A bathroom is a place that we all take for granted until it’s not there. Waterproofing Bathroom services can make sure you never have to worry about flooding or any leaks in your home, with experts in installation of waterproofing materials.

How to stop bathroom or shower leakage without removing tiles?

Le Fong is a specialist in the non-destructive repair of leaking showers.

Our ISO accredited sealing system is applied both over and underneath leaking tiles – targeting the underlying waterproof membrane to produce a full seal. This process is performed without removing or damaging your bathroom tiles or shower fittings.

All of our sealants are resistant to mould and wear and are available in a variety of colours to suit your waterproofing bathroom decor. Our standard service is more cost-effective than a ’tiles removed’ solution.

We stand by the quality of our repairs and product warranty.

Our Standard Service

1. Leakage Issues Check
   Using a non-invasive electronic leak detector and thermal imaging camera, our consultant will accurately diagnose leaky tiles or pipes in your toilet.
2. De-grout
   De-grout (to a required depth) of the shower perimeter, floor waste, wall-to-wall junctions and hob joints is one of the methods that we have for bathroom waterproofing.
3. Repair the membrane
   Our liquid waterproofing membrane is injected underneath the floor tiles to repair the faulty waterproofing.
4. Re-grout floor and joints
   The grout is then replaced with our exclusive epoxies. A sealant is also applied to the shower floor for waterproofing bathroom.
5. Reseal shower walls
   A penetrative sealant is then applied to the wall grout of the shower cubicle. The service is complete at this point – having taken only 3-4 hours. The shower is ready to use the next day.

Complete Floor Tiles Repair Service

In some circumstances – whether due to customer preference or the extent of the damage – the ‘no tiles removed’ service may not be the most appropriate waterproofing system solution.

In these cases, we can offer a complete and fully licensed shower waterproofing and tiling service to increase your property value.

Service all tiled areas of your home: shower, bathroom, kitchen, or balcony.

Your tiled area is as-new.

No demolition tile-over-tile service

Need to re-tile on a budget? We offer a fast, convenient, no demolition tile-over-tile service or no structural damage process.

If necessary, a repair of the waterproof membrane can be carried out before the new layer of shower tiles is laid.

Enjoy the benefits of a re-tile renovation – for less!

1. Get A Free Shower Health Check

We carry out an advanced leak detection test to locate the source of the problem. Your free report enables you to make informed choices, and compare repairers. If you need a plumber we’ll tell you.

2. Get A Free Quote (with options)

Your on the spot quote will always include options where relevant so you’ll never pay for repairs you don’t need or can’t afford.

3. Get Everything Explained To You

Expect honest, clear, explanations of every problem we assess so you know exactly what’s wrong, how it will be fixed and why it will be fixed that way.

4. Get An Appointment Time That Suits You

We’re really flexible. We can come to your place outside of business hours and we won’t charge extra for it!

5. Get Excited!

Your shower is about to be back to its best and ready to use the day after work has been performed. All without removing any tiles! No unhealthy smells and mess left behind when the work is completed.

Free Shower Health Check Includes:

Plumbing Pressure Test

A leak, recurring mould growth, failing seals or damaged grout could mean a plumbing or shower recess waterproofing problem. A pressure gauge device clearly indicates if water pressure to the shower is satisfactory. Low pressure readings are a strong indication that a plumbing problem exists.

Moisture Detection With Cutting Edge Equipment

Thermal imaging technology and moisture measuring devices allow us to accurately measure build-up of water behind tiles, in shower walls and floors etc. Moisture Meter gauge and infrared camera devices are used to detect leaks and clarify the severity of the problem.

Inspect All Grout Joints Manually

Cracked, damaged or missing grout indicates an underlying problem. This is common in old showers or where long-term water penetration has caused damage. The grout’s condition, quality and depth, are inspected and the technician can restore it to a fully waterproofed condition if required.

Assess Structure & Adhesion Of All Tiles

Dislodged, loose or cracked tiles are a strong indication of water build-up behind the walls and floor. Loose tiles can be a sign of aged or failing adhesive. Leak detection devices and the technician’s experience are used to determine the cause. Several stages of deterioration will inevitably follow if the problem isn’t fixed.

