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How To Make Your Balcony Flooring Waterproof

In order to make your balcony flooring waterproof, it needs to be encapsulated by a waterproofing membrane. Just like a flat roof this protects the structural integrity of the substrate below. It also reduces the risk of your balcony and other parts of your property suffering from water damage. Whether you have direct access to the substrate or have tiles covering the floor of your balcony it can be waterproofed. However, this will likely influence which type of balcony waterproofing system you will use.

Choosing A Waterproofing System For Your Balcony Flooring

The condition and use of an existing balcony substrate will dictate the best system to use when coating. For instance, if the existing flooring is coated in mastic asphalt and is badly cracked in places these must be filled in and repaired prior to coating. The reason for this is most coating systems only bridge gaps up to 2mm wide. Preparation is the most important part of any waterproofing system. If the work area is not prepared correctly the waterproof layer will ultimately not be of a required standard. This will result in premature failure. All debris such as loose particles and chippings need to be removed. The area often needs to be jet washed or vigorously scrubbed to remove all grease. A primer may be required. This can be checked by conducting a simple peel test.

Some balcony flooring systems also require a specific primer. Some primers can be slow curing and will have a large impact regarding which waterproof layer will be best for the balcony flooring. The curing time of a waterproof membrane is gauged by the time required to cure by its slowest component. Therefore, a system which does not need a primer, or has a fast-curing primer such as the high performance Mariseal Aqua Primer, is much better suited for use on heavily trafficked balcony areas.

A fast curing waterproofing primer reduces the disruption caused when a new waterproofing system is installed. An example of disruption during waterproofing would include outdoor space being cordoned off for a long period. If the area is frequently used by residents, such as on blocks of flats, a fast-curing system is critical to allow the building to resume normal usage as soon as possible. The disruption caused by undertaking such works amongst often used areas cannot be underestimated. Residents often do not have the patience to wait until a system is fully cured before venturing out onto it. Therefore, a fast curing system is vital in such scenarios.

Overcoating using a hot melt product such as mastic asphalt greatly increases the health and safety requirements of a project. Even more so if the project is in a busy public area. This makes such systems more challenging in built up areas. It is also slower to install compared to modern PU or PMMA liquid systems. These cold applied systems are flame free. Many local authorities would prefer cold applied systems for waterproofing projects. This is especially true for balcony and roofing system refurbishment projects. The reason for authorities preferring cold applied systems is "The Grenfell Tragedy". 

Potential Risks With Waterproofing Projects

Fires during roofing and waterproofing construction started to be discussed as an important issue during the late 1990’s. Approximately 200 roof fires each year are linked to the use of ‘Hot Works’. This number is growing as the amount of construction projects is increasing. Naturally, insurance companies have reacted by increasing their premiums. This has an impact on project delivery costs. CDM (Construction Design Management) regulations now in place attempt to place pressure on specifiers to specify the safest systems. In the coming years this will result in a dramatic reduction of hot works on construction projects.

A further safety consideration which cannot be underestimated is the solvent content contained within any liquid system. It is reasonable to suggest the solvent content of a product has a direct correlation with the odour produced. It is also reasonable to state the solvent content also correlates with the likelihood of a potential flashpoint within the system. This greatly increases fire risk.

Additionally, solvents greatly increase the probability of adverse affects being suffered by people in close proximity. These affects can include nausea and even asthma attacks. thee issues can be be suffered by operatives and building occupants.  Also some PMMA’s are highly inflammable and can cause bad skin irritation.

Those remaining in or around buildings during construction and refurbishment work can be just as affected by the construction chemicals used around them as those using them. Bearing this in mind they must be considered under the CDM Regulations. Designers are required to design and implement an ‘Indoor Air Quality Plan and/or an Outdoor Air Pollution Penetration Policy’

CDM (Construction Design Management) regulations stipulate that many specifiers and building designers must consider information before buildings begin to be constructed to try and eliminate health and safety risks to any person liable to be affected. This means construction chemicals such as liquid roofing systems, adhesives and paints for instance used on site are scrutinised much more. This challenges them to specify the safest materials available.

The intent of this policy is to:

Minimise exposure of workers to risk from pollutants within construction products.

