I recently had an engineered wood floor laid in my flat. Half way through the fitter flagged that there was a problem with the floor - specifically that the planks were not thoroughly coated with protective oil. We stopped work and the suppliers came to inspect the planks. They said it was fine and that the difference in finish on the planks was caused by different levels of sap content in the wood.
We finished laying the floor and within days hours all the protective oil had flaked off all of the planks. Sine then some of the planks have split down the entire length of the planks. The supplier is saying the floor must have been badly laid for these two things to happen. The fitter didn't put down a damp proof membrane and has said it was necessary as the existing floor (plastic tiling) acted as a damp proof membrane. Does anyone know whether the oil coming off the floor and/or some planks cracking could be caused by not having put in a damp proof membrane?