How to Waterproof the Balcony Floor?: Wood and Concrete

Written By Adam Paul - Waterproofing Expert

The balcony floor can be waterproof by following the below step-by-step guide. You should have suitable tools and instruments before starting balcony waterproofing. Most of the balconies are made of wood and concrete. Hence you can waterproof both wood and concrete balcony decks using below tools, instruments, and guide.

7 Steps for Balcony Floor Waterproofing

1. Clean the balcony floor
2. Repair damages on the balcony floor
3. Seal the balcony floor joints and edges
4. Apply primers on the balcony floor
5. Apply a waterproof membrane on the balcony floor
6. Let the balcony waterproofing dry
7. Check for the balcony waterproofing leaking

You can use both liquid and sheet waterproofing membranes for balcony waterproofing. For wood balconies, you can use sheet membranes, while for concrete balconies, you can use both.

If you do not waterproof the balcony properly, you can see these negative impacts such as stain marks, dampness, mold and mildew on the walls, wall paint peeling, wall material deterioration, rot and decay materials, insect damage, reduced structural damages and aesthetic view with increasing the maintenance cost of the balcony.

When you waterproof the balcony, you should waterproof the balcony walls, doors, and windows properly. You should always have expert knowledge before choosing balcony waterproof products and conducting your DIY balcony waterproofing project.

How to Waterproof the Balcony Floor?

These are the 8 steps for balcony waterproofing

1. Clean the balcony floor
2. Repair damages on the balcony floor
3. Seal the balcony floor joints and edges
4. Apply primers on the balcony floor
5. Apply a waterproof membrane on the balcony floor
6. Let the balcony floor waterproofing dry
7. Check for the balcony waterproofing leaking

1. Clean the Balcony Floor

Before applying the waterproofing membrane on the balcony floor, you should clean it. Concrete and wood balconies are the most available balconies. Hence you should clean concrete and wood balconies by following the steps.

Before cleaning the balcony floor, you should remove tiles, top layers, and floorings that you have installed for better waterproofing performance. This depends on your waterproofing budget, time, requirements, and water damage percentage.

Newly constructed outdoor concrete balconies can be cleaned as below, and the old tiled balcony deck should be cleaned with removing tiles. If you do not wish to remove tiles, you can use a balcony deck sealant, coating, and crack fixing method for the waterproofing.

Wood exterior balcony floors should be cleaned by removing rotted, decayed and deteriorated wood parts and then repairing the deck before following the below cleaning method.

Steps to Clean Concrete Balcony Floor

1. Sweep the concrete balcony floor - First, you should sweep the concrete balcony floor using a stiff-bristled broom. This will help to remove loose dirt, dust, and debris on the surface.
2. Wash the concrete balcony floor using a power washer - You should use a power washer to wash the balcony floor to remove dirt, mold, mildew, and loose particles. Power washing is the most effective way to clean a concrete balcony floor. 
3.  Use a concrete cleaner - Before you waterproof you should clean the concrete using a concrete cleaner. You can use CC501 Heavy Duty Concrete Cleaner and Triple Crown Concrete Cleaner as commercial cleaners. As well as you can use a homemade solution (like vinegar and water) to treat any stubborn stains. Apply the cleaner to the surface and scrub using a stiff-bristled brush. 
4. Rinse the concrete balcony floor - After the cleaner is applied, you should rinse the floor with clean water using a garden hose or another round of power washing. 
5. Dry the concrete balcony floor - After the cleaning process, you should Allow the balcony floor to dry completely before applying any waterproofing products. 

6 Steps to Clean Wood Balcony Floor

1. Sweep the wood balcony floor - After the structure repair, you should sweep the outdoor balcony floor using a broom to sweep off any loose dirt or debris.
2. Use a wood cleaner for balcony woods - You should use a wood cleaner to remove dirt, mildew, and algae.
3. Scrubbing the wood balcony deck - You can use a scrub brush or a soft cloth to scrub the cleaner into the wood. During scrubbing, you should identify the cracks and damages on the balcony deck wood. 
4. Wash the wood balcony floor using a power washer - If you are not able to remove any dirt, mold, and mildew that are strictly sticks to the wood surface, you can use a pressure washer to remove those easily.
5. Rinse the wood deck surface - After the pressure washing the balcony deck, you should rinse the cleaner off with a garden hose. 
6. Dry the balcony wood deck - After washing, you should allow the balcony to dry completely. This may take a day or two, depending on the weather.

2. Repair Damages on the Balcony Floor

After cleaning the balcony floor, you should repair the damage on the balcony floor. Balcony floor damage repairing is a combined process of sealant filling, dealing, and drying. You should use a suitable crack filling for the concrete balcony deck damages, and you will need a wood filler for the wood balcony floors. 

