. They work very well on terraces, flat roofs, or terraces, where water tends to accumulate.

Cementitious waterproofing

They come in the form of a mixture of cement and polymers. They are ideal for areas in direct contact with water, such as swimming pools, basements, or tanks.

Asphalt waterproofing

They are made from bitumen or asphalt and are sold in both sheet and liquid forms. They withstand temperature changes well and are perfect for waterproofing a roof.

Polyurethane waterproofing

These are applied in liquid form and create a continuous, flexible, seamless layer. They have excellent adhesion and are very effective on terraces or roofs exposed to a lot of sun and rain.

Waterproofing for wood

Wood requires specific care, especially outdoors. If you're wondering how to waterproof wood, there are oils, varnishes, and coatings that not only repel water but also nourish and protect the material so it lasts longer without cracking.

Where waterproofing is applied

Waterproofing coatings aren't just used on roofs or terraces. Part of understanding what a waterproofing coating is is knowing which surfaces it can be safely applied to.

• Exterior walls : These are the ones that suffer the most over time.
  
  
• Terraces and roofs : to protect the surface from water and leaks.
  
  
• Roofs and ceilings : the most important thing is to choose products with good adhesion and elasticity.
  
  
• Swimming pools : Swimming pools require specific products; not just any product will do.
  
  
• Wood : Wood is very sensitive to moisture and, without protection, can warp or crack.

How a waterproofing agent works

The most interesting part of learning what a waterproofing product is is learning how it works when applied. Its operation is simple but very effective. It creates a protective layer, visible or invisible, that prevents water from seeping in. Some products form a surface film, while others penetrate the material, sealing the pores from within.

The result is a surface that is more resistant to water, mold, and wear. And the best part is that, with basic maintenance, this protection can last for years.

What is the best waterproofing for exterior walls?

Choosing the best waterproofing for exterior walls can make the difference between having a flawless facade or ending up with damp patches and peeling paint every winter.

Before choosing a waterproofing product

Before deciding on the best waterproofing for exterior walls, there are a few key aspects to consider.

• The type of wall material : Waterproofing brick is not the same as waterproofing concrete or stone. Each has its own unique needs.
  
  
• The climate of the area : If it rains a lot or is constantly humid, a more durable and elastic waterproofing product is recommended. In very sunny areas, one with UV protection is better.
  
  
• The desired finish : There are transparent products that maintain the wall's original appearance, and others that cover it completely, adding color or shine.
  
  
• The Application : Some are applied with a brush or roller, and others with a spray gun. If you want something simple, liquid waterproofers are the most practical.

Types of waterproofing for exterior walls

Knowing what a waterproofing product is helps you understand why there are so many options. Not all of them work the same way or serve the same purpose.

• Acrylic waterproofing : These are the most common and easiest to apply. They form an elastic layer that prevents leaks and adapts to the wall's movements.
  
  
• Siloxane or water-repellent waterproofing agents : These are transparent and penetrate the material without altering its appearance. They are ideal for exposed brick, natural stone, or cement.
  
  
• Polyurethane waterproofing : They are highly resistant to sun, rain, and temperature changes. They are usually applied in liquid form and create a continuous, seamless layer.
  
  
• Cementitious waterproofing: Although they are primarily used in swimming pools or basements, they also work well on concrete walls that are in contact with the ground or moisture.

How to apply waterproofing to exterior walls

Once you've chosen the best waterproofing for exterior walls, the most important thing is to apply it correctly.

Prepare the surface

• Clean the wall thoroughly: remove dust, mold, paint residue or grease.
  
  
• Repair cracks or joints before applying the product.
  
  
• Make sure the surface is dry; moisture prevents the waterproofing from adhering well.

Apply the product

• Spread a layer of sealant if the wall is very porous.
  
  
• Apply the waterproofing product with a brush or roller in crisscross strokes to cover all the pores.
  
  
• Let dry according to the manufacturer's instructions and apply a second coat if necessary.

Review and maintain

Although waterproofing products typically last for years, it's a good idea to check your walls from time to time, especially after heavy rains. A quick checkup can prevent major leaks.

