Sealing a bathroom mirror is incredibly important, to prevent the formation of black edges and the mirror to look less appealing.
Have you been noticing black spots growing on your mirror? It can be rather unattractive and can keep you from using your mirror properly. Thankfully, there are certain steps you can take to keep them from appearing and lengthen the service life of your mirror.
In this article, we tell you why this happens, how you can prevent them from occurring, and what you can do about it if you already have a mirror with some discoloration.

Why Seal A Bathroom Mirror?
Bathroom mirrors are constantly exposed to a lot of moisture and water. When the water penetrates the underside of the mirror, it leads to the formation of black edges and makes the mirror look less appealing. To prevent this from happening and prolong the life of your mirror, sealing its edges is incredibly important.
The edges of a mirror can undergo corrosion in a high-moisture environment. Given how bathroom mirrors are prone to moisture and humidity most of the time, it is crucial to completely seal their edges and prevent moisture from getting in.
There are many mirror-edge sealing products available that are specifically designed to deal with the problem of black edges and edge delamination. Besides using such products, regular cleaning of the mirrors with the correct products and drying them after is also vital.
What Is Black Edge / Edge Delamination?
When you don’t seal the edges of your mirror, you’ll soon notice that the edges start getting black spots all over it. The mirror becomes less functional and can even look “dirty” with all the unsightly black stains over the surface.
Why does this happen?
The formation of black edges is a common phenomenon for bathroom mirrors. It happens as a result of the de-silvering of the mirror.
When water penetrates the edges or corners of a mirror, the mirror forms black spots and discoloration around its borders. Repetitive exposure to moisture or humidity is a major cause of black edge or edge delamination. Over time, this can happen to even the most well-cared for mirrors.
To understand why the edges of a mirror turn black in more detail, let us understand the chemistry between mirrors and the formation of black edges.
A thin layer of silver nitrate is applied to mirrors to prevent light from passing through and allow them to properly create reflections. An additional protective layer is applied on top of the nitrate to protect the mirror from any kind of damage. When this layer gets worn with use and different contaminants in the air, the silver nitrate layer is exposed leading to discoloration and the development of black edges or spots.
How To Prevent Black Edges on Bathroom Mirrors?
To prolong the life of your bathroom mirror and keep it looking new for as long as possible, you’ll want to keep the following tips in mind:
- Reduce humidity levels and limit the moisture content around the mirrors. Water is the primary cause of black edges. The further moisture travels into the mirror, the worse black edges get. This is why mirrors that are hung in washrooms are usually the first to develop black spots.
- Use adhesive spray paint on the mirrors’ edges.
Spray paint comes in handy when you want to prevent the mirror from getting discolored. It not just adds life to a dull-looking mirror but also prevents the nitrated layer from becoming exposed.
- Cover the edges with aluminum foil.
If you only have a few tiny black spots that have started showing up along the edges, you can cover them up with small pieces of aluminum foil.
- Build a frame around the mirror.
Adding a frame around the mirror can help prevent and hide black edges and de-silvering on a mirror. This is one of the most convenient and cost-effective options that protect the mirror from damage while adding a new and exciting look to it.
The best part is you have so many options to choose from. Pick the right frame that matches the aesthetics of your home and gives your mirror a polished and more stylish look.
How To Restore A Desilvered Mirror?
If black spots have already started to form on your mirror’s surface and the de-silvering is well underway, here are a few things you can do:
Consider It an Antique and Go With It
Desilvered mirrors have a rustic and vintage feel to them. If the antique look of the mirror is aligned with the theme of your house, you can use it as a unique decorative element.
Add A Frame
Since the black spots usually appear around the edges, you can add a frame around the mirror that covers the edges and hides the blemishes. This will give your old mirror a fresh and exciting look.
Re-silver the Spots Away
Use a re-silvering spray to hide the black spots around the edges. If you find the process too complex and time-consuming, you can always get it done by a professional.
Replace It
If the mirror isn’t an heirloom that’s been passed down by your ancestors and doesn’t hold much sentimental value, just replace it. However, make sure to seal the edges after installation to make it last longer.
What Do You Use To Seal A Mirror?
You can seal the edges of your mirror with a top-grade mirror edge sealant from your local hardware store. It protects the edges from those unattractive dark spots that occur due to moisture, mishandling, or humidity.
Mirror edge sealants are water-proof, resistant to heat and harmful UV rays, anti-fungal, and easily blend into the substrate. They are easy to use, 100% effective in sealing mirrors, and can be used to repair any cracks or cuts in the mirror.
How does it work? A coat of sealant along the edges acts as a barrier between the mirror and dust, moisture, and other damages that can affect your mirror’s appearance. When you seal the edges, you can ensure that the metal coating on the mirror will not tarnish easily and will protect the mirror from discoloration.
Final Words
We use our bathroom mirrors a lot. While they will inevitably deteriorate with time, there are still steps we can take to minimize black spots and prevent them from happening for as long as possible.
Mirrors in our bathrooms are particularly susceptible to damage due to the humidity and moisture in the air so make sure to seal the edges whenever you install a new one.
By using mirror edge sealing products, you can keep water from penetrating the edges, protect mirrors from blemishes and further deterioration, and prolong their longevity.