Q.Is there anything i can paint in the base of my wisteria to prevent new growth
I just put a hot tub on my back porch, theres only about 18 inches behind it,as you imagine the wisteria grows fast and wild. is there anything i paint on bases ( about 24inches up) to prevent shoots from sprouting up,and out.

There are plant growth regulators that can be used to reduce vigorous, long vertical vegetative growth and divert energies to root development. But I've never heard of them being painted on wisteria stems to suppress sprouting.
I suggest that you just adopt a weekly management task of rubbing off (pinching/breaking/pruning) the new tender sprouts that appear, before they develop into woody stems.