How to waterproof a terrace step by step

Knowing how to properly waterproof a terrace is one of those tasks that can save you a lot of headaches in the long run. Terraces are constantly exposed to the sun, rain, and temperature changes, so it's normal for cracks, leaks, or moisture stains to appear over time.

Prepare the terrace before waterproofing

Before applying the waterproofing product or thermal and acoustic insulation, the surface must be prepared. Poor preparation can cause the waterproofing to adhere poorly or peel off quickly, so this step is essential.

Cleaning and checking the condition of the terrace

• Sweep and clean the entire surface thoroughly to remove dust, leaves, and dirt.
  
  
• If there are any traces of paint or old products, remove them with a spatula or brush.
  
  
• Check for cracks or open joints and repair them with putty or mortar.
  
  
• Make sure the terrace has a good slope so that water does not remain stagnant.
  
  
• Let the surface dry completely

Choosing how to waterproof a terrace

When deciding what to use to waterproof a terrace, you must consider the type of surface (cement, tile, stone, etc.) and its exposure to sun and rain. Not all products work the same, and choosing the right one guarantees a better result.

The most commonly used waterproofing materials for terraces are acrylic, polyurethane, cementitious, and liquid rubber or elastomeric.

How to apply waterproofing step by step

On very porous or old surfaces, it's a good idea to apply a primer before applying the waterproofing. This improves adhesion and prevents the product from being absorbed too quickly.

Apply the waterproofing

• Stir the product well before use.
  
  
• Apply the first coat with a roller or brush, always in the same direction.
  
  
• Let it dry completely (check the manufacturer's time).
  
  
• Apply a second layer crossed over the first, to cover all the pores well.
  
  
• In the most exposed areas, you can apply a third layer of reinforcement.

Let it dry and protect

During drying, avoid walking on the surface and make sure it's not raining. On large terraces, placing a reinforcing mesh between layers improves the strength and durability of the waterproofing.

How to waterproof a roof without mistakes

Learning how to properly waterproof a roof is one of the most important tasks in any home. The roof is the first barrier against rain, sun, wind, and temperature changes, and if it's not properly protected, leaks can end up affecting the entire structure.

Types of roofs and how to protect each one

Not all roofs are the same. Before starting waterproofing, it's important to be clear about the type of surface you're going to treat, as this will determine what you can use to waterproof a roof and what technique you'll use.

Sloped roofs

These are the most common types of sloping roofs in private homes, usually covered with ceramic or slate tiles. In these cases, water easily slides off, but problems often arise in the joints or in displaced tiles.

The key to waterproofing to achieve complete protection is to apply paint or liquid waterproofing over the entire surface, paying special attention to the joint areas.

Flat roofs or walkable roofs

The challenge here is different, as water can easily accumulate. The technique is similar to "how to waterproof a terrace," and the important thing is to choose the right waterproofing material for a terrace or the roof itself.

The most recommended products are those made of polyurethane or liquid rubber, which form a continuous, elastic layer that perfectly withstands rain and sun.

Metal or sheet metal roofs

They are widely used in industrial warehouses and light construction, although they can also be found in some homes. Their main enemy is corrosion. To protect them, it's best to apply an acrylic or polyurethane waterproofing compound that adheres well to the metal and prevents rust from forming.

How to waterproof a roof step by step

Once you've identified the type of roof, it's time to get to work.

Choosing the right waterproofing

Knowing what waterproofing is helps you understand that not all waterproofing products work the same. Choosing the most suitable one for your roof type is essential:

• Acrylics : easy to apply, ideal for tile or cement roofs. They allow the material to breathe and prevent condensation.
  
  
• Made of polyurethane : resistant to standing water and sunlight. Perfect for flat roofs or terraces.
  
  
• Asphalt : in sheet or liquid form, they are durable and very effective against heavy rain.
  
  
• Liquid rubber : They adapt to any surface and create a seamless, continuous layer. They're a great option if you're looking for a durable and flexible solution.

Cleaning and preparation

• Remove leaves, dust or dirt.
  
  
• Repair any cracks or open joints with putty or sealant.
  
  
• Make sure the surface is completely dry before applying the product.
  
  
• Product application
  
  
• Apply a primer if the roof is porous.
  
  
• Apply a first coat of waterproofing with a roller or brush, covering the entire surface well.
  
