Balcony Waterproofing: Know these Before Starting

Written By Adam Paul – Waterproofing Expert

Balcony waterproofing is applying a water-impervious membrane on the balcony to prevent water from leaking into the building slab, walls, and structure. You should waterproof the balcony to stop mold growth, metal rusting, paint peeling and cracking, damage to adjoining structures, wood rotting, concrete spalling, and balcony tile damage.

The balcony floor should be waterproofed using a sheet membrane or liquid membrane. You can use waterproof sealant, coating, liquid, and sheet membrane to protect the balcony walls. You can use weather stripping, door sweeps, window flashing, and rail sealing for waterproofing the balcony doors and windows.

Most balconies are constructed with concrete and wood, both of which are impermeable. Hence, both of them should be waterproofed to protect them from water damage. You should follow the below step by step guide below to waterproof the balcony. After waterproofing a balcony, it should be maintained and repaired properly on time to prevent unwanted damages on the layer. So contact Aqviz experts for any balcony waterproofing problem. We are available 24/7.

What is Balcony Waterproofing?

Balcony waterproofing is applying a water-impervious membrane on the balcony to prevent water from leaking into the building slab, walls, and structure. A waterproof balcony can prevent water damage such as structural deterioration, mold growth, and interior water stains, which can all compromise the integrity and safety of the building.

Balconies are mainly 5 types, such as cantilever balconies, stacked balconies, false balconies, stacked balconies, and hung balconies. Among these, cantilever balconies are most susceptible to water damage due to their design, which extends out from the face of the building without any additional support from beneath.

Why Should You Waterproof Your Balcony?

The main reason of balcony waterproofing is to protect it from water leaking.

If a balcony is not waterproofed properly, water can leak into the balcony floor, and the nearest walls, floor, and beams. Prolonged water leaking into the balcony structure causes mold and mildew growth, metal rusting, paint peeling and cracking, damage to adjoining structures, wood rotting, concrete spalling, and balcony tile damage.

To prevent these severe balcony water damages, a balcony should be sealed with a proper waterproofing material. Not only that, you should maintain a proper grading on the balcony floor to direct the water away from the balcony structure.

What are the Balcony Waterproofing Membranes?

Balcony waterproofing membranes are water-impervious layers that can be used to lay on the balcony floor and wall sides to prevent leaks to the balcony floor, walls, and nearest structures.

Balcony waterproofing membranes are mainly of two types: liquid and sheet membranes.

The use of balcony waterproofing membranes mainly depends on the material of the balcony floor. Mainly, balcony floors are constructed with concrete, wood, metal, composite, and plastic.

Recommended waterproofing membranes for specific balcony materials.

• Concrete balcony: Cementitious, Acrylic, Polyurethane (PU), Epoxy, PVC, EPDM, HDPE, Bituminous membrane, SBS modified bitumen, APP modified bitumen, Crystalline waterproofing, Polyurea, TPO membrane, Hybrid polymer membrane
• Wood balcony: Polyurethane (PU), EPDM, Bituminous membrane, SBS modified bitumen, Acrylic elastomeric, Rubberized asphalt, Butyl rubber, Polyurea
• Metal balcony: Polyurethane (PU), Epoxy, Acrylic elastomeric, Silicone coating, Polyurea, Butyl rubber, Rubberized membrane
• Composite balcony: Polyurethane (PU), Acrylic elastomeric, EPDM, PVC membrane, Hybrid polymer membrane, Polyurea
• Plastic balcony: PVC membrane, EPDM, Polyurethane (PU), Silicone coating, Rubberized membrane, Hybrid polymer membrane

Do you need to know more about balcony waterproofing membranes? So read the guide. Aqviz experts have prepared this using their 10+ years of balcony waterproofing experience.

Why Should You Waterproof the Balcony Floor?

You should waterproof the balcony floor to stop water from leaking from the floor area. From our field inspections at Aqviz, more than 65% of balcony water leakage originates directly from the balcony floor surface, not from walls or railings. The main reasons for balcony floor leaking are insufficient gradient (typically less than 1:60 (≈1.7%)), no waterproofing membrane, and poor drainage on the surface, which allows rainwater to pond instead of draining toward the outlet.

