I recently purchased a house built in 1980. Somewhere around 2000 the bathroom was remodeled, including a one piece Lasko shower/tub. I noticed creaking and cracking noises when taking a shower. I put a camera under the tub from the basement hole near the tub drain and the unit was not set in mortar. There isn't an acess panel but there is a bedroom closet behind the long side of the tub and linen closet on the plumbing end. I was told by a local plumber to drill holes from the basement and use Great Stuff. I am not sold on that idea. Any suggestions on how to get some support under this tub? There was an older woman that owned it before me and weighed 100lb soaking wet & most likely didn't notice.