Flood-Test Recess

Filling the shower recess with water and monitoring penetration points assists technicians with identifying any additional leak points, that may not have been highlighted in the previous 4 steps of the Leak Detection process. Water penetrating during a flood test often highlights unknown, or potential future problems outside the shower, such as water damage to the bathroom floor, adjacent rooms, carpets etc.

Prefabricated Bathroom / Toilet Unit

Source: Building and Construction Authority

The bathroom is an indispensable component in all buildings. The conventional method of constructing a bathroom on-site involves many labour intensive building trades such as brick or blockwork, waterproofing, finishes, plumbing, sanitary, electrical works and accessories installation. This requires extensive manpower, time and coordination among trades within a restricted site environment.

A prefabricated bathroom unit (PBU) refers to a bathroom unit pre-assembled off-site complete with finishes, sanitary wares, concealed pipes, conduits, ceiling and bathroom cabinets before installation into position. A PBU which integrates various trades and is constructed in an off-site factory environment can achieve consistent and high-quality workmanship and improved site productivity.

The introduction of PBU can address the extensive on-site manpower, time, and coordination issues. Off-site fabrication can run parallel to other construction site activities, thereby shortening the construction cycle. The effects of inclement weather downtime are also minimized. Other benefits of PBU include better control of materials, streamlined factory fabrication and production processes, less co-ordination with multiple trades/parties, less abortive work for construction sites, etc.

PBUs have been widely used around the world including Japan, USA, UK, Italy and many other countries. There are many types and variants of PBU in the market. In Singapore, both HDB and private developers have used PBUs in some projects since the mid-90s.

This edition focuses on Precast Concrete Volumetric System PBU i.e. PBU with concrete floor and walls, for residential developments. The other types of PBUs will be covered in subsequent publications.

Types of PBU

• Wall & Floor Concrete
• Wall: Drywall panels | Floor: Concrete
• Wall: Lightweight Concrete | Floor: Concrete
• Wall: Steel Panel | Floor: Panel
• Wall: Ferrocement | Floor: Concrete
• Wall & Floor: Fibre-reinforced panel (FRP)

There are many types of PBU and it is essential to understand the characteristics of each type before its selection for use. The above pictures show 2 main types viz. PBU formed with a concrete base and walls of concrete or other materials e.g. drywall, steel panel, etc. and PBU with fibre reinforced walls and floor panels. Each type has its own characteristics. Developers, consultants and builders should evaluate and select the type that meets their project requirements and this should be incorporated into their project planning and design.

PRECAST CONCRETE VOLUMETRIC SYSTEM PBU

There are many types of PBU and it is essential to understand the characteristics of each type before its selection for use.

The above pictures show 2 main types viz. PBU is formed with concrete base and walls of concrete or other materials e.g. drywall, steel panel, etc. and PBU with fibre reinforced walls and floor panels. Each type has its own characteristics.

Developers, consultants and builders should evaluate and select the type that meets their project requirements and this should be incorporated into their project planning and design.

Design Considerations

Design parameters are critical for any construction work. In the case of PBU, design parameters such as structural, architectural, M&E works, installation, and subsequent maintenance challenges must be determined early to ensure that the PBU system is integrated and can be incorporated in the overall building design. A good PBU design should provide practical solutions to address potential issues arising in different stages of PBU’s life cycle including future renovation. It is also important the design meets the requirements in the Code on Accessibility in the Built Environment.

Architectural Design Considerations

a. Dimension

An efficient volumetric system requires careful consideration and confirmation of the overall dimensions. The overall dimensions and design should take into consideration space/floor area taken up by the double wall/floor systems, structural drop slab and storage heater (if any) to ensure effective use of space. The types of bathrooms should be standardized to achieve economy of scale production while providing sufficient design variation.

b. Location of Service Ducts and Access for Maintenance

The routing and connection of services should be predetermined and coordinated with the PBU manufacturer during the design stage.

c. Layout

The locations of door and window openings and layout of fixtures and M&E services should be functional and practical. The form-work mould for volumetric PBU production is dependent on the locations of these openings. It is recommended that the general layout of the prefabricated bathroom unit be provided in the homeowner user manual.

