On-site Insight 7 - 2007

On-site Insight

241 Northbourne Ave, Lyneham Canberra ACT 2602 Tel: (02) 6247 2099 Fax: (02) 6249 8374 www.mba.org.au

Congratulations!

Problems with Rendering and Painting below Damp Proof Course General Observation Rendering and Paint Work that is displaying blistering and slight delamination mainly below damp proof course level (DPC) is quite common, in some form, in most newly rendered buildings especially below DPC level.

These problems usually become evident approximately twelve months following the completion of the work. The nature of this defect is minor and non structural.

Likely causes associated with this type of defect There are small amounts of soluble salts found in new bricks and Portland cement used in mortar. The mechanism for this minor salt damage to the surface render and paint is as follows; as small amount of salts are dissolved in water and absorbed by porous bricks and mortar or moisture in the wall dries, the concentration of soluble salts in the wall increases. When the decreased volume of water or moisture can no longer dissolve all the salts, crystallisation begins and pressure is applied to the surface coating or render. When this occurs near the surface of the coating or render, the pressure on the material may exceed its tensile strength and cause delamination of the render or blistering of the paint finish.

It is unlikely that efflorescence results from soluble salts naturally contained within the brick. Most Australian bricks exhibit little or no efflorescence. Nearly all efflorescing salts come from other sources such as the mortar ingredients and ground water. The salts in mortar may be brought to the surface as newly laid brickwork dries out to cause what is generally known as “new building bloom”. This bloom is primarily caused by drying out of construction water that brings to the surface free alkalis in the mortar. At the surface these free alkali solutions react with the atmosphere to form a whitish powdery substance. If render is applied to new work it is quite likely that all these salts have not been expelled, but over time will build up at the interface of the render and the background. Some of these salts do not make it to the surface but some do causing delamination of the render or blistering of the paint finish as noted above.

Remedial Action The first step is to determine the cause of the problem and identifying the salts that are present will often assist in this process and thus help to determine appropriate action. The salts visible on the surface can be removed by a relatively simple process as follows; firstly remove all loose and flaking render or applied finish, secondly choose a fine day and dissolve 250 – 350 grams of sodium hydroxide (caustic soda) in four litres of water, wear full protective clothing including gloves and goggles while carrying out this task. Using a brush, liberally coat the affected salt damaged render or finish with the solution and leave for three days to neutralise the salts. Take care not to splash the solution on any adjoining surfaces.

After three or four days wash the wall with clean water, the majority of the salts should then be expelled and the render finish can be repaired and repainted as a normal process.

The following actions may be considered Good Building Practice to minimise defects below DPC in rendered and painted buildings 1. Use exposed durable face brick finish in the band below DPC level.

2. Ensure that the bricks below DPC level are covered to prevent water entering the bricks during the construction process e.g. drape membrane over the brick wall to prevent surface water from the concrete slab entering the brickwork.

The Master Builders salutes the following Members in reaching significant milestones and for their invaluable contribution to the Construction Industry in the ACT & region.

50 40

Years

Woden Contractors Years

W.R Engineering

25

Years

Blackett Homes

In This Issue

Asbestos ALERT

Contractors/ Subcontractors Are they workers or employers?

Design Considerations for Polished Concrete in Wet Areas Australian School-Based Apprenticeships

3. Ensure that a splash coat of 1:1 coarse sand/cement is applied to the brickwork/masonry to achieve maximum bond with the substrate.

Problems with Rendering & Painting below DPC

4. Use approved waterproofing additives in the render mix below DPC level to minimise ground water entering the render.

Important Dates

5. Use proper approved tanking systems to waterproof walls at split levels and where it is likely that moisture from fill under slabs will migrate through the masonry to the front of the wall.

6. Ensure that the DPC extends past the applied finish to prevent moisture wicking up the render.

7. Always install a proper V joint at the DPC junction in the render. This must be a clearly pronounced joint and not a slight indent in the render to prevent spalling and fracturing of the render at this location.

Friday 16 November Annual Dinner Monday 25 February 08 Master Builders Golf Day

Training Dates 23 & 23 November OH&S Risk Management for Managers & Supervisors

MEMBER ALERT

November 2007

Will you or any of your employees be working illegally from 18 November??

If you work in the trades, maintenance and services sector of the Construction Industry there’s a good chance you will need to work with small amounts of bonded asbestos, as part of your daily work activities.

In the ACT, you must be trained to work with and remove any amount and type of asbestos. It is important that you get the skills you need to handle it safely and avoid health risks. Otherwise, engage a licensed asbestos removalist.

The legislation relating to the removal of asbestos commenced on 1 July 2006. However, the provisions, namely the transitional arrangements commenced on the 18 November 2006.

