"MATERIALS – the property in unfixed materials shall not pass until all materials shall have been paid for in full. All materials on the site fixed or unfixed are at the sole risk of the client and in the event of any of the same being damaged, destroyed or stolen, we shall be entitled to full payment therefore, and also for any work damaged, destroyed or lost, and the cost of replacing and of reinstating or restoring any such work shall be charged as an extra, provided that the client shall not be responsible for any loss occasioned solely by the negligence of our employees". (b) clause 15: "works covered by the this estimate, existing structures in which we shall be working, and unfixed materials shall be at the sole risk of the client as regards loss or damage by fire and the client shall maintain a proper policy of insurance against that risk in an adequate sum. If any loss or damage affecting the works is so occasioned by fire, the client shall pay to us the full value of all work and materials then executed and delivered".