Caulk Removal
Summary: Removing caulk to replace it because of mold and mildew is a time consuming job. The good news is that the replacement caulk can now contain a mildewcide to kill mildew off. Some of these are colored caulks that come with lifetime guarantees.
DEAR TIM: The caulking in several places in my bathroom has mildewed. I have tried unsuccessfully to stop the mildew growth. I want to install new caulking. How do you easily remove caulking? What kind of caulk can I install that will not support the growth of mildew? Andrea Z., Hobe Sound, FL
DEAR ANDREA: Welcome to the club! Many homeowners, including myself, have battled unsightly caulk joints in bathrooms, kitchens and other high moisture locations for years. I have good news and a little bad news. You can now purchase mildew proof caulks to eliminate future mildewed caulk problems. The bad news is that it is going to take some effort on your part to remove the existing caulk. To the best of my knowledge, there are no miracle caulk removers.
Bathrooms, and kitchens are ideal locations for mildew growth. Mildew needs a moist environment and food to thrive and survive. Bathrooms - especially tub and shower areas - provide ideal growth conditions for mildew. Daily showers and baths supply water that often ponds at the locations where you frequently use caulk. These areas are often the last to dry out as the water evaporates. Body oils, soap films, shampoos, and other hair care products almost always contain ingredients that provide mildew spores a continuous, delectable smörgåsbord. Certain caulks actually contain organic ingredients that mildew eat.
Caulk removal begins by manually scrapping out the bulk of the old caulk. You can use a razor blade or any other type of cutting or scraping tool that will not hurt you or the materials adjacent or beneath the caulk. If you decide to use a razor knife of any type, I suggest you wear medium duty leather gloves to protect your hands during the removal process. Feel free to incorporate some water as a lubricant. The water will help to minimize scratches to tile or plumbing fixtures. Work slowly and carefully. Remember, the more power you exert while scraping or cutting, the more control you lose over the scrapping tool.
Once you have removed the bulk of the old caulk, you can try several off the shelf caulk removers or products you may already have in your own home. Experiment first with plain water. If the original caulk was a non-acrylic water based caulk, soaking it with water saturated rags for 3 days can soften the caulk remnants. Water based acrylic caulks and those made with polyvinyl acetate resins can often be softened by soaking them with isopropyl rubbing alcohol. The alcohol swells the old caulk molecules and helps to lift them from the surrounding materials. Be careful when using the alcohol as it is a flammable substance and often burns with little or no flame.
Silicone caulks are the hardest caulk to remove. There are not really any solvents you can buy to easily remove silicone caulk. Multiple applications of strong alkaline compounds like sodium or potassium hydroxide can soften silicone caulk. However, these chemical compounds are dangerous and can often burn you or the materials surrounding the caulk. You can try oven cleaners or strong powdered cleansers that you mix with water to a paste consistency. Apply these carefully to the caulk with a cotton swab. These compounds can dull plastic laminate tops, acrylic and fiberglass tub and shower units and many other bath and kitchen materials. You must work slowly and carefully.
Once the old caulk is removed, purchase new mildew proof caulks that are widely available. These caulks often contain vast quantities of mildewcides - chemicals that leach from the caulk over time and poison the mildew spores. Some of the caulks come in beautiful colors and offer lifetime guarantees against mildew growth.
You can minimize mildew growth in bath and shower areas by cleaning them on a frequent basis. Cleaning and rinsing all surfaces with clear water will remove mildew food sources. You should also keep tub and shower doors and curtains open after you leave a bathroom. Leave bath doors open as well to speed the drying process.
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Comments:
Ruth 29 Dec 2007, 09:49
Thank you for your detailed advice. Do I have to remove ALL caulking
before replacing it? If so, won't the tile fall or move? Most of my mildew
is on the bottom-side of tiles, between the tub and the bottom tile.
Also, in order for my shower to look uniform, I'd like to 'top off' all of my tiles with the product I'm using to replace the mildewed caulk. Do I have to do anything to treat those tiles?
AsktheBuilder 29 Dec 2007, 11:34
Ruth,
I would remove all of the caulk. The tile should not budge. If it does move, you have more serious issues!
Cory 11 Jan 2008, 17:03
Tim, Thank you for your advice. I plan to use it. Can you suggest a
mildew proof silicon caulk for my shower? Thanks in advance.
AsktheBuilder 11 Jan 2008, 18:07
Cory,
I don't believe one is made.... The caulk-manufacturer attorneys made them stop making that claim....
Robert 22 Jan 2008, 21:37
Tim - I have used caulk to fill in some of the seams on my 2 member crown
molding and unfortunately I used to much of it in a few places and need to
try and remove or redo it. Can you recommend a way to do this? I need to
remove it from the painted wall and base portion of the molding.
AsktheBuilder 23 Jan 2008, 16:17
Robert,
Adhesive remover might soften it for you.
Eric 06 Mar 2008, 16:52
"There are not really any solvents you can buy to easily remove silicone
caulk."
I'm recaulking my shower, after failure of the original caulk and a craptacular job done by a "professional" sub-contractor who simply caulked over the old bead. I found McKanica Silicone Caulk Remover gel and tested a tube. Oh my! Talk about easy! Simply squirt a good amount over the old caulk, let it sit for 2-3 hours, then scrape it off with a nylon or plastic putty knife. then wipe the area down with denatured alcohol and it's squeeeeqy clean with absolutely no caulking residue. The stuff isn't real cheap, some $4-5 for a 3oz tube. They claim it's good for approx 10' of a 1/4" bead. So I'm looking at maybe 4-5 tubes of it for my walk-in shower enclosure, maybe more. But it hasn't discolored or damaged any of my vinyl flooring, fiberglass pan, ceramic tile, or chrome door hardware. Cheap price to give me a perfect surface prep for the new caulk and the years of service that will result.
Ruthe 08 Mar 2008, 16:05
Thanks for telling what really happens when one tries to remove old caulk,
"The bad news is that it is going to take some effort on your part to
remove the existing caulk."
Ruthe
AsktheBuilder 09 Mar 2008, 14:06
Eric,
Thanks for sharing! This must be a new product out since I wrote that column. At the time I wrote it when interviewing the caulk scientists, I was shocked they didn't have a remover.
cora 01 Apr 2008, 17:21
AsktheBuilder
I work with men (who are either too nearsighted to notice, or too slobby to care)and several culprits spray/dribble urine along the front of the toilet. Not only has the smell gotten less tolerable, the caulk at the front of the stool has shriveled. It looks like I'm going to have to undertake the venture of replacing the caulk myself. :-( My questions are: 1. once I get the old caulk off, how far in/back/under do I need to clean to banish the odor? Do I need to remove the entire toilet? and 2. what caulk would you recommend I use (I've seen advice for mildew resistand caulk, but never ammonia resistant caulk)? thanx cora View all comments |