These transitional arrangements mean that builders can still remove bonded asbestos until their license expires or up until the 19 November 2007, whichever comes first. From the 19 November builders will require endorsement on their builders licence if they are undertaking work involving the removal of bonded asbestos.

Asbestos removalists’ licensing You must be licensed to remove any loose asbestos and over 10m2 of bonded asbestos.

Types of licences There are two specialist classes of asbestos removalists.

Asbestos removalists Class A: licensees can handle (include disturbing) asbestos in buildings, and remove and dispose of asbestos from buildings; and Asbestos removalists Class B: licensees can handle (include disturbing) only bonded asbestos in buildings, and remove and dispose of only bonded asbestos from buildings.

Builders, tradespeople, maintenance and services providers in the construction industry can work with or remove asbestos, if required in the course of their daily work activity, as exempt building work only if: • the asbestos is bonded asbestos; and • not more than 10m2 of asbestos is handled during the activity; and • each person who handles the asbestos • Works in a prescribed occupation; and • Has a relevant asbestos qualification; an • The asbestos is handled by each person who handles it in the course of their occupation The MBA strongly recommends that builders, tradespeople, maintenance and services providers, should undertake the accredited course offered (see important dates) to ensure that when the transitional arrangements expire they will comply with the legislative requirements.

To register for asbestos training contact Norma Inglis on 6247 2099 or email norma@mba.org.au

AN INDUSTRY UPDATE FROM THE MASTER BUILDERS ASSOCIATION OF THE ACT

On-site Insight Workers Compensation in the ACT CONTRACTORS / SUB-CONTRACTORS Are they workers or employers?

Could a contractor or sub-contractor could be a worker, employer or even both?

There appears to be some uncertainty, particularly in the construction industry, regarding the meaning of worker & employer. Many ‘contractors’ in the construction industry are being told they are required to ‘take out’ workers compensation insurance to cover themselves when in fact, depending on their circumstances, a contractor may be considered a worker of the business contracting them.

The Workers Compensation Act 1951 (the Act) requires all employers in the ACT to have a workers compensation insurance policy in place to cover their workers in the event of a workplace related injury.

The Act states an employer includes • an entity; and • the legal personal representative of a dead employer; and • if the services of the worker are temporarily lent or let on hire to someone else (the temporary employer) by the person (the original employer) with whom the worker has entered into a contract of service or apprenticeship—the original employer is, for this Act, taken to continue to be the employer of the worker while the worker is working for the temporary employer.

An employer may be someone who employs workers under a ‘contract of service’. A contract can be made either orally or in writing, and applies to full time, part time and casual workers.

For the purpose of workers compensation, the definition of a worker may also include regular contractors and casuals who work: • under a contract on a regular and systematic basis; or • who have a reasonable expectation of their engagement continuing on a regular and systematic basis.

Additionally, under Territory legislation if a contractor (the principal contractor) subcontracts any part of the work, they may be liable to pay workers compensation for a worker employed by the sub-contractor. This can occur when the sub-contractor does not have adequate workers compensation insurance to cover its workers.

If the principal pays workers compensation to a worker of a sub-contractor, they would be entitled to seek reimbursement from the sub-contractor if they were deemed to be a person who would have been liable to pay compensation to the worker if they had held a compulsory workers compensation policy.

On-site Insight Example 1: Freddy McKellar is a labourer and works for Tom Knight, a brick-layer, and has done for about 7 weeks. Tom employed Freddy to assist him complete a job for DK Constructions.

By being aware of your workers’ compensation obligations and implementing strategies to meet these requirements, you are contributing to providing a working environment that ensures the health, safety and welfare at work of all workers.

Tom Knight is Freddy’s employer. If Freddy was injured during the course of employment, and Tom doesn’t have a workers compensation policy, Freddy may claim compensation from DK Constructions as the principal.

If Tom makes a claim for compensation against DK Constructions, DK Constructions is entitled to be indemnified by Tom Knight.

Please note that all cases are different and should be assessed individually. You should always refer to the appropriate Acts, seek legal advice or contact the Master Builders on 6247 2099.

Example 2: Tim Jones is a carpenter. He is a sole trader and therefore unable to take out a workers compensation policy to cover himself. He has his own ABN – pays his own taxes & GST. His main source of income is from Mario of Mario’s Building Services. He has worked for Mario for 6 months and works most Mondays to Fridays for Mario.

Mario has a contract with Tarango Constructions to do the carpentry at Complex 481, a block of apartments in the city. Tim has been working at the complex for Mario in the city for the past 4½ months and the job is only half completed.

Tim Jones would be considered a worker. Mario is Tim’s employer. If Tim is injured, and both Mario and Tarango Constructions do not have a current workers compensation policy, Tim would need to make a claim under the safety net arrangements, the Default Insurance Fund (DI Fund).

