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Projex - Guide to Waterproofing Commercial Roofs and Balconies

A commercial worksite undergoes a tremendous amount of strain from constant use by many people, and even the strongest of construction elements can show wear and tear over time.

Waterproofing techniques have advanced considerably over the last 50 years, and buildings constructed in the last 20 years are often at risk of their waterproofing giving out. Even if your current solution is holding, it may only be a matter of time before you’re forced to upgrade regardless.

Whether you’re trying to bolster your existing waterproofing or repair faulty or damaged portions, allowing water seepage is an unacceptable risk to the integrity of your building. There are a few key preventative measures and telltale signs that you should never ignore.

Which parts of a building are susceptible to water seepage?

The first thing to understand is the structure of a conventional corporate building, and which parts are most vulnerable to water damage.

  • Roofs, and especially flat roofs without adequate drainage solutions
  • Balconies and terraces
  • Retaining walls
  • Podium decks
  • Planter boxes
  • Basements
  • Lift pits
  • Cellars
  • Expansion joints
  • Water tanks
  • Ponds
  • Fountains

When you’re conducting a check, you should concentrate the majority of your efforts within these areas. That isn’t to say that you should neglect the rest of the areas, or that only these areas can be affected. They’re simply the most at risk.

It’s a good idea while conducting a check of your balcony and roof to have at least a precursory glance at the condition of the others on this list, even if you’re not going to do an entire comprehensive checkup. Leaving one facet unchecked could allow a problem to build up, or even spread further than that one area. There’s no point in having a sealed, watertight and perfect balcony if the room adjacent to it is leaking from the ceiling.

Why does your commercial building need to be absolutely waterproof?

To prevent loss of rent

The last thing you want as a building owner is to have your property uninhabitable due to water leakage, so it’s essential that you have the property waterproofed properly from the start.

For safety reasons for your staff

Water and electricity don’t mix, so if you have wiring that is exposed to leaks due to insufficient waterproofing, there is a very real danger of fire or electrocution. And as the building’s owner, you would be liable for any damages or injuries incurred by your tenants. Mould and mildew caused by water penetration can trigger allergic reactions and respiratory problems in a building’s occupants, and can lead to long-term illness. Bacteria can also thrive in damp areas, and can lead to a building being labelled a ‘sick’ building that then becomes difficult to lease.

For structural reasons

Moisture rots timbers, rusts metal and causes a form of degradation known as concrete cancer. A building that is structurally unsound due to the long term effects of water damage can be a major disaster waiting to happen.

For hygiene reasons

Termites, cockroaches, rats, mice and other pests are attracted to damp areas in a building, which not only poses a health risk for the occupants but also an ongoing cost for the owner, who must bring in exterminators on a regular basis.

Determining a risk or crack

There are three major contributors to wear and tear in commercial buildings.

The first is simply time; even commercial steel is only usually guaranteed rust-free for 25 years, and concrete guaranteed for usually 50 to 60; waterproofing, especially sealants, also have a finite lifespan, and must be reapplied (even if it’s over a span of decades). This is especially true for older buildings that may have had waterproofing at some point, but have simply degraded over the years.

The second is a faulty initial application of waterproofing techniques, which wear over time at a heightened pace or never truly do their assigned job. This represents a potentially extremely hazardous situation, as they may appear to be working and your waterproofing will ostensibly show that it hasn’t reached a time threshold for renewal yet while needing it.

The third is damage, mostly caused by water or unexpected elements, that may precipitate renewal of your waterproofing early.

In order to determine your risk for, or current state of seepage, you should be both looking for signs of pre-existing damage, and telltale signs that your current solution may not last much longer.

Common symptoms and how to remedy them

Most water damage takes the form of some very simple, easy-to-see signs. While some are harder to spot than others, the vast majority can be easily ascertained by following a few simple steps. Some common signs of water damage include the following:

Blistering of felt or plies

Air trapped between the felt, surface plies or beneath the waterproofing membrane itself can warm and rise, causing surface-level blisters. This warmth may be from direct sun contact, the residual rising heat of the floors below, machinery, or any other heat source, and is a sign of potential water damage (or at least trapped moisture, which can lead to water damage).

If left unchecked & the blister ruptures, this water can slip through punctures and negate your waterproofing.

This is usually the case when a building has had substandard waterproofing previously applied. Projex specialises in providing membrane (Wolfin & Cosmofin) solutions for these situations, which can be applied directly over most other waterproofing and existing substrate layers. These membranes allow entrapped moisture in the substrate to dissipate over time as they have water vapour diffusion permeability properties.

Leaking from the floor above

If you’re experiencing leaking, particularly on your balconies or from the floor above you, this may also be a sign of degraded or faulty waterproofing. It’s the most simple solution to see when inside, but on an external or semi-external balcony it can be hard to spot the difference between leaking from roofing and the natural accumulation of rain dripping down from the drainage of the floor above.

Have a look for any water that appears to seep from cracks rather than naturally slide down during precipitation, or any buildup under areas that should be undercover.

This can lead to water damage, mould growth, further cracking in tiles, concrete, and gyprock, and can in extreme cases lead to long-term structural damage.

In some cases (if you’re lucky) you might also own or rent the upstairs portion, otherwise the residents and the building manager must both be informed and their consent reached before you can engage a solution.

Pooling on the roof

Puddles forming on a commercial roof (especially upon vulnerable flat roof structures that may have a harder time draining buildup than those with graded falls) can both easily serve to hasten the degradation of existing waterproofing materials, as well as forming a sign that they may be at breaking point or in fact re-emulsifying.

This leaves you doubly at risk for:

  • Standing water that can deteriorate some membranes after each subsequent bout of rain
  • Water that may find its way into existing cracks and faults more easily.

