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Pros & Cons of Waterproofing Membranes for Your Next Project

Waterproofing is one of the most important protective measures to get right for a new construction or renovation. Without the correct waterproofing membrane, water can leak into the foundations, walls, and even ceiling cavities. This can cause rot, mould, cracks and other damage, reducing the lifespan of the construction and leading to costly repairs

Waterproofing membranes prevent this by keeping water and moisture to a limited and expected area, creating an impenetrable layer between what should stay dry and where water is expected (bathrooms, basements, roofs, balconies, etc).

However, waterproofing membranes are not the only waterproofing solution, so what are the pros and cons, and when and when not should they be used?

Pros of Waterproofing Membranes

Waterproofing membranes provide strong protection against water intrusion. They come in a variety of forms, including liquid membranes, sheet membranes, bituminous membranes, and PVC membranes, and while each has its own particular uses and ideal situations, they all provide a barrier against water penetration.

This means that membranes have many versatile applications, with an option for every situation, whether the situation is indoors or outdoors, in the ceiling or underground, or facing regular moisture or just occasional water (like rainfall).

Additionally, many waterproofing membranes are now eco-friendly or have very low amounts of VOCs (volatile organic compounds), which means they are safer for the home and safe for groundwater when exposed to water in the long term.

For both residential and commercial projects, waterproof membranes increase the longevity of the structure by protecting structural elements against rot, corrosion, and weakness from long-term water damage. By preventing mould, mildew and structural damage, the structural integrity is retained, as is the building’s value, all the while saving on expensive repairs for water damage (not to mention downtime).

Cons of Waterproofing Membranes

One of the main drawbacks of high-quality waterproofing membranes is the higher upfront cost compared to cementitious coatings or basic damp-proof membranes, which are usually cheaper but less effective.

Secondly, waterproofing membranes often require professional installation. Without it, some types are prone to failure if improperly applied, which can cause premature water damage.

Finally, some membrane types may need maintenance over time. This can be a moderately expensive task, especially if it requires changing tiles, timber, or if the waterproofing is behind plasterboard.

Project-Specific Waterproofing Needs

Different waterproofing membranes are best used in different situations. The following is a concise list of the best options to use for particular rooms or areas of a construction project.

Bathrooms: Liquid-applied membranes are best as they plug every gap. However, they must be carefully applied to ensure complete coverage of all gaps, seals, and joining spaces.
Balconies / Rooftops: Sheet membranes (e.g. bituminous or PVC) are perfect for deflecting rain or frost moisture from roofs or balconies.
Basements / Below-ground: Self-adhesive or bituminous membranes are best here, as a thick application prevents dampness and ground moisture from seeping into subterranean spaces.
Concrete decks: Flexible liquid membranes provide a comprehensive coating, filling in cracks and any existing damage to create an impenetrable seal.
Green roofs / planter boxes: As plants naturally seek out moisture, look for root-resistant membranes that will stand up to nature’s strength and prevent an errant root from poking a hole in the membrane.

TIP: When choosing the right membrane option for your job, consider other factors, including UV exposure, water pressure, temperature, foot traffic, to make an informed choice.

Comparison Table: Types of Waterproofing Membranes

Common Mistakes to Avoid

There are a number of common mistakes that installers can make when laying down a waterproofing membrane, which can compromise its protective qualities. First, applying to unclean or unprimed surfaces can result in an uneven or damaged seal. Second, using the wrong membrane for the environment can add unnecessary stress to the membrane material, shortening its lifespan.

Next, not following the curing time or thickness guides means either a premature exposure to water and moisture for an unready membrane or a membrane that is too thin to handle the moisture it is exposed to. Finally, skipping reapplication, when needed, results in an ever-weakening membrane that will one day inevitably fail without the proper maintenance.

DIY vs Professional Installation

DIY is feasible in a very few situations, such as applying a liquid membrane in small wet areas. However, we always recommend calling in a professional for more advanced jobs, such as balconies, roofs and ceiling spaces, below-ground spaces, and high-traffic areas, to ensure the most optimal application for your construction or renovation needs.

Choosing the Right Membrane for Your Project

So, which waterproof barrier is the right membrane for your project? Consider the following checklist to narrow your choices:

Interior or exterior: Will the membrane be facing regular water from showers or basins, or incremental water like rain or early morning moisture?
Level of exposure to water/sun: Does the membrane require UV protection or to be thick enough to handle a severe downpour or thunderstorm?
DIY or contractor: Is this a small job that is suitable for a weekend DIY project or do you need to call in a professional and trained contractor for the job?
Substrate type: What kind of material is the waterproofing membrane to be laid on? Different substrates (concrete, tile, wood, etc.) will be better suited for different membrane types.

Still Undecided? Talk to the Waterproofing Experts

The types of waterproofing you choose, whether liquid, PVC or sheet membranes, will depend on your structure or project, but it’s vital to get it right to ensure long-lasting protection against water damage.

While we have gone into the basics for which waterproofing membrane is right for most situations, if you’re still unsure, get in touch with the expert team at Illawarra Industrial Supplies. With extensive experience across a wide range of waterproofing solutions, our team can guide you toward the right option.

Date: 1.09.2025