This is a fuming chamber where heat and ammonia are introduced once the chamber is sealed. The Oak top layers are placed inside with timber spacers between them to allow the heated ammonia saturated air to circulate. Fuming is a specialist process and depending on the final colour required the time taken can be a few hours to several days.
You can see here how the layers are spread out between thin wood battens to allow for full circulation so that the complete thickness of the top layer is fumed. This is important as in high traffic areas “Stained” wood can scratch whereas properly fumed oak like ours will be the same colour all the way through.
There will always be a lot of colour variation due to the process. If you look in old horse stables with oak beams you can see some of the variety of colours that can be created.
We try to reduce this but at it is a natural product you must expect the colour variation and it helps to create the beauty of a natural floor.