Physically changing the angle of a roof is prohibitively expensive, and often not a cost-effective solution. The prudent course of action for a commercial building with roof pooling is a combination of applying waterproof membranes to the roof, and improving your overall water drainage. Good building practices state that the quicker water is drained from the surfaces, the less chance of waterproofing issues. Wolfin & Cosmofin membranes can be used where drainage isn’t adequate or in fact water ponds to due to its unique chemical composition, however we still recommend graded falls where possible.

Most membranes won’t tolerate standing water therefore these solutions won’t work unless they are in tandem. More waterproofing will hold for a long time, but adequate drainage will ensure that you get the entire lifetime usage from your membrane, and prevent pooling that doesn’t leak through, but is still a hazard, obstruction, and eyesore.

On top of this, one square foot of water on a flat roof can weigh as much as 5 pounds per inch, which will eventually build up to a large and unnecessary strain if left unchecked.

This can be done with a drainage system, falls to grade, or tiered elevation structures. In some cases and in ideal situations, some companies have been known to use roofs that can accumulate a lot of water to house rooftop gardens.

These have a proven boost for productivity at work and morale in the workplace, necessitating irrigation and water catchment (which, if your roof is pooling, you’re already doing… just without the equipment). They’re also a great way for a company to publicly demonstrate their commitment to preserving the environment.

Roof piping, ventilation, and other piercing objects

An extremely common failure point for moisture and rain damage is where objects penetrate through the substrate or membrane. This can involve piping, a ventilation system for air conditioning (or similar), drains, or any other object that pierces the concrete. Projex Group Membranes are supplied as a total system which incorporates all accessories to allow for detailing of these critical/problem areas as part of the membrane installation.

Sealant rings and other objects that have become degraded can represent a very strong failure point for commercial roofs. This can also translate to outdoor balconies and terraces, where any exterior portions of the floor may also have piercing objects that accumulate either runoff from the floor above, or are struck by precipitation.

Check around the outside of any pipes and vents, or for any cracks within their bodies and also the connection of the membrane to these areas. Seepage can occur even when these are not visible, but obvious discolouration, patchwork grouting, or other obvious signs of wear can be a potential sign of continual water damage.

As well as checking your exterior, you should also follow any piping or venting to the best of your ability, and the best that your floor layout provides, along the pathway. Signs of cracks obscured by concrete may not be visible from the surface, but will inevitably seep down. Puddles and pools around any maintenance areas or places with a large amount of venting may be a sign of water getting through the membrane.

This type of leak is quite insidious, as it may easily spread to the system whose piping is causing the leak. From there, it may wreak havoc within internal systems, or destroy or degrade electronic and mechanical parts.

Preventative checks

Regular checkups are key for preventing a small leak or break from becoming a health hazard. As part of your regular workplace safety list, you should include a thorough checkup of the entire building, fault points and throughout the entire premises, for waterproofing checks.

Try to do a simple check biannually, or whenever you feel that you haven’t for a while. Do a thorough check once per year at absolute minimum.

Use the common failure point list in section 1 to begin your proceedings. Check all facets of each of these areas, testing during rain and the day after rain. Testing at both times is vitally important.

Being able to tell where water is seeping during storms – especially during heavy rain – can be the only time certain cracks may manifest. Even during some lighter showers, there may not be enough water buildup for areas to flood or to let in enough water through a small crack.

The day after, you may see accumulated pools in areas, which tells you immediately that your drainage is insufficient if it’s anything less than a small buildup which will soon leave. As we’ve discussed, even slight buildup that is unchecked will massively degrade some membranes over time, especially if you have an old membrane in place.

Go around to the areas we’ve outlined, as well as any specific areas that your building has which you feel may be at risk. Formulating a preventative plan of action is the only way to guarantee that you foresee issues before they happen.

It’s a lot cheaper to fix an issue that hasn’t formed yet, and doubly so when it comes to waterproofing. As mentioned above, some forms of waterproofing can be placed directly over pre-existing waterproofing that is in disrepair. However, in cases of extreme degradation, you’ll be looking at cracks, structural damage, and other factors which may prevent a ‘quick fix’ to the membrane, and require multiple parties to look at.

For example, a major fault in the construction may be required to be looked at by a certified builder or engineer to check for further structural integrity before you even consider hiring a trained waterproofing fitter.

What to use to waterproof your commercial property

Projex recommends that you always hire a professional contractor for commercial-level waterproofing. In a commercial building, you’re going to want high quality, long term waterproofing solutions, and for that we recommend either Wolfin or Cosmofin membranes, which can only be fitted by a trained, registered professional.

Cosmofin and Wolfin are both environmentally conscious, German-engineered 1.5mm single-layer waterproofing membranes designed for both easy application and maximum protection. They can be applied on surfaces including concrete, timber, steel, CFC, masonry blockwork, and more, and can even be applied over existing, failing waterproofing membranes saving costs on removal of the old & the potential of leaving the structure without any membrane for an extended period of time during this process.

If you’re looking at shoring your pipes and ventilation up due to insufficient pressure on joins causing leakage, especially under high stress conditions, we recommend LinkSeal shoring technology, which is easy fit, adjustable, and can be outfitted by any trained handyman. These do the job of any joining piece, but can be taken off at whim; they’re industrial strength, designed to compete with subterranean or undersea seals under high temperature or stress.

If you’re followed the rules of this guide and are looking for a way to prevent destruction of your company property, or see the telltale signs of problems coming over the horizon, contact Projex on 02 8336 1666 during business hours, or use our online contact form today.

The Projex Mission is to source and supply technically excellent products to meet the needs of owners, designers, insurers and operators of buildings and structures for specialist protection against water, industrial liquids, impact and corrosion risks.