Yes, that is why the strips are there, plus to let the water seep out. If the tongue and groove would warp it would or could pop upwards and crack the tongue. The wood needs to move as moisture is added or taken away. The strips also let air get in between boards to dry them out. That is why it is also important to seal the edges of the boards. But I am sure someone has tried the tongue and groove method, maybe it will work for awhile, but in the long run I personally wouldn't use it. I have some photos on my site of the purpleheart and cherry boards that I milled and put in our 53. Check it out on the link at the bottom, Coach Frank
