Most homeowners do not think about silicone until something obvious happens. A gap appears at the tub edge. The caulk turns black and stays that way no matter how much you clean it. Water sits in a place it should not.
By that point, the silicone has usually been failing for some time. The visible sign is rarely the beginning of the problem. It is the point at which the problem has become impossible to ignore.
This article gives you a reliable way to assess what you are looking at before it reaches that stage, what the different signs mean, and where each one sits on the spectrum from monitor it to replace it now.
What silicone is actually doing
The silicone seal around your tub, shower base, and countertop edges is not decorative. It is the barrier between a wet surface and the structural materials behind it. Tile, drywall, and the framing behind them were not built to be wet. Silicone is what keeps water at the surface and off everything behind it.
When that seal is intact and well-bonded, water stays where it belongs. When it is not, water finds the gap, follows the joint, and reaches whatever is behind the wall. That process is quiet. It does not announce itself with a visible drip or an obvious leak. It announces itself, eventually, with a musty smell, soft drywall, or a tile that has worked loose.
The gap between when silicone starts to fail and when that damage becomes visible can be months. In a frequently used shower in a damp climate, it can be less.
What to look for
Assessment starts with four things: colour, texture, adhesion, and continuity. You do not need any tools. You need good light and about five minutes.
Colour
Fresh silicone is white or off-white and stays that way for some time. Discolouration is not automatically a problem. Silicone that has yellowed slightly from age and cleaning products is still functioning if everything else checks out.
Black discolouration is different. Black along the surface of the silicone is mould that has developed where moisture and warmth have met. Black that runs through the silicone, visible as a dark core rather than a surface stain, means mould has penetrated the material itself. Cleaning the surface changes the appearance temporarily. It does not reach what is inside.
If the discolouration returns within days of cleaning, the mould is inside the silicone, not on it. That silicone needs to come out.
Texture
Run a fingertip along the silicone. Healthy silicone is smooth and firm but has some give. It flexes slightly under pressure and returns to its original shape.
Silicone that feels brittle, chalky, or hard has lost its elasticity. A bathroom joint moves: the tub flexes under weight, surfaces expand and contract with temperature. Silicone that has gone rigid cannot accommodate that movement. It will crack, and it will separate from the surface it is bonded to. A brittle feel is a reliable indicator that replacement is coming soon regardless of what else you observe.
Adhesion
Look at the edges where the silicone meets the tile and where it meets the tub or shower base. The silicone should be bonded continuously along both edges with no visible gap.
A gap at either edge, even a small one, is an open entry point for water. The width of the gap is less important than the fact of it. Water finds gaps. A silicone joint with any visible separation at the edge is no longer doing its job at that point.
Continuity
Look along the full length of the seal, not just the visible corners. Cracks anywhere in the body of the silicone, sections that have pulled away from the surface entirely, or areas where the silicone has thinned and receded are all failures. They may not be at the point where water is actively getting behind the tile on every shower. But they are the points where it will.
Reading where you are on the spectrum
The four signs above combine to tell you where you sit. Here is how to read that honestly.
The silicone is discoloured on the surface but cleans and stays clean for more than a week. Texture is firm but not brittle. Adhesion is continuous at both edges with no visible gaps. No cracking. This silicone has useful life remaining. Check it every few months and note whether anything changes.
Surface mould returns within days of cleaning. Texture is beginning to harden. There is minor cracking in one or two places but adhesion at the edges is still mostly intact. No gap you can see clearly but the bond does not look continuous under close inspection. This silicone is approaching failure. Replacing it now is cheaper and simpler than addressing the moisture damage that follows if you wait.
Black mould has penetrated the silicone itself and cleaning makes no lasting difference. There is a visible gap at either edge. The silicone is brittle or has cracked through in any section. Sections have pulled away from the surface entirely. Any of these individually warrants immediate replacement. More than one means the seal has likely been compromised long enough that the joint and the area behind it need to be assessed carefully before new silicone goes in.
What does not work
- Applying new silicone over old silicone is the most common mistake. The new material bonds to the old surface, not to the tile and tub underneath. The adhesion is compromised from the first day, and any mould inside the old silicone continues developing underneath the new layer. The joint may look clean for a few weeks. It will not hold.
- Bleach on black silicone whitens the surface. It does not reach mould that has developed inside the material. The discolouration returns because the source has not been addressed.
- Grout, epoxy filler, and caulk tape are not substitutes for silicone at a bathroom joint. The joint between a tub and tile moves. Materials that do not flex will crack. They are also not waterproof in the way that correctly applied silicone is.
How long silicone should actually last
The honest answer is that it depends on three things: the quality of the product used, the quality of the application, and the ventilation in the room.
Professional-grade silicone, properly applied to a clean and dry surface, should last five to ten years in a well-ventilated bathroom. In a bathroom where the fan is undersized or not functioning properly, moisture stays in the room longer after every shower and the silicone deteriorates faster. In a bathroom with adequate airflow, the same silicone may last longer.
The quality of the original application matters as much as the product. Silicone applied over residue from the previous seal, applied to a damp surface, or applied in a thin bead that does not fully cover the joint will fail significantly earlier regardless of product quality.
If your silicone is being replaced every year or two, the product or the application is the problem, or the ventilation is, or both.
What Emmassa looks for
Before any silicone comes out, the joint gets examined fully: the condition of the existing seal, what the surface behind it looks like once the old material is removed, and whether the substrate is sound enough to bond to. If the drywall behind the joint has been wet long enough to soften, new silicone will not hold properly and the drywall needs to be addressed first. That finding gets communicated before the job proceeds, not after.
The preparation is where the work actually happens. Full removal of the old silicone, surface cleaning, and full drying before any new material goes in. In a bathroom that has been damp, that drying time matters. Rushing it compromises the bond.
If the assessment finds that the problem has moved past the silicone and into the wall, Emmassa says so and does not take the job. Replacing silicone over active structural moisture damage is the wrong work done in the wrong order. The scope is clear before anything begins.
Emmassa’s silicone work carries a one-year guarantee against leakage.
