Hello!
We are installing vertical cedar cladding as part of a ventilated rainscreen on a cabin we are building. We got the cedar rough and are finishing it into shiplap. I’d like a nice tight look.

The question is — should we put a kerf on the back of the wood cladding? And if so, what is exactly the purpose?

The boards are 6″ wide and 7/8″ thick. If we should do a kerf on the back, how deep / how many? Is there a general formula for this?

I’ve heard different things about the purpose and if one should include it or not.

Thanks!