Caulking can usually be found at seams of two materials, in corners, baseboards, doors and around the bathtub or surround. In order to recaulk an existing seam or caulk a new seam the area needs to be clean of debris. In other words if you plan to recaulk your tub surround then you will need to remove the existing caulk. If you purchased the Pro Caulk system found on this page then you will have an old caulk removal tool, otherwise you will use a large flat screwdriver and a hammer to chisel and scrape it out. If you are using this method then you need to take care not to damage the joining substrates by scratching them or chipping the tub or tile surfaces. Usually if you get a piece of the caulk free you can grab it with a pair of pliers and pull it like a rope the entire distance of the wall or perhaps the whole surround. Be careful with old or loose tile as removing the caulk may cause the tile to pull from the wall, breaking in the bottom of the tub. Sometimes its a good idea to run painter’s blue tape around the bottom tiles of the surround to hold them in place and place an old blanket in the bottom of the tub to prevent breakage of anything that does fall from the wall and also to prevent your tools from scratching existing surfaces.
Likewise you can also tape the top of the tub surface about a quarter inch away from the wall to help protect the tub in case your screwdriver or chisel slips. Once the old caulk has been removed, take a green scrub pad or stiff brush with or without soap and water and clean the surfaces of the seams until they are smooth, in the case of two wood substrates like doors, cabinets, baseboards use fine sandpaper to smooth the area to be caulked, however do not go beyond the area that the caulk will cover. A good caulk bead is usually 1/8″ to 1/4″. If the area that you are caulking appears to be much larger than 1/4″ you may need to fill the gap with expanding foam or repair the substrate first. If you use spray foam, let it dry then cut or sand the excess so that there is room to apply the caulk for a good cosmetic and moisture proof seal. When using any of these methods it is important to wear gloves, protective clothing and goggles and also to maintain ventilation if you are working in a closed room.
The next step after removing the old caulk and cleaning the area is to apply new caulk. A minor note, the material in grout lines is not caulk and caulk will not adhere to or replace grout. Likewise it is better to replace a tile or a soap dish with a proper ceramic adhesive or mortar. Caulk will not permanently adhere objects of any significant weight to a wall or ceiling. It is best to consult with a local ceramic tile dealer for instructions concerning these and larger repairs.
Now as with most construction compounds there is a huge amount of information and technical data as to which caulk to use for any conceivable application. For general home use there are three basic types silicone, acrylic and latex based. Latex caulk comes in white as well as an array of pastel colors. Silicone caulk can usually be found in white, black and clear and Acrylic caulk is generally white. Even though caulk can be painted it’s best to just get it in the right color to begin with.
Silicone caulk is the best for outdoor applications, but can be used anywhere. It is the most waterproof, but unless you are buying the Pro Caulk tools, it will be the most difficult to work with especially for tub surrounds. Latex based caulk is widely used for most indoor applications and it will be the easiest to work with and cleanup.
Once opened Caulk does not keep for more than a couple weeks so be sure to get the right amount. The tube will tell you the coverage. Caulk is available in a squeeze tube or a cartridge that fits into a caulk gun. Choose whichever you feel will be easier to use. Of course if you have a considerable amount of caulking to be done, cartridges and a gun will be more economical and quicker to use.
Cut the top of the tube about a quarter inch down at about a 45 degree slant. For cartridges you will need to puncture the cartridge with a wire or long screwdriver or sometimes the caulk gun has a plunger to do this. Put the cartridge in the gun and squeeze the handle until the caulk starts to come out. Push the button on the back of the gun to release the tension on the cartridge, that way the caulk doesn’t run all over the place.
It is a good idea to have a damp towel and you will also need a small bucket of water and a sponge. Use the kind of sponge that you would wash a car with, big oval, not a kitchen sponge. Take a razor blade or scissors and cut about a 3 inch piece off the sponge – you will use the smooth side of the smaller piece..
Start at one side and squeeze the gun or tube until the caulk starts to come out. Put the end of the tube directly on the surface to be caulked and pull it towards you as the caulk comes out of the tube. Caulk no more than twenty feet at a time. Before you proceed to the next area you will need to fix the caulk line. At this point if you have the Pro Caulk tools you can use them to clean up your lines. If not the you will use your finger.to smooth the lines. Put your index finger against both the wall and the tub, or touching both the horizontal and vertical surfaces whatever they might be and pull the excess caulk towards you. You can either apply the excess caulk on your finger to another place or wipe it on a paper towel for disposal.
Next take the sponge and slightly wet it. Wipe the sponge lightly over the bead, until the bead is defined as desired. If you are using silicone caulk you will have one shot to wipe, and please note the silicone will dry very fast as compared to latex caulk. Latex Caulk can be cleaned up with soap and water, whereas silicone caulks break down faster with paint thinner or higher solvents. It is best to clean your tools outside or in a well ventilated area. Let the caulk dry for at least a day and then polish off any film around the caulk line with a dry soft towel. If your project was outside check your lines for gaps or shrinking and re-apply where necessary.