Prevent chemicals contained from collecting in buildings under construction

Prevent air pollution caused by construction materials from travelling into occupied spaces

Exposure to sensitising agents contained in some products can cause irritation and swelling of the air-pathways. It causes symptoms like acute asthma. Sadly, in a small proportion of people the symptoms are not reversible, even once the person is removed from the sensitising product area. So, the chemical content of some liquid systems can vary greatly and needs to be taken very seriously.

Most modern liquids used in construction are

• Moisture triggered - Immediate resistance to rainfall & moisture 

• Tolerant to adverse weather conditions – 0°C to 35+°C

• Highest fire ratings for finished systems: BROOF(t4).

• Stripped of all free monomers – safe to use for both installers and end users.

• UV Stable (some more than others - Aliphatic or Aromatic)

• Fully BBA Certified

So, it is clear to see that there are so many considerations to think about even if a liquid is decided on, as they vary so much considering all the factors previously mentioned.

Asphalt as a system on balconies and walkways - Advantages

• Hard wearing and once installed is a reliable product.

• Superb damp proof qualities.

• Flexible and can move with the building’s expansion and contraction.

• Very long lasting.

Asphalt as a system on balconies and walkways – Disadvantages

• Very labour intensive and involves continuous heavy lifting

• Involves hot works involving very high temperatures often more than 200 degrees Celsius

• Produces a lot of smoke, which is harmless but irritating

• Lots of material required for a typical M2 covering (20mm)

PMMA (Poly methyl methacrylate) as a system on balconies and walkways – Advantages

• Is very durable with a high scratch resistance

• Can be provided in any colour finish

• Is fast curing 30 minutes/45 minutes

• Has a very high impact strength

• Good UV stability

PMMA (Poly methyl methacrylate) as a system on balconies and walkways – Disadvantages

• Very high solvent content with high flashpoint risk.

• Strong odour which can cause nausea and can even provoke asthma attacks

• Very flammable products

• Not good at working in low temperatures

• Can’t be installed in wet conditions

PU Liquid Coating as a system on balconies and walkways – Advantages

• Easy installation method that enables fast coverage rates

• When topcoat has quartz added is very durable with added anti slip qualities

• Not labour intensive and more coverage achievable with less manpower

• When catalyst added a very fast cure time is achievable

• Very cost effective compared to other systems

• Good expansion and contraction qualities

• Good UV stability

• Detailing work is very easy

• Can work well in low temperatures unlike PMMA

• Can be provided in many coloured finishes

PU Coating as a system on balconies and walkways – Disadvantages

• Unless catalyst added can be slower to cure than PMMA

• Some systems have a high solvent content although there are many solvent free systems available such as Mariseal 250W

• Can’t be installed in wet conditions

• Some systems can cause nausea if used in enclosed spaces

The fastest system to install on walkways or balconies is a single part PU liquid waterproofing system. It is relatively straightforward to apply and training courses typically last one or two days. These can take place on or off site and then installers are continuously assessed on subsequent projects. Modern PU waterproofing liquids typically come in two forms. Aromatic chemistry such as TDI (toluenediisocyanate) and MDI (methylene diphenyl diisocyanate) – Aromatic liquids are older chemistry, slightly less UV stable but have enhanced fire retardancy. Aliphatic chemistry such as HMDI hexamethylene diisocyanate and Isophorone diisocyanate (IPDI) have enhanced UV stability but are less fire retardant. There is not a lot of material handling required as typically the system is supplied in buckets and getting the material to the designated work area is relatively easy. This saves much site preparation time as setting up is straightforward.

Typical installation procedure to waterproof balcony with a typical PU Liquid

• Prepare the surface for waterproofing ensuring it is clean and dry

• Undertake a peel test and leave for a minimum of 48 hours to confirm adhesion strength

• Fill any cracks and joints with polyurethane sealant or fast curing compound.

• Apply a layer of primer (type dependant on substrate and if peel test dictates).

• Apply waterproof coating to detail and upstand areas

• Apply a layer of waterproof coating to horizontal area infuse quartz if anti slip required. 

• Apply the finishing layer of waterproof coating.

Need Help With Making Your Balcony Waterproof?

If you would like any further information about making your balcony waterproof,whether it is for a new or existing balcony please contact us or call us now on 01277 375 511. One of our friendly team will be delighted to help make sure you get a waterproof balcony.

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