You should waterproof the balcony floor because it is the most critical damaged area on the balcony. Concrete deterioration, tile debonding, wood decay, metal corrosion, and crack formation are the most damaging in the balcony floor. To prevent these, you can install both liquid and sheet waterproofing membranes, depending on the balcony floor material.

Why Should You Waterproof the Balcony Walls?

You should waterproof the balcony wall to stop water from penetrating through the exterior wall surfaces. From our field inspections at Aqviz, more than 30% of balcony moisture intrusion occurs through balcony walls due to direct rain exposure and water flashing from the deck surface. The main reasons for balcony wall leakage are unprotected wall surfaces, failed sealants at joints, and poor balcony drainage that allows water to splash and flow toward the walls.

You should waterproof the balcony wall because it is one of the most vulnerable areas for long-term moisture damage. Paint peeling, surface staining, mold growth, mildew formation, material warping, and efflorescence are the most common damages seen on balcony walls. To prevent these issues, you can apply liquid waterproofing membranes on concrete balcony walls and use sheet membranes or waterproof sealants on wood, brick, and composite balcony walls, along with proper balcony drainage to control water flashing onto the walls.

Why Should You Waterproof the Balcony Doors and Windows?

You should waterproof both balcony doors and windows to stop water from leaking into the interior space. From our site inspections at Aqviz, balcony doors and windows are common leakage points due to non-sealed joints, loose frames, and failed connections between the frame and wall. The main reasons for balcony door and window leakage are poor sealing, missing flashing, and improper detailing that allows rainwater to pass through gaps and joints.

You should waterproof balcony doors and windows because water intrusion at these openings leads to interior wall dampness, paint peeling, floor damage, and mold growth near the openings. To prevent these issues, you should install weather stripping around the edges of balcony doors and windows to create a tight seal and block water and air infiltration. You should install door sweeps at the bottom of exterior balcony doors to stop water from seeping underneath. You should install proper window flashing for balcony windows to direct water away from vulnerable junctions. You should also properly seal balcony railings to prevent water from entering the structure and migrating toward door and window frames.

Which Balcony Decks Should You Waterproof?

You should waterproof wood and concrete balcony decks. Wood and concrete are the most used deck materials for the substrate, and both are permeable. Hence, wood and concrete balconies should be waterproofed before installing balcony decking on them.

• Wood Balcony Deck Waterproofing: You should waterproof the wood balcony deckings. Wood is naturally porous and absorbs water, which can cause swelling, warping, rotting, and fungal growth over time. To prevent these damages, you should waterproof the balcony deck before installation or maintenance. You can use liquid waterproofing membranes such as polyurethane (PU), acrylic, and polyurea, or sheet membranes such as EPDM, PVC, and rubberized membranes to protect the wood decking from water penetration.
• Concrete Balcony Deck Waterproofing: You should waterproof the concrete balcony deckings. Concrete is porous and can absorb water, leading to cracks, rebar corrosion, efflorescence, and surface deterioration over time. To prevent these damages, you should waterproof the balcony deck during construction or before tiling. You can use liquid waterproofing membranes such as polyurethane (PU), acrylic, epoxy, and polyurea, or sheet membranes such as PVC, EPDM, HDPE, and bituminous membranes to protect the concrete decking from water ingress.

How to Waterproof a Balcony?

You can waterproof the balcony floor by using the step-by-step guide. Balcony waterproofing requires expert knowledge, tools, materials, and instructions. Therefore, you should know how to waterproof a balcony? Properly step by step with recommended tools, materials, and instructions. But this quick step guide helps you to understand the process of balcony waterproofing.

Waterproofing a balcony in 7 steps

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 waterproof membranes on the balcony floor
6. Let the balcony waterproofing dry
7. Check for balcony waterproofing leaking

What are the Waterproof Balcony Floorings?

Waterproof balcony flooring is a type of flooring designed to prevent water infiltration, leakage, or seepage into the balcony deck. Waterproof balcony floorings are made from water-resistant materials that can be used in outdoor spaces such as balconies, patios, and decks. They are designed to withstand harsh weather conditions, including heavy rain and snow, and are also easy to clean and maintain.