The location of the service shaft is critical to the maintenance of the precast concrete PBU.

It is important to make the vertical service shaft accessible for future repair and maintenance works of the PBU.

Structural Design Considerations

As precast concrete PUB typically weighs up to 9 tons, it is necessary to ensure that the structural strength of different types of receiving platforms are adequately designed. Use of different types of concrete, such as lightweight concrete or high strength concrete can reduce the overall weight of PBU. The design of the hoisting and lifting devices placed within the precast elements is also crucial to facilitate the installation process. The choice of structural system may have an impact on the build-ability score of the project.

a. Double Slab System

b. Single Slab System

c. Lifting and Hoisting Devices

M & E Design Considerations

The design considerations for M&E services will determine the placement and routing methods of these services.

Bathroom Production

Precast Unit Production

A good design and specification of the form-work mould is crucial for producing high quality precast concrete PBU. The steel plate thickness for the precast concrete mould must be sufficiently designed to withstand the concreting pressure. The use of checker plate form-work (for concrete surface receiving finishes) improves bonding between the finished concrete and the adhesive. Proper propping supports should also be provided during the concreting process.

To improve productivity in the manufacturing process, it is advisable to cast the base slab to the required water gradient (as indicated below) to cut down the screed process.

If the slab is cast without gradient, it is important to control the thickness of the screed to achieve the required gradient for water flow.

Architectural and M&E Works Sequence

After the completion of precast concrete shell fabrication, the next construction process will be the architectural and M&E works. The application of waterproofing as well as water-pond test is always an important process towards achieving primary functionality of the PBU. Other key architectural works include fixing of door and window frames, followed by tiling works and installation of sanitary wares and components. Adequate allowance for movement joints should be made for PBU and window and door joints openings.

It is recommended the relevant good industry practices for various trades as in the CONQUAS Enhancement Series https://www1.bca.gov.sg/Publications/EnhancementSeries/enhancement_series.html be followed.

All fragile fixtures can be installed at the last stage of fabrication to minimise possible damage. The architectural internal finishing works should be properly protected before delivery of the precast concrete PBU to site.

Protection, Transportation and Lifting

A well-planned transportation, lifting, protection and storage system for the PBU is important to ensure minimal damage to the finished product before and after the PBU is installed at the site.

Proper coordination and planning of delivery of PBU can help to resolve the logistical hassle of insufficient storage space, double handling and control of access to the PBU.

Installation

The readiness of the construction site to receive the PBU is critical to the successful installation of the PBU. It is also important to understand the different structural systems that are designed to receive the PBU at site, viz:

• Double Slab System
• Precast Beam System
• Corbel System

The key feature of the double slab system is the fixed dimension of the secondary slab to receive the PBU. It is recommended that the gap between the two slabs be grouted to eliminate any possible water stagnation issues.

For precast beam system, the PBU is directly supported on the perimeter beams and hence the positions and dimensions of these beams must be constructed precisely.

M&E Connections and Final Fixings

The installation of M&E services and fittings is probably the most critical work process in the entire PBU fabrication as it affects the functionality and serviceability of the PBU. Design for the M&E pipes and duct works shall take into consideration their connectivity to power supply, water supply and sanitary drainage.

Provision for M&E Services

Generally, there are two methods of laying the M&E services in precast concrete PBU. The M&E pipes and conduits can either be cast together with the precast concrete shell or laid via block-outs or recess, which are provided for on the external or internal surfaces of the precast concrete volumetric shell.

For embedded M&E conduits, their positions must be precise and care should be taken to ensure they are properly bent and securely fastened for long-term durability.

The selection and installation of the embedded electrical conduits should comply with the relevant Code of Practice (CP5 & CP88).

Block-outs and recesses should be sufficiently provided for in accordance to the layout of M&E services for ease of connection to the M&E fittings.