  
• Let it dry for the time indicated by the manufacturer.
  
  
• Apply a second layer crossed over the previous one to ensure complete coverage.
  
  
• Reinforce the most delicate areas (chimneys, gutters, skylights, or joints) with an extra layer or reinforcing mesh.

How to waterproof roofs with special characteristics

There are roofs that require a little more attention and special tools and equipment :

• With skylights or roof windows : Make sure to seal the edges well before applying the waterproofing.
  
  
• With solar panels : apply the product without covering the anchors or metal fixing points.
  
  
• In very humid areas : combine the waterproofing product with a moisture-resistant paint to reinforce protection.

How to waterproof exterior wood

Knowing how to waterproof wood is essential if you want to keep it beautiful and in good condition for many years. Wood is a natural material that adds warmth and style to any space, but it's also delicate: if not properly protected, sun, rain, or moisture can cause it to crack, discolor, or even rot over time.

Types of waterproofing for wood

Not all products are the same. When deciding how to waterproof wood, you need to consider whether it's used indoors or outdoors, the type of exposure it will receive, and the desired finish.

Natural protective oils

Oils (such as teak, linseed, or tung) are a popular choice because they nourish the wood from within. They penetrate the pores and make it more water-resistant, while enhancing its natural color. They're perfect for flooring or garden or outdoor furniture , although they require periodic maintenance, as their effect fades over time.

Marine or water-based varnishes

Marine varnishes create a protective film that's resistant to sun, rain, and salt water. They're ideal for doors, windows, or outdoor structures. If you're looking for a more discreet, low-gloss finish, water-based varnishes are a good alternative, as well as being more sustainable and easier to apply.

Polyurethane waterproofing

If you're looking for strong, long-lasting protection, polyurethane waterproofing is a safe bet. They form a highly elastic and resistant layer that prevents water from penetrating. This type of product is also used in other projects, such as waterproofing a terrace or even a roof, as they offer great versatility and durability.

Stains with UV protection

Stains are another very effective option, especially for exteriors. Unlike varnish, they allow the wood to breathe and won't crack over time. In addition, many include UV filters that protect against the sun without altering the natural tone of the material. They are ideal for fences, pergolas, or siding.

How to waterproof wood step by step

Once you've chosen the product, it's time to apply it properly. Knowing how to waterproof properly is what guarantees a long-lasting result.

Prepare the surface

• Sand the wood gently to open the pores and remove old paint or varnish residue.
  
  
• Wipe off any dust and make sure it's completely dry before you begin.

Apply the waterproofing

• Stir the product until it is homogeneous.
  
  
• Apply the first coat with a brush, following the direction of the grain.
  
  
• Let it dry for the recommended time and apply a second coat to reinforce the protection.
  
  
• If the wood is heavily exposed to sun or rain, add a third coat for added strength.

How to waterproof a pool step by step

Knowing how to properly waterproof a pool is essential to prevent leaks, seepage, and moisture problems that, over time, can damage the structure. Always remember to use specific pool products .

What to consider before waterproofing a pool

Waterproofing a pool requires more than just applying a product and waiting for it to dry. Several factors must be considered that will directly influence the result:

• The pool material : A concrete or tile pool is not the same as a prefabricated one. Each type requires a different waterproofing agent.
  
  
• The condition of the surface : If there are cracks, open joints or areas with moisture, they must first be repaired.
  
  
• Sun and weather exposure : In outdoor pools, sun and temperature changes can affect the product's durability.

Types of waterproofing most used in swimming pools

When deciding how to waterproof a pool, the most important thing is to use products specifically designed to withstand pressure and continuous contact with water.

Cementitious waterproofing

These are the most common coatings for concrete or built-in pools. They are easily applied with a brush or roller, creating a sealing layer that prevents leaks. They also allow coatings such as mosaic tiles or mosaic tiles to be placed on top without losing adhesion.

Liquid polyurethane or acrylic membranes

These form a continuous, flexible film that adapts perfectly to any shape or corner. They resist moisture and structural movement well. In fact, this type of product is also used to waterproof a terrace or a roof, as it offers long-lasting protection.

