Kitchen Wall Layout Conflict With Drawing and Service Pipe
A commercial kitchen wall is 2,870 mm wide and 2,400 mm high. The specification calls for 300 × 600 mm rectified porcelain in stack bond with 3 mm joints. The approved drawing starts a full tile at the left door jamb and shows a 20 mm cut at the right corner, with a 5 mm movement joint at the ceiling. On site, the left jamb is 8 mm out of plumb over the full height, and a 25 mm service pipe sits 150 mm from the right corner, floor to ceiling. The tile module is 303 mm. The foreman wants to start from the drawing and make the cut work. You are asked to check the setting-out before any adhesive is mixed.
1. Calculate the actual layout from the site dimension and identify the drawing discrepancy.
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Module = 300 mm tile + 3 mm joint = 303 mm. Actual wall: 2,870 ÷ 303 = 9.47 modules.
Starting with a full tile at the left gives 9 full tiles = 9 × 303 = 2,727 mm, leaving 2,870 − 2,727 = 143 mm at the right, not 20 mm. A 20 mm cut with a full tile at the left would imply a wall of about 2,747 mm. The drawing was probably scaled from a different opening or ignored the joint module. The 8 mm out-of-plumb jamb also means a full tile placed tight to the jamb will either be tapered or will require scribing, and the taper will show in the field if the layout starts from that jamb. Do not proceed on the drawing dimension alone.
2. Propose a revised setting-out that avoids a sliver and handles the pipe and out-of-plumb jamb.
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Use a balanced layout: 8 full tiles = 2,424 mm; remainder = 2,870 − 2,424 = 446 mm; two end cuts of 223 mm each. This avoids a 20–143 mm sliver and puts a substantial cut at each corner. Set a centreline at 1,435 mm from either side and check with a laser. Scribe the left first tile to the 8 mm out-of-plumb jamb so the taper is hidden at the corner, not in the field. At the right, the 25 mm pipe falls within the 223 mm cut: drill a 35–40 mm hole with a diamond core, split the tile if necessary, leave 2–3 mm clearance, and seal with neutral-cure silicone rather than grout. Maintain the 5 mm ceiling movement joint and keep it free of adhesive and grout. Dry-lay three courses before mixing adhesive.
3. How would you document and communicate the problem before work proceeds?
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Raise an RFI with: drawing number, specified dimension, actual site dimension, calculation (2,870 ÷ 303 = 9.47), photo of the jamb plumb and pipe, proposed balanced-layout sketch, and a request for approval. Do not proceed on a verbal instruction to make it work. In the RFI state the consequence: starting full at the jamb gives a 143 mm cut, not the drawn 20 mm, and a tapered cut due to the 8 mm plumb deviation. Ask for confirmation of the movement-joint detail and pipe-penetration sealing. Record the response and issue a site instruction to the crew. Keep a copy in the quality file. If approval is delayed, work in an area that does not depend on the disputed layout.