Use of Shallow Floor Trap

It is common to utilize a shallow floor trap for PBU with double slab system or when there is constraint in floor height. Unlike the conventional floor trap system where pipes are exposed at the slab soffit, the shallow floor trap and its connecting sanitary pipes are fully concealed in the slab and connected to the main discharge stack directly.

In Singapore, the use of shallow floor trap is approved by Public Utilities Board (PUB) if the shallow floor trap is in compliance with EN 1253, which comprises the following 8 tests:

• Anti-blockage test
• Water tightness test
• Flow rate test
• Odour tightness test
• Resistance of water seal to pressure
• Depth of water seal
• Access for cleaning
• Side inlet

There is no special maintenance consideration for the use of conventional floor trap in the precast concrete PBU, except for the space required to accommodate the services with the provision of sufficient floor height.

Connection to M&E Fixtures

a. Wash Basin

The water and discharge works for the wash basin in the precast concrete PBU should follow the approved method statements and comply with the relevant Code of Practice for plumbing and sanitary works. Accuracy of the penetration joints from the precast concrete PBU to the connecting accessories (i.e. hoses, taps) of the wash basin is important for its functionality and overall alignment of the wash basin.

Positions and routes of the embedded M&E services should be clearly identified to prevent accidental damage caused by the drilling of anchors and supports for the wash basin.

b. WC Pedestal

Depending on the type of water closet (WC) pedestal used, the plumbing and sanitary connections of the WC may run horizontally through the wall or vertically to the floor slab of the precast concrete PBU. Accuracy of the penetration joints and sleeves from the precast concrete PBU to the accessories of the WC pedestal is important for its functionality and overall alignment. For better aesthetics, the jointing at any pipe penetration should be concealed or covered up neatly.

c. Shower Mixer Tap

When there is provision for a shower mixer tap, separate water pipes for hot and cold water should be catered for in the design and fabrication of the precast concrete PBU shell. The routing of the different water pipes could be demarcated by coloured tapes on the finished wall surfaces for clear identification of these pipes.

Routing of Air-conditioning Drain Pipes

Air-conditioning drain pipes are normally laid through the wall and floor slab at a gradient to discharge condensate water to the PBU floor trap. The air-conditioning drain pipes could be designed to run embedded in the precast concrete PBU floor slab connecting to the floor trap. An alternative is to run the insulated drain pipes through the false ceiling (if available) and connect directly to the discharge stack.

Maintenance, Replacement and Renovation

There are differences in the maintenance, replacement and renovation of precast concrete volumetric PBU as compared to conventional toilet. Therefore, it is important for developers and builders to provide a homeowner user manual upon completion of project for instructions and advice on how to maintain, replace and renovate the PBU.

As the wall and floor of precast concrete PBU may not be as thick as conventional toilet, the selection of appropriate tools and use of recommended methods of work execution can prevent damage to the precast concrete PBU. The types of tools and execution methods must be covered in the homeowner user manual.

For M&E services that are cast-in with concrete, both the tiles and concrete need to be hacked during repair works. For M&E services that are laid through block-outs, removal of tiles or surface finishes should suffice.

Hence, it is essential to provide the M&E concealed services locations through drawings and demarcation of route in the homeowner user manual. This can help homeowners and renovation contractors minimize damage during repair and replacement of M&E concealed services.

The provision of waterproofing detail drawings can help homeowners and renovation contractors identify and prevent damage to the waterproofing during renovation, replacement and repair works.

The location of access to the vertical stack must be made known to the user through the homeowner user manual to facilitate maintenance, repair, and replacement of M&E stack shaft. With the information, the homeowner can also plan their internal unit renovation without obstructing the access panel.

Ceiling Access Panel

The ceiling access panel is a common provision for toilets with false ceiling. The function of the access panel within the precast concrete PBU is to access and maintain all M&E works above the false ceiling, similar to that for conventional toilet.

Replacement of Other Items

The replacement of sanitary items and components within the PBU is similar to that for conventional toilet.

It is recommended that the method of removal and access to the M&E stack shaft be covered in the homeowner user manual. PBU designers should also explore other possible options to access the stack shaft.