The most popular 8 waterproof balcony floorings are

1. Rubber balcony flooring
2. Vinyl balcony flooring
3. Epoxy Coating
4. Wooden Deck Tiles
5. Artificial Grass
6. Composite Decking
7. Ceramic Tiles
8. Porcelain Tiles

4 Importance of waterproof floorings.

1. Act as a waterproof flooring as a barrier against water
2. Waterproof flooring prevents water from seeping through the floor
3. Waterproof flooring helps to create a slight slope to facilitate water drainage
4. Waterproof floorings have a sealed surface that prevents water absorption

How to Protect the Balcony Waterproofing Layer?

You can protect the balcony waterproofing layer by following the 8 methods.

1. Apply weatherproof coating on the balcony walls and floor
2. Do regular balcony maintenance
3. Apply UV-resistant coating on the balcony deck and walls
4. Prevent using harsh chemicals for balcony cleaning
5. Choose the right waterproofing products for your balcony: Choose a balcony waterproofing product. These products are specifically designed to provide a waterproof barrier and protect the waterproofing layer on the balcony.
6. Apply a balcony floor coating: Balcony floor coating not only enhances the appearance of your balcony but also provides an extra layer of protection against water and other elements.
7. Build a balcony drainage: If your balcony is highly impacted by water, you should build a drainage to remove the excess water on the deck.

How to Damage a Waterproof Layer on the Balcony?

The waterproofing layer on the balcony can be damaged due to physical impacts, incorrect installation, wear and tear of membranes, poor waterproof installation, exposure to UV rays, exposure to harsh chemicals, and incorrect repairs.

The most common waterproof damage in the balconies is cracks, punctures, wear, tearing, and peeling. These damages cause water penetration beneath the balcony deck and grow mold and mildew, form stain marks, rot the balcony materials, produce bad odors, and deteriorate the structure over time.

The negative impacts of the waterproof layer damaging the balcony are increasing cost of maintenance and repairs, decreased lifespan, increased health risk, decreased aesthetic appeal, and reduced property values.

Should You Waterproof a Composite Balcony?

Composite balconies should be waterproof to prevent mold and mildew growth on the outdoor balcony deck. Composite balconies are made of wood-plastic composites (WPC). When the WPC gets wet, it can tend to mold and mildew growth. This can make the slippery and unsafe deck surface. Therefore, you should apply a waterproof coating or sealant on the composite balcony floor in order to prevent water damage and UV ray damage.

Should You Waterproof the Tiled Balcony?

You should waterproof the tiled balcony deckings. Tiles and grouts are not waterproof, hence water can leak from the spaces and gaps between tile connections even if it is grouted. To prevent water leaks and damages you should waterproof the balcony deck before tiling. You can use liquid waterproofing membranes such as polyurethane (PU), acrylic, epoxy, and polyurea, or sheet waterproofing membranes such as PVC, EPDM, and HDPE beneath the tile system.

Can I Tile over the Waterproof Balcony?

You can tile over the waterproof balcony. Before you tile the balcony floor, you should waterproof it because water can leak through the grout lines because tiles are not waterproof materials. Hence, water can leak through the balcony floor and damage the structure.

Should You Waterproof Patios?

Yes, you should waterproof patios. Waterproofing patios is generally advisable because it helps protect the material from water damage, prevents mold and mildew growth, and extends the life of the patio. This is especially important for porous materials like concrete and natural stone, which can crack and erode over time due to water infiltration.

What is Aqviz’s Thought About Balcony Waterproofing?

Balcony waterproofing is a combined process of balcony floor waterproofing, wall, door, and window waterproofing. You should waterproof all types of exterior balconies that are made of concrete, wood, metal, plastic, and composite materials. You can use liquid and sheet waterproofing for the concrete balcony waterproofing and sheet waterproofing for wood, metal, and composite materials.

You should apply a waterproof coating or sealant on the PVC balconies to prevent mold and mildew that cause it to become slippery. When you waterproof the balcony, you should know how to waterproof the balcony properly. The Aqviz team is always here to help you.