Repair Damages on the Concrete Balcony Floor

1. Create a dovetail groove in the area of the crack - You should create a dovetail groove in the area of the crack or damage on the concrete balcony surface. This groove shape helps the repair material to stay in place.
2. Filling the dovetail grooves using a filler - You should fill the grooved lines on the outside concrete balcony using a recommended filler. You should mix the filler according to the manufacturer's guidelines. After filling the groove lines, you should seal the surface
3. Drying the sealed surface on the concrete balcony deck - You should let the filling to dry. The drying process depends on the manufacturer. So you should carefully read the manufacturer's guidelines while using. Do not let the water on the concrete balcony deck before curing.

Repair Damages on the Wood Balcony Floor

1. Fill the wood cracks and damages on the balcony deck - You should apply the wood filler or epoxy to the damaged area using the putty knife. Make sure to press it into the damage and then smooth it out so that it is level with the surrounding surface.
2. Sand excess filling on the damaging areas on the wood balcony floor - Once the filler or epoxy has dried completely, use sandpaper to smooth the surface. This will ensure that the repaired area blends in with the rest of the floor.
3. Seal the wood balcony floor using a recommended wood sealant - You should apply a wood sealer to the repaired area using a paintbrush. This will protect the repair from moisture and help to prevent future damage.
4. Let the balcony wood deck dry after sealing - Then you should allow the sealer to dry completely before proceeding with any waterproofing. This could take several hours to several days, depending on the product and the extent of the damage.

3. Seal the Balcony Floor Joints and Edges

After the damage and crack repair process on the balcony deck, you should seal the joints and edges using waterproof tape and sealants. In particular, you should waterproof the balcony floor and wall edge to prevent the water from leaking inside the structure. Balcony floor joints and edges should be sealed for both concrete and wood balcony floors. 

You should seal the balcony floor and wall edge at least 6” above the balcony floor in order to prevent balcony water flashing. 

4. Apply Primers on the Balcony Floor

After edges and joint sealing, you should apply primers on both concrete and wood balcony floors. Waterproofing primers increase the adhesiveness between the waterproofing membrane and the balcony floor substrate. You can use a roller brush or paintbrush to apply the primer evenly across the entire surface of the balcony floor. Make sure you cover all areas, including corners and edges.

Once the primer is wet, check for the missing areas on the layer and then reapply the waterproofing primer on the balcony floor. The number of the primer coating depends on the manufacturer's guidelines. 

5. Apply a Waterproof Membrane on the Balcony Floor

You should apply a waterproofing membrane on the balcony floor after the priming process. You can use liquid waterproofing and sheet waterproofing membranes for concrete balcony floors. As well as you use can sheet waterproofing membranes for wood, metal, and composite balcony floors. You should consider these important things while applying waterproofing membranes on concrete and wood balconies.

Important Factors about Liquid Waterproof Membrane for Balcony Floor Waterproofing

1. You can use a liquid waterproofing membrane for concrete balcony floor waterproofing.
2. Choose a UV-resistant liquid waterproofing for outside balconies
3. Apply a recommended coating of liquid waterproofing membrane on the balcony floor
4. Do not exposure the water until the liquid waterproofing is drying on the balcony floor

Important Factors about Sheet Waterproof Membrane for Balcony Floor Waterproofing

1. Use sheet waterproof membrane on the outside wood, metal, and composite balcony waterproofings.
2. Maintain the recommended sheep lap joints for the sheet waterproofing membranes (HDPE, PVC) on exterior balconies. 
3. Maintain the recommended temperature for the torch membranes (bituminous waterproofing membranes)
4. Seal the joints using a recommended tape from the sheet manufacturer 

6. Let the Balcony Floor Waterproofing Dry

The balcony waterproof layer should be let to dry for about 24-48 hours. The drying time of the balcony floor waterproofing depends on the manufacturer's guidelines. Hence, you should always follow the manufacturer's guidelines for higher performance. You should not allow the balcony floor waterproofing layer to be exposed to water during the drying time.

7. Check for the Balcony Waterproofing Leaking

After the waterproofing is dried, you should check it for leaks. Now you can pool the balcony beck areas and check for leaking 24-48 hours. 

What Tools and Instruments Can be Used for Balcony Floor Waterproofing?

You will need specific tools and instruments for balcony floor waterproofing for specific tasks on the balcony deck.

