To minimise cracking in walls caused by thermal expansion, contraction, foundation movement, drying shrinkage etc joints should be located in accordance with the following guidelines … the project architect and engineer should be involved in the locating of control joints … for further guidance and guidelines see [another publication] … In no circumstances should a movement control joint be rendered across.
12 The Handbook contained some recommendations and some imperative terms. It also included drawings with details about a variety of matters. The appendices to the Handbook consisted of separate sample specifications for the blocks and panels. Slater Lomas, had issued a note that all the block work was to be installed "strictly in accordance" with the manufacturer's recommendation in the Handbook and that the block work was to be "fully articulated by placement of control joints at maximum of 6.0m spacing and as indicated on plan in accordance with [manufacturer's] recommendations" (par 41). The Referee considered that that note "constituted a detail which, read with the specification, required Austruc to work in accordance with the handbook, except to the extent that there were instructions to the contrary" (par 52).
13 The Referee referred to CSA's submission that one of the drawings, W3, showed that the sealant was detailed to the external face of the blocks and not rendered over (par 57). The Referee also referred to Austruc's contention that the instructions given to it permitted it to render across the control joints and that the Handbook was not clear about this. The Referee reported that he did not agree with this contention and referred back to the statement in section 7.4 of the Handbook that in "no circumstances should a movement control joint be rendered across".
14 The Referee also reviewed whether the requirements in the Handbook had been varied by analysing communications between CSA, Slater Lomas and Austruc (par 59-62). The manufacturer wrote to Slater Lomas with a "sketch" of its thoughts for the Building. The Referee recorded that this sketch set out considerable detail of what should be provided by Austruc, by way of control joints and fixings between the Hebel blocks and the concrete framework of the Building. This was apparently done by reference to drawing W3 from the Handbook. That showed where the control joint should be placed between the Hebel blocks and the columns on either side of the block work panel, and between the Hebel blocks and the soffit of the slab at the top of the panel. The Referee recorded that the drawing provided that the joints should be 10 mm or more wide, and that they should be filled in with a backing rod, and sealed with a polyurethane sealant. The Referee concluded that to his mind, "it shows that render should not be placed over the sealant" (par 59).
15 The Referee recorded that Slater Lomas checked the position and approved the details of the sketch and advised CSA of that position and asked CSA "aren't the hebel walls to be waterproofed? If so then galvanised dowels may be ok. Your thoughts?". That communication was also given to Austruc who advised that they were a builder and "not a designer". Austruc also advised that it had informed CSA of the "lack of suitably documented detail in relation to the fixings between windows and Hebel blocks, and that this was a problem for "the design team" to overcome" (par 61).
16 The Referee concluded that these exchanges showed that Austruc was to act, so far as the Hebel block work was concerned, in accordance with the Handbook, except where there were specific instructions to act otherwise. The Referee noted that these communications said nothing about making the Building watertight (par 63). The Referee then set out some evidence given by an employee or officer of CSA, Mr Smith, in which he was cross-examined about his observations as to whether the control joints had been rendered over. He agreed that it was obvious when he looked at the Building at practical completion that there were not 10 mm open-face construction joints in the locations that had been indicated on the drawing. He accepted that the engineer had specified 10 mm wide joints and that he had passed that specification onto the builder. The Referee was not satisfied that Mr Smith had noticed that the joints had been rendered across or if he had, he did not regard it as significant at the time. The Referee rejected Mr Smith's evidence that rendering over control joints was consistent with good practice (par 66).
17 The Referee identified that each of the experts (Messrs Alden, Dunstan, Knox, Plaister, Skinner, Smee and Wilkinson) said that "good practice did not permit the rendering across of these joints" and observed that this was a "matter that goes to both the design responsibility and the quality of the work". The Referee also referred to Mr Alden's evidence that by rendering across a movement joint "you are guaranteed to have cracks and spalling" in the render. The Referee recorded that he accepted that evidence (par 67-68). He then reported: