BALCONY WATERPROOFING REPAIRS
Leaking Balconies – Getting It Right – Do It Once
Leaking balconies, roof & rooftop terraces
- Can cause catastrophic damage to structures below.
- Water leaks may cause not only aesthetic
- superficial damage but can progress to affect the structural integrity of the building envelope itself.
- If a failed waterproofing membrane is the reason for the water leaks, then re-grouting or surface sealing is not the way to repair or restore a balcony.
- This is a band-aid method which may stop or slow down water leaks temporarily. However, when the balcony moves, the tiles, grout & membrane will crack & leaks will start again.
- In many cases, when membranes that have failed, the balcony will require a complete stripped off, structural works if needed, waterprooﬁng re-installed & ﬁnish surface.
Items to Consider
- Strength of subﬂoor and screed.
- Presence of substrate dips and hollows.
- Balcony design i.e., correct balcony slope, fall.
- Window / door frame installation.
- Door Threshold sealing.
- Adequate drainage.
- Possibility pipes leaking underneath.
- Existing tiling & expansion joints – if tiling affecting balcony failure i.e., adequate number.
- This is a critical aspect of any waterproofing membrane installation.
- Substrate must be clean of dirt and other contaminants.
- Surfaces prepared, including vacuum cleaning and / or diamond grinding as necessary to leave surface smooth, dry, clean and free of all debris.
- Substrate may need to be washed.
- Before installing a waterprooﬁng system, construction features which represent discontinuity in the membrane layer must be adequately protected & sealed.
- Attachment points for railings, balustrades.
- Joints between horizontal and vertical surfaces.
- Structural and expansion joints. Install sealant 15mm wide to all junctions and tool off smooth.
- Reinforce with polyester or ﬁbreglass mat all upturns to a DFT of 1.2mm 100mm above ﬁnished ﬂoor height or 25mm above water line.
- Make sure membrane system has been installed 200mm onto balcony floor areas.
Door/Window Step Downs
- Install sealant 15 mm wide to all junctions and tool off smooth.
- Reinforce with polyester or 225gsm ﬁberglass mat to all set downs to a DFT of 1.2mm making sure the membrane system has been installed 200mm onto balcony areas.
Drains & Floor Waste Detail
- All ﬂoor wastes shall have a recessed leak control ﬂange installed.
- Prime ﬂange with appropriate primer and allows primer to cure.
- Install membrane system as below and clip ﬂange over membrane when cured.
Drain & Floor Waste Detail
- All floor wastes shall have a recessed leak control flange installed.
- Prime flange with appropriate primer and allows primer to cure.
- Install membrane system as below and clip flange over membrane cured.
Installation method of a class 2/3 waterproof membrane system to external concrete in accordance to A4654.2.
- Waterprooﬁng Systems should not be installed in either hot or cold temperatures i.e under 10°C or over 35°C.
- Surface temperatures will present problems to accelerated and decelerated cure times.
- Waterproofing membrane.
Type of Membrane
- Flexible waterproofing membrane withstand normal cyclic fluctuations.
- Able to withstand ponding water.
- Balcony floors are exposed to direct sunlight and, therefore, to very large temperature variations between day and night-time.
- These variations create formation of strains due to different thermal expansion and contraction of the substrate and finished surface.
- It is critical the tiles and laid with joint sufficiently large to absorb thermal movement.
- Adhesive chosen to bond is fundamental.
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