I am in the process of installing a patio on the side of my house. I feel like I have done enough research to feel comfortable with the soil prep, base layer, sand, paver, edging, etc. My concern is drainage. The soil where the patio will be is entirely red clay. If I excavate the area and install the gravel baselayer, I feel like I am creating one big bathtub (albeit filled with gravel) that my patio will be placed on top of. Do I need to install drainage underneath the patio (i.e., in the baselayer) to alleviate this potential problem? Thanks in advance for the advice.