Epoxy resins

Although they tend to be more expensive, epoxy resins are one of the most durable options. They create a smooth, waterproof, and glossy surface, ideal if you're looking for a decorative finish without needing to reline the pool.

PVC tarpaulins or sheets

For prefabricated or deteriorated pools, PVC liner is a practical alternative. It acts as a waterproof lining that prevents leaks and is quick to install, requiring no construction work.

How to waterproof a pool step by step

Good preparation is half the battle. If you want your waterproofing to last and work, you need to follow a few basic steps.

Prepare the surface

• Thoroughly cleans the entire pool, removing any paint, mold, or grease.
  
  
• Repair cracks with special mortar or suitable sealant.
  
  
• If the pool is new, make sure the concrete is completely dry before applying anything.

Apply the waterproofing

• If indicated by the manufacturer, apply a coat of primer to improve adhesion.
  
  
• Spread the first layer of waterproofing with a brush, roller or trowel.
  
  
• Let it dry for the recommended time and apply a second coat in a crisscross pattern.
  
  
• Pay special attention to corners, joints, and areas where leaks often occur.

Place the final coating

Once the waterproofing is completely dry, you can apply the chosen finish: mosaic tile, special paint, or epoxy coating. Each material has its own curing time, so it's best to follow the manufacturer's instructions.

Professional recommendations for a long-lasting finish

Learning about waterproofing isn't just about knowing what the product is and how to apply it; it's also about knowing how to achieve results that last for years without deteriorating.

• Don't skimp on quantity : applying the product generously and evenly ensures complete coverage.
  
  
• Respect drying times : each layer takes time to harden. Don't skip steps or step on the surface before the drying time.
  
  
• Apply under suitable conditions : avoid rainy days, high humidity, or extreme temperatures. Ideally, work in a temperate, dry climate.
  
  
• Regular maintenance: Check the surface once a year and apply a new coat if worn or porous areas are detected.

What is the best time to waterproof each surface?

Choosing the right time to apply a waterproofing product is almost as important as knowing what a waterproofing product is or how to apply it properly. Therefore, planning the right time for each surface is key to ensuring a perfect, long-lasting job.

Exterior walls

Ideally, this should be done in spring or early fall, when temperatures are mild and the environment is not too humid. In winter, cold and rain can affect drying, and in midsummer, extreme heat can cause the product to crack or lose its adhesion.

Terraces and roofs

Whether you're thinking about waterproofing a terrace or a roof, it's best to do it before the rainy season. Spring or late summer are perfect: the weather is good, the product dries well, and the surface is ready to withstand the fall and winter. If using a polyurethane or resin waterproofer, it's best to avoid very hot days, as it could dry too quickly.

Interior ceilings

The climate doesn't play as much of a role if the roof is covered indoors, but it's important that the area is well-ventilated and dry. If the roof is covered outdoors, follow the same recommendations as for a roof: dry weather, moderate temperatures, and no rain in the days following application.

Exterior wood

Spring is usually the best time. The temperature is mild, and the air isn't as humid as in winter. Plus, if you do it on dry days, the product penetrates the wood pores better and provides longer protection.

Swimming pools

When it comes to waterproofing a pool, it's best to do it before summer, meaning between late spring and the beginning of the hot season.

Conclusion

Ultimately, understanding what a waterproofing product is and how to waterproof each surface is the foundation for preventing leaks, dampness, and drips for years to come.

Knowing which is the best waterproofing for exterior walls, how to waterproof a terrace, or even how to waterproof a roof can seem complicated at first, but with the right information and the right products, the results are worth it.

Preparing the surface well, applying the product carefully, and doing so at the right time of year will make the difference between long-lasting protection and a temporary fix.

Waterproof with Brikum

At Brikum, we're clear: a good result starts with a good product. In our online store, you'll find the best building materials for renovating your home and repairing any damage. Not just in your house, but also in your garden or pool.

We work with acrylic, cementitious, polyurethane, and asphalt waterproofing materials , designed to offer maximum protection against water, sun, and humidity.

We'll also help you choose what to use to waterproof a roof, how to waterproof a terrace, and which waterproofing product is best for exterior walls, depending on your needs. Visit Brikum, choose the product that best suits your project, and say goodbye to damp and leaks forever.