GOOD PRACTICES IN INSTALLATION, ARCHITECTURAL FINISHES, M&E SERVICES AND RENOVATION

While it is possible to achieve high quality PBU by following closely approved work procedures, adopting good practices in installation, M & E services and renovation of PBU can often lead to greater productivity and better user experience. This may require the employment of professionals and more skilled workers to achieve higher quality standards. However, as every project’s objective may be different, it may be necessary to be selective or customize the suggested good practices mentioned herein to suit each project.

Installation

The precast concrete PBU is the sturdiest and heaviest PBU available. Therefore the design of the receiving platform and installation is critical to the success of the PBU installation. As the precast concrete PBU typically weighs up to 9 tons, the slot-in (non- critical path) method may not be suitable and hence, the top down (critical path) installation is often used. For top down approach, coordination is critical and protection of finishes can be challenging.

It is necessary to ensure that the structure of the receiving platform is adequately designed. The selection of single slab or double slab types for receiving platforms is often determined by the floor to floor height and other considerations e.g. ease of tracing seepage or leakage, etc.

Double Slab Approach

Pros

• Base slab facilitates ease of installation of PBU

Concerns

• A challenge to trace leak
• Reduces headroom

Edges at gap between slabs should be sealed to prevent water ingress during construction

Single Slab Approach

PBU resting on precast beam edge

Pros

• Easier to trace water leakage

Concern

• Need more precise co-ordination during installation

PBU resting on corbel

Pros

• Easier to trace water leakage
• Able to install complete finishes with fittings

Concern

Need more precise co-ordination during installation

Architectural Finishes

It is recommended to cast the floor slab of the precast concrete PBU with a gradient to reduce some work processes such as screed works.

Floor slab gradient

• Gradient to fall in both directions
• For slab without gradient, need to control thickness and quality of the screed

Waterproofing works

• Water proofing works to commence after structural pond test

Tiling works

• Tiling work is done over render and screed

Other works

• Other works such as cabinets can follow

Long Bath

• Use metal frame for long bath installation instead of bricks or blocks

M & E Services

The choice of M & E services must take into consideration conduct of tests and future maintenance.

Location of Stack Pipes

• Location of stack pipes and orientation of shaft within unit is important for future maintenance, repair and renovation
• Locating pipes at or facing external wall will pose greater challenge for replacement and repair

Concealed Services

• Cast in concealed piping
• Block-out within PBU make replacement easier

Conventional Floor Trap

• Maintenance and repair similar to conventional bathroom
• It is important to have sufficient floor height

Shallow Floor Trap

• Select brands approved by PUB
• To comply to BSEN 1253 standard
• Test certificates required
  – Anti-blockage test
  – Water tightness test
  – Flow rate test
  – Odour tightness test
  – Resistance of Water Seal to Pressure
  – Depth of Water Seal
  – Access for Cleaning
  – Side inlet

Routing of Pipes Above PBU

• route pipes near the edge of PBU (reachable from outside) or accessible via ceiling access panel

Air-conditioning drain pipe (Concealed)

Pros

• Connect to floor trap and cast in, do not require false ceiling

Concern

• Unable to achieve sufficient gradient within slab thickness

Air-conditioning drain pipe (through slab)

Pros

• Can achieve sufficient gradient Concern

Concern

• Need false ceiling and sufficient headroom

Renovation

Although precast concrete PBU is similar to conventional bathroom, it is essential to exercise care during renovation to prevent damage to the PBU. A trained renovator should be engaged who should use appropriate tools and follow the instructions in the homeowner user manual.

• Renovator should be trained
• It is important to use appropriate tools for renovation works
• Exercise care when renovating and replacing tiles by referring to the homeowner user manual

Homeowner User Manual

Besides engaging renovation contractors who are trained, homeowners should have a ready reference of the PBU system used in the unit. It is good practice for developers/builders to provide a homeowner user manual of the PBU upon completion of the project. The homeowner and subsequent buyers of the unit should obtain a copy of the homeowner user manual after taking over the unit and follow the recommendations on PBU renovation provided in the manual.

