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Contractor (March 2013) Communication is Key to a Successful Outcome

10 Mar 2013

Rob Gaimster
Cement & Concrete Association (CCANZ)

There are many decisions which can make or break a construction project.  Yet, regardless of the choices made the key to a successful outcome is effective communication.

Financial arrangements aside, the choice of architect, engineer and builder are crucial, as are the overall design and material selection.

However, it is a clear understanding of collective responsibilities and expectations between all parties that is the over ridding win-win factor.

NEW CONCRETE DRIVEWAYS

An interesting situation has emerged in Canterbury over recent months as a number of homeowners get their concrete driveways reinstated following successful earthquake insurance claims.

In this instance, homeowners are liaising with their insurance companies over the replacement of their concrete driveways, who in turn co-ordinate with the concrete placer.

It seems that a disproportionate number of new driveways are being rejected shortly after placement as homeowners believe a satisfactory finish has not been achieved.

However, in the vast majority of circumstances, the homeowner’s expectations of their new driveway’s finish have not been ideally managed.

This current arrangement with the insurance companies distances the homeowner from the concrete placer at the outset, meaning that what should realistically be expected in terms of the new driveway’s appearance is not always communicated.

UNIQUE IN-SITU CONCRETE

Concrete is unique amongst contemporary construction materials in that its temporary plastic state allows it to take on the contours of the formwork into which it is cast, as well as achieve an unlimited range of surface finishes.

Concrete offers incredible flexibility of shape and diversity of finish.

Yet by its very nature, (in-situ) concrete will reflect the vagaries of the environment in which it is placed.  No two placements of in-situ concrete will be identical – a major factor in its appeal.

Within reason, subtle colour variation, inconsistent aggregate distribution and minor cracking may occur.

These possible outcomes should be communicated to, and embraced by, the homeowner as characteristics of their distinctive concrete driveway – none of which compromise its structural integrity.

In the hands of an experienced placer, who has considered the various design and constructionfactors, the finished concrete driveway should satisfy the homeowner’s aesthetic and functional requirements.

CRACKING

Awareness around concrete’s potential to crack deserves special mention, as it appears to be the area of most concern for homeowners.

Cracks may occur in concrete construction for a variety of reasons.

For instance, like most other building materials, concrete moves with changes in its moisture content.Specifically, it shrinks as it loses moisture.

Cracks may also occur due to settlement of the concrete, movement of the formwork before the concrete member is able to sustain its own weight, or due to changes in the temperature of the concrete and the resulting thermal movement.

Appropriate measures will at least minimise, if not entirely prevent, these forms of cracking.

In all cases, joints at appropriate intervals will control cracking and ensure that it does not occur in a random fashion to the detriment of the appearance and long-term durability of the driveway.

BEST PRACTICE

A key objective for CCANZ is to ensure that industry realises the full potential of concrete as key to a sustainable built environment.

One method used to achieve this is the delivery of industry solutions based on technical expertise.

In terms of realising a successful residential concrete driveway, CCANZ is active in communicating best practice around the planning, design, construction, maintenance and specification aspects.

For instance, the recently released CCANZ Information Bulletin IB 80 Residential Concrete Driveways and Paths outlines recommended planning practice in such areas as drainage provisions, accommodating trees and adjacent structures, as well as appropriate surface finishes.

The freely available leaflet also covers design aspects such as concrete strength, thickness, reinforcement, crack control and surface tolerances.  Correct subgrade and sub-base preparation, reinforcement fixing, formwork erection, concrete ordering and placing are also outlined, along with the selection and application of the most appropriate sealers.

FINISHED PRODUCT

Installed by an experienced placer who is proficient in best practice, using concrete that complies with NZS 3104 Specification for Concrete Production, a residential driveway can be expected to meet all theneeds of the homeowner over its minimum expected life of 50-years.

Membership requirements of the New Zealand Master Concrete Placers Association include strict standard of knowledge and practical experience, both in terms of workmanship and business acumen.

From an aesthetic perspective, the homeowner has the potential to enjoy a range of colours, surface finishes (e.g. exposed aggregate), patterns (stencilled and imprinted) as well as curved or angular shapes – all of which can complement the design and landscaping of the residence.

In terms of functional requirements, the durability of concrete essentially negates the need for on-going maintenance.

ENHANCED COMMUNICATION

The replacement of earthquake damaged driveways will form an important part of the construction scene in Canterbury over the coming months.

As such, CCANZ will be working with the insurance industry across the region in an effort to ensure their representatives both appreciate and convey all aspects of concrete construction as it relates to driveways.

Armed with a fuller understanding of what they should realistically expect in terms of concrete construction, homeowners will be able to concentrate on other areas of their lives without worrying about their driveway.

Article appeared in Contractor magazine.