Caulking over existing caulk can lead to mold and moisture getting trapped in the joints and if left to grow, this can cause serious structural issues in your home.
So read the whole article to understand the pro's, con's and warnings before you jump in head first and regret it later as there are situations where you should definitely not caulk over new caulk.
For the best results, we advise removing all of the old caulk from the area in question before recaulking from square one.
This will give the best seal and will help your caulking job to last a lot longer without the need for recaulking.
Read on to find out the different situations where you should and should not recaulk...
Can You Caulk Over New Caulk If the Caulk is Still Wet?
This is your best bet for caulking over new caulk. If you apply a second layer of caulk when the underlayer is still damp this will allow them to bond better.
When both layers of caulk are wet they can mix better, meaning that they can bind to one another and the surface.
Can You Caulk Over New Caulk If the Caulk has Dried?
This requires a little more preparation to pull off. This is suitable for placing new caulk over a dried area that has previously been caulked.
You should first clean the old, exposed caulk. We suggest using a toothbrush and neat bleach to scrub the old caulk. Rub off any excess and allow to dry completely.
You should rub the caulk with a clean and lint free cloth to get rid of any dust, fibres, or other debris. The presence of these will impede the caulk’s ability to stick to your surfaces.
Your surface is then ready for the new caulk to be applied. You should ensure you use the same brand of caulk as the underlayer to caulk the top coat. This ensures the best chance for the caulks to stick together and remain in place.
You should apply the second layer of caulk in a wider bead than the first. This will completely cover the first layer and should seal the exposed sides too.
If your new caulk has different ingredients, this increases the risk of the two caulk layers splitting over time.
What Are the Benefits of Caulking Over New Caulk?
This method can help you to accurately seal deep and wide cracks between tiles. These can lead to leakages and damp in your walls if left alone.
Adding a second layer on the top means that it is likely all of the cracks will be filled in.
Using the same caulk twice means that the seal is likely to be stronger and more resilient.
What Are the Downsides of Caulking Over New Caulk?
There is a high chance that the 2 caulk varieties will separate over time. This can lead to mold developing in between the layers and caulk flaking off the walls.
If you do not clean the existing caulk or remove the dust, this reduces the adhesive ability between the two layers. If you caulk over mold, then as the new layer dries out you will find the top layer flakes off with ease.
How to Do the Job Properly
The best method of recaulking will take longer but will also last longer and produce a much stronger seal.
Your first step is to remove any old caulk using a putty or utility knife, razor blade, or scraper. At the same time, scrape off any caulk or sealant residue as well as paint, dirt, and grease. And avoid caulking over grout.
Wipe the surface well to get rid of any dust or debris. We suggest using a disinfectant or rubbing alcohol to do this.
You should then rinse off any remnants using a clean damp cloth. If you see any mold at this point, use a toothbrush and neat bleach to scrub the affected area.
You should dry the surface to be caulked thoroughly, or allow it to dry completely for 24 hours. Look at the size of the gap you are caulking - if the space is wider than ½ inch we suggest pressing some foam tape into the hole to reinforce the seal.
You should then add some painter’s tape around the area you are intending to caulk. This will prevent the caulk from spreading onto your surfaces and create a much neater finish.
Grab your caulk tube or gun. Follow the manufacturer’s instructions on the outer casing to release the caulk from the tube.
We will refer to the caulk as ‘beads’ - this means the line of caulk that has been forced out of the tube.
The width of this line varies according to where you snip the nozzle. Cut it closer to the tip for a thin bead, and closer to where the caulk is stored for a wider one.
You should always cut the nozzle off at a 45 degree angle. This makes application much easier and more aesthetically appealing.
If you are using a caulk gun, insert this into the frame. Press the release at the base of the gun and extend the plunger fully.
Hold the nozzle of the caulk gun where you wish your bead to begin. Angle the caulk at 45 degrees to the surface, with the diagonal side facing the gap your caulk is going into.
Hold the gun and squeeze firmly to expel some caulk, slowly pulling the gun around the area to be caulked. Ensure the pressure remains consistent as you move the gun to keep the caulk equal and even.
You should then smooth out your caulk bead to ensure a more professional looking finish. The easiest way to do this is to gently dampen your finger and then gently but firmly run it over the freshly caulked area.
You could also use a caulk finishing tool if you have one to hand.
If you have laid down painter’s tape, you should remove this from the surface before the caulk has been allowed to set.
Use a damp cloth to wipe off any excess caulk from your surfaces. This too, should be done before the caulk is allowed to dry.
Caulk should take around 24 hours to cure completely, although we recommend checking the manufacturer’s instructions to be sure.