1. Balcony floor cleaning tools - To clean the balcony floor, you should have a broom or brush, a vacuum cleaner, a wire brush, a water hose or pressure washer, and a mild detergent or cleaning solution.
2. Tools for repairing the damages in the balcony floor - To repair damages in the balcony floor, you should have a hammer, chisel, putty knife, sandpaper, wood patching compound or concrete mix, and a trowel. 
3. Balcony floor sealing tools- You should have a concrete sealer or waterproofing agent and acquire a paint roller or sprayer for waterproof sealing (wood sealer) on the balcony floor. 
4. Balcony floor priming tools - You should have a concrete primer or bonding agent and use a paint roller or sprayer to apply a primer on the balcony floor.
5. Tools for waterproof application on the balcony deck - Finally, for applying a waterproof membrane on the balcony floor, you will need waterproofing membrane sheets or rolls, a suitable adhesive or bonding agent, and a paint roller or trowel.

What Waterproof Membranes Can be Used for Balcony Waterproofing?

You can use both liquid and sheet waterproofing membranes for balcony waterproofing. For wood balconies, you can use sheet membranes, while for concrete balconies, you can use both.

You can use these 9 high-quality and recommended waterproofing products for balcony floor waterproofing.

1. Sikaproof A+ - Sikaproof A+ is a highly elastic, durable, waterproof, easy to apply waterproofing membrane for balconies.
2. Mapei Mapelastic - Mapei Mapelastic is a liquid, highly flexible, crack-bridging polyurethane membrane with excellent UV and chemical resistance waterproofing membrane for the balconies.
3. Soprema Felx'o Drain - Soprema Felx'o Drain can be used for pre-attached drainage channels on the underside for efficient water evacuation. It is highly recommended for uneven balcony surfaces.
4. Sikalastic - Sikalastic is a fully bonded and seamless elastomeric waterproofing polyurethane system suitable for parking decks and balcony waterproofing.
5. Triflex BTS-P - Triflex BTS-P is a Polyurethane waterproofing system with excellent adhesion to various substrates, ideal for complex balcony shapes.
6. PCI Peciment - PCI Peciment is a Cementitious waterproofing membrane. It is ideal for balconies with existing tile installations.
7. Nesco Duratex - Nesco Duratex is a modified bitumen membrane with self-adhesive properties, offering rapid application and easy repairs on the balcony waterproofing.
8. Balconyguard Membrane - The Balconyguard membrane is a 60-mil, self-adhesive waterproofing membrane to be used specifically on wood deck balcony structures. It can be used for lightweight concrete also.
9. Gaco - Gaco consists of a series of balcony waterproofing products, including primers, top coat, deck fill, grips, and deck tapes. You can use the Gaco kit that includes all of these balcony waterproofing products.

What if my Balcony is Not Waterproof?

If you do not properly waterproof your balcony, you can observe below 11 negative impacts in your building because the building structure can be damaged due to leaked water heavily. 

The negative impact of not waterproofing the balcony floor

1. Create stain marks beneath the balcony floor
2. Dampness on the walls around the balcony
3. Grow mild and mold around the balcony walls
4. The paint peeling on the balcony walls
5. Material deterioration and loss over time
6. Balcony materials can decay due to UV rays
7. Wood balconies can rot and decay over time
8. Woods can be damaged by insects due to wetting
9. Reduce the balcony's structural strength
10. Reduce the aesthetic view of the balcony
11. Increase the maintenance cost of the balcony

What Balcony Parts you Should Waterproof?

Mainly you should waterproof the balcony floor, walls, door, and windows in the balcony in order to prevent water damage. The most water-damaged balcony area is the balcony deck. Hence balcony deck can be damaged by the water. Balcy walls can be damaged due to the spread of water and the balcony doors and windows can be damaged due to not sealing the rails a

Balcony Wall Waterproofing

Balcony wall waterproofing is the process of applying a waterproof layer or barrier to the walls of a balcony to prevent water penetration into the building. You should waterproof the balcony wall a minimum of 1 foot from the balcony deck. 

 Balcony water can flash and seep into the balcony walls by spreading and deck-wall joint line. This leaked water cause to dampen the balcony walls, grows mold and mildew, peels wall paint and reduces the structural strength of the wall. 

Balcony Doors and Windows Waterproofing

Balcony doors and windows should be waterproof to prevent water leaking from non-sealed joints and connections. You can install weather stripping, install door sweeps, install windowflashing and properly seal the balcony railing to prevent water leaking.

How Does Aqviz help to Waterproof the Balcony?

Aqviz always helps you to waterproof your balcony by choosing the best products, tools and instruments, services, consultations, guidance and solutions for the problems. Before you waterproof your balcony, what to know about balcony waterproofing? Aqviz has a complete guide, including the below thing. That will help you to conduct the balcony waterproofing project easily and confidently.

1. Identify the balcony area
2. Balcony parts you should waterproof
3. Balcony materials you should waterproof
4. Waterproof membranes you can use for balcony waterproofing
5. Optional balcony protections
6. Balcony waterproof damage and protection.