It should be noted that if an employer fails to maintain a compulsory insurance policy, and a claim has been made to the DI Fund, the DI Fund is entitled to recover up to three times the amount of compensation paid to the injured worker and up to three times the premium that would have been payable to an insurer.

The Office of Regulatory Services may also apply penalties for not maintaining a compulsory workers compensation policy in the ACT. The maximum penalty is 250 penalty units, being $25,000 for an individual, $125,000 for a corporation and/or imprisonment for 2 years.

To avoid this situation, principal contractors should ensure that all sub-contractors who employ workers have the correct workers’ compensation insurance in place to cover those workers.

In 2005/2006 there were over 490 accepted claims in the private sector construction industry, totalling an estimated cost of over $12 million. Given these figures, the number of sub-contractors employed, and the degree of risk associated with the type of duties performed by workers in the building and construction industry, it is imperative that all employers within the industry understand their obligations with respect to workers’ compensation insurance coverage for their workers.

Design Considerations for Polished Concrete in Wet Areas The current practices for waterproofing polished concrete floors in showers and wet areas have not been properly considered and methods for sealing these floors can lead to water escaping from the wet areas into adjoining areas. Some of the current practices used in waterproofing polished concrete involves treating the concrete with an admixture to prevent water penetration and spraying the surface with a transparent sealer. The objective of this is to waterproof the floor and retain the look of polished concrete.

This method can fail because the transparent sealing coat can be affected by cleaning chemicals used in showers.

The coating does not comply with the requirements of AS/NZS4858, namely membranes used in showers.

One part of the key requirements of the test to meet AS 4858 is to subject the membranes to chemical attack.

Many showers have failed because the waterproofing system has been damaged by chemicals.

Other issues are, the sealing coat applied to polished concrete may not bond to the waste outlet, which can cause a leak at the pipe penetration. Also movement at the wall/floor junction could rupture the transparent sealer creating a lack of proper flashing at the wall/floor junction.

Depending on the type of shower screen to be used, it may not be possible to install a water stop at the perimeter of the shower. The problem here is that if a water stop was installed during the placement of the concrete it would have to finish above the level of the polished concrete to be effective. The lack of a proper water stop could allow water to escape into adjoining areas.

To address these issues a preferred option is to fully recess the wet area and apply a waterproof membrane including a wall/floor junction flashing to the perimeter of the bathroom. A concrete screed could then be placed, graded to the wastes, cured and then polished. The concrete would then finish flush with a water stop at the doorway.

To achieve this outcome in concrete or brick buildings, a number of design considerations arise.

For suspended floors the bathroom must be set down 100mm and drainage flanges installed to the wastes.

Where the bathroom is a slab on the ground, the drainage pipes should have a minimum diameter of 80mm. The membrane is then installed with the perimeter flashings being designed to finish 50mm above the finished surface of the concrete floor. The vertical junction of the shower wall will also have been sealed at this time. Concrete for the polished floor is then installed. It is a requirement that showers have fall to wastes in accordance with AS 3740 2004.

In buildings where sheet lining is used, the method for waterproofing the floors is identical with the flashing applied to the face of the wall sheet. The up stand in the waterproofing will be covered by the skirting tiles to the perimeter of the bathroom.

The methods described above still require a high quality water-resistant admixture added to the decorative concrete during the batching process. This is to prevent any ingress of moisture into the concrete slab due to sealer breakdown which could lead to contamination or fungal growth.

Australian School-Based Apprenticeships Master Builders Group Training has enjoyed a very successful year with the Australian School Based Apprentice (ASBA) programs. So far this year we have had 38 students successfully complete their Certificate II in General Construction, and a number of those students have applied for a full time apprenticeship with Master Builders Group Training or taken on apprenticeships through private employers. Over the past 18 months, these students have been working with a variety of Host Employers and completing theory-based training with Master Builders Group Training alongside their year 11/12 curriculum studies at College.

Master Builders Group Training has also placed all the students involved in the ‘Kids Assist Program’ with Bovis Lend Lease (Alexander Maconochie Centre) and PBS Building (82 Northbourne). These students were identified by their high schools as ‘students at risk of not completing their Year 10 studies’. This program has given them the opportunity to gain an insight into the building and construction industry alongside school studies.

The Host Employers who volunteer their time and expertise to these programs have been invaluable. For the majority of students in the ASBA programs, the experience they have gained has been life changing.

It is also a valuable contribution to addressing skills shortages within the industry.

Master Builders Group Training is always keen to find new Host Employers to help train these students. The students are interested in a variety of trades and work with both residential and commercial builders. If you are interested in participating in the ASBA programs and helping train the trades people of tomorrow, please contact Master Builders Group training on 6280 9119. “no training today, no trades people tomorrow .... “

AN INDUSTRY UPDATE FROM THE MASTER BUILDERS ASSOCIATION OF THE ACT