Abstract: A thimble that extends through an opening is a structural element comprising: a hollow body sized and shaped to extend through the opening; an exterior seal substantially extending around an exterior portion of the body that has a selected size and shape prior to installation through the opening and a different size and shape at a time after installation through the opening to substantially seal at least a portion of the opening against passage of moisture and/or ambient air between the opening and the hollow body; an anchor on one end portion of the hollow body to substantially fix one end portion of the hollow body to the element; and an interior seal sized and shaped to sealingly engage a throughpiece extending through the hollow body to seal at least a portion of the throughpiece to the hollow body against passage of moisture and/or ambient air between the throughpiece and the hollow body.