Caulking near you

Buildings are designed to let some water out, and sealing those exits turns a drainage detail into a reservoir. The classic mistakes are caulking the weep holes at the bottom of a brick veneer wall, sealing the drainage gaps at the bottom edge of siding or a window's sill, and running a continuous bead along the top of a piece of flashing so water that gets behind it can no longer escape.

The rule of thumb professionals use is to seal where air moves and leave paths where water drains. A joint above a horizontal surface usually wants sealing; a joint below one usually wants leaving open. And there is one interior case in the same family: caulking the bottom edge of a tub surround or the gap where a shower pan meets tile can trap water inside the assembly rather than letting it find the weep path it was built with.

Removal is most of the work. The old sealant has to come out completely, not be trimmed back, because new material will only bond as well as the layer beneath it. That means a sharp removal tool, a solvent appropriate to the old product, and then cleaning and drying the substrate. In a bathroom, the surfaces should be dry and the tub ideally filled with water so the joint is at its widest when the bead is applied.

Application is a single, continuous, correctly sized bead, tooled immediately so it is pressed into contact with both faces of the joint rather than sitting on the surface. Deep gaps get backer rod first so the sealant is an hourglass shape that can stretch, not a rectangle that cannot. Then it is left alone for the cure time on the label, which for silicone in a shower is measured in hours, not minutes.

Linear feet is the unit, and removal is the multiplier. Replacing a bathroom's joints where the old silicone comes out in strips is quick; the same run where three previous owners have caulked over caulk is not. Exterior work brings ladders, staging and weather windows into the price, and multi-story window perimeters cost far more per foot than anything at ground level. Product choice matters less to the bill than the hours around it, but the right product is what decides whether you are paying for this again in two years.