The information in the homeowner user manual could include (but not limited to) the following:

(a) General information on PBU

(i) Introduction to the PBU installed
(ii) Safety notices
(iii) Instructions for use

(b) Structure of the PBU

(i) Floor
(ii) Wall
(iii) Ceiling
(iv) Water piping
(v) Sanitary discharge pipe/vertical soil stack
(vi) Electrical conduits

(c) Layout of the PBU

(i) General layout
(ii) Waterproofing layout
(iii) Locations of concealed services
(iv) Location of access panel
(v) Location of the manufacturer’s label

(d) Cleaning and maintenance advice

(i) Internal fittings, tiles and accessories
(ii) Floor trap
(iii) Ceiling access panels

(e) Alteration, repair and replacement works

(i) Replacement of accessories/installation of additional fittings
(ii) Availability and supply of spare parts
(iii) Instructions for drilling and fixing
(iv) Instructions for tile replacement
(v) Instructions for grab bars installation

CRITICAL INSPECTIONS AND QUALITY CHECKS

Critical Functionality Inspection and Tests

Every construction process requires inspection or testing to ensure its functionality. The functionality of PBU is critical and needs to be inspected or tested from fabrication to installation either at the precast yard or construction site.

M&E Provision

It is important to ensure all the M&E cast-in-items/block-outs are provided in the correct position and properly secured during fabrication. M&E services functionality depends on the proper securing of these block-outs during concreting. All works should follow the M&E, sanitary and plumbing approved method statements and construction drawings.

Waterproofing Works

Water tightness is one of the primary functionality of PBU. To achieve quality waterproofing works, an effective waterproofing method should be developed. The BCA’s Good Industry Practices “Waterproofing for Internal Wet Areas” under CONQUAS Enhancement Series is a good reference for development of the approved method statement. The waterproofing in-process installation, inspection and testing should then be conducted in accordance to the approved method statement.

Shallow Floor Trap Tests

The floor trap is crucial towards the functionality of a bathroom. Manufacturers can choose among the conventional P, S or shallow floor trap. When using shallow floor trap, it is essential to ensure that it has been tested and meet the following requirements:

• Anti – blockage test
• Water tightness test
• Flow rate test
• Odour tightness test
• Resistance of water seal to pressure
• Depth of water seal
• Access for cleaning
• Side inlet

Pipe Pressure Test

Pipe pressure test will determine the ability of the pipe and its connection to take the stipulated pressure. The test should be conducted in accordance to the approved method statement. All pipes in PBU should be pressure tested.

Tiling and Tile Pull-Off Test

To achieve quality flooring and wall finishing works, it is recommended to conduct in-process tiling installation inspection and, if applicable, wall tiles pull–off test to an approved method statement as in BCA Good Industry Practices Guides on “Ceramic Tiling” or “Marble and Granite Finishes”.

Grouting

It is important to seal up the gaps between slabs for double slab system, by grouting. It is recommended to follow the grouting procedure according to the approved method statement.

Quality Checks

Process checks during every stage of the bathroom unit production are important to ensure a high quality final product is achieved.

Structural Works

Checks on form-work, reinforcement and concreting defects should be made progressively in accordance to the specified requirements.

It is recommended that the PBU base slab is concreted to the desired gradient to receive the tiles. This method is highly productive and it reduces defects by removing the need for thick screed for floor tiling works.

Architectural Works

Upon completing PBU fabrication, it is important to conduct quality checks to approved architectural internal finish standards before delivery.

Floor, wall and ceiling should be checked on finishing, alignment and evenness, crack and damages, roughness, and jointing.

Door, window, component and M&E works should be checked on joints and gap, alignment and evenness, material and damages, functionality, and accessories defects.

The final check before the PBU is delivered to site will be the protection work, internally and externally. It is important to protect the completed PBU before delivery. The protection of the PBU should not be removed unless necessary until after installation and access to the PBU must be controlled after removing the protection.

It is recommended to have another round of checks once the protection is removed to ensure the PBU meets the design and specified requirements.

Source: Building and Construction Authority