Level Dimension Tolerance - General Principles

The level & tolerance policy relates to the delivery of construction works how they are supposed to be to deliver the works to the quality required – the size, shape, surface finish, location and allowable variance from these documented requirements.

Project after project, the structural works in particular are completed in a substandard manner and require tens of thousands of dollars of rectification which commonly takes weeks of delays to following trades to be in an acceptable condition for the finishes trades to commence. The expectation for the finishes trades to “cover up” the sins of the structure, to make a “silk purse from a sow’s ear” is simply not good enough and unforgivable.

Supervision

On reviewing the problems encountered on many sites, it is clear that it is our supervision that sets apart a good quality product to one that is poorly constructed. It does not take any longer to get a level slab or to build openings to the correct dimension (& Square) than it takes to get it wrong – it just takes care and attention outside the office and that is determined by the leadership that our supervision provides.

It is unacceptable and unprofessional the quality of work some of our site teams will allow to happen on sites. Forget blaming the structural trades for delivering substandard quality. You are responsible for the works, and what you allow them to get away with is a reflection on you. This subsequently reflected on Hutchinson Builders and our ability to gain further work.

Unsupervised trades (Particularly structural) will typically slap it together and do as little as they are made to so they can move onto the next job - Look no further than the 10 concreters sitting around for 2 hours pre-pour doing nothing with a un-calibrated laser or dumpy levels beside them and then post pour saying they had to pour a slab out of tolerance because the steel was high. Subsequent trades know the teams and add cost to cater for the lack of supervision. The cost end up being greater than it would have if the works started and continued correctly.

The costs incurred through grinding of poorly finished slabs and rectifying incorrect opening sizes can be great but are one of the simplest of all of the Top 15 to remedy.
The potential for cost savings through our ability to guarantee substrate quality and opening dimensions is significant. It allows manufacturers to gain efficiencies in production bring costs down and improving programme.

Above - Rebate formed out of location followed by unacceptable block laying (mortar bed can not exceed 10mm as per AS3700 4.9.1). Rectification includes removing blocks, scabbling slab, correcting the rebate.

Above - Extensive patching of floors

The care taken in completing structural works needs to improve considerably. This means you are required to:

1. Have thorough knowledge of what is required – the drawings, specifications, standards applicable, appreciation of the following trades needs and understanding the application of the works (is it a warehouse back of house, or an off form façade to a hotel foyer) - KNOW what you are required to achieve prior to starting and tell the trades what is required and enforce it.

2. Supervise the works – prestart meeting dictating the requirements with the subcontractor before they come to site to make sure they send the right people, prestart with the people on site doing the works, check the works progressively (it’s easier to pull up works that are wrong when they are just underway rather than complete), complete your OWN measures/level checks for accuracy – CONTROL the works in progress to make sure they are completed how they are supposed to be. No hiding in the office. Evidence this using QA checklists.

3. Check the works on completion - survey the completed works – identify what works are not complying immediately to determine how to avoid the same situation on the next pour which might be a week or less away. REDUCE the risk of doing the same mistake again and again - Give this feedback to the trades immediately so that they can rectify the works and prevent the reoccurrence of an error.

Trades

The trades that cause the most defect rectification costs are;

1. Concrete place and finish
2. Formwork
3. Block work
4. Structural Steel

Above - Pour compaction of the concrete in a shear wall and poor rectification