Homeowners
Sealant joints in bathroom and shower
Black spots along the shower corner will not come out with cleaning any more. We cut the old sealant away completely and lay a new joint, with sealant that belongs in a wet room.
Since 1959
Experience and craftsmanship from Utrecht
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Short lines, clear agreements
100% satisfaction
We only leave once you are satisfied
Lasting quality
Top-quality materials for a long-lasting result
The problem
Why the mould keeps coming back
Sealant for wet rooms contains a mould-inhibiting agent. That agent is in the sealant, not on it. It slowly comes to the surface and keeps the edge clean for years.
If you clean with chlorine, you wash that agent out. The same goes for abrasive and aggressive cleaners. The edge becomes porous and the mould comes back faster than it came the first time.
Once the mould is in the sealant, it sits deeper than a brush can reach. Bleaching takes the colour away, not the cause. Replacing it is then the only real solution.
What does help after replacement
- Clean with a mild product. No chlorine, no scouring paste.
- Wipe the walls dry with a squeegee after showering.
- Air the room. In new builds the requirement for a bathroom is 14 cubic decimetres of air per second (Bbl). If you only have a window and an extractor, leave the extractor running for a while after showering.
How we do it
Re-sealing a shower, step by step
Old sealant out completely
With a knife, right down to the flanks. New sealant does not adhere to old sealant, so a layer over the top comes loose again within a year.
Making the surface clean and dry
Residue removed, degreased, left to dry. Where the surface calls for it, a primer goes on. Moisture in the joint is the most common mistake.
Choosing the right sealant
In a wet room we use silicone or a hybrid sealant with a mould-inhibiting agent. If there is natural stone or marble, a special natural stone sealant goes in.
Applying and smoothing off
The joint is filled in one movement and smoothed off tightly. In a wide or deep joint, a backing rod goes in behind it first.
Curing
After that the sealant has to be left alone. How long exactly you can read below. At handover you get brief maintenance instructions.
Craftsmanship
Where it usually goes wrong
A sealant edge that comes loose after six months is almost never bad luck. The cause usually lies in the joint itself or in the surface. These are the four we come across most often.
What the joint should look like
Cross-section of the corner between a tiled wall and a shower tray. Between the tiles and the tray is a joint. At the top of the joint sits the sealant, finished concave; below it lies a round backing rod. On the tray stands a thin layer of water.
- The joint is at least 8 millimetres wide and 6 millimetres deep. Any narrower and the sealant cannot accommodate the movement.
- The sealant sits concave, not convex. Water then runs off instead of standing on it.
- Behind the sealant is a backing rod. That way the sealant adheres to the two sides only and not to the base, so it can stretch.
The joint is too narrow
Elastic sealant needs room to stretch. For a sanitary joint you count on at least 8 millimetres wide and 6 millimetres deep. If the joint is narrower, the sealant tears down the middle as soon as the tray or the wall works a little. Filling it up again does not solve that. The joint first has to be made wider.
There is acrylic in the shower
Acrylic is fine for sealing a gap in a wall, but it cannot cope with prolonged water. It slowly dissolves. You recognise it by a matt, chalky edge that comes loose in flakes. In a wet room, silicone or a hybrid sealant belongs. The drawback of silicone: you cannot paint over it.
The surface moves
Loose tiles, damp tiling or a shower tray that gives way when you step into it. Sealant is a sealing material, not a structural adhesive. If the tray moves, every joint you lay in it tears. If we see that, we say so. Even if that means the job waits until it has been repaired.
The wrong sealant on natural stone
Acetic-curing silicone sealant does not belong on marble, natural stone, mirrors, aluminium or zinc. On natural stone the plasticisers draw into the pores and give a dark edge along the joint. That discolouration sometimes only shows after weeks and never comes out again. Cleaning does not help.
Another one: a sealant joint may only be fixed on two sides, not three. If it also adheres to the base, the middle cannot stretch and the joint tears. That is why a backing rod goes in behind a deep joint.
Planning
Allow two days without showering
Sealant cures from the outside inwards, around 2 to 3 millimetres per 24 hours. That applies at around 20 degrees and normal humidity.
A sanitary joint is at least 6 millimetres deep. One day is therefore tight. Allow two days before you shower again.
If you go earlier, water draws into a joint that is still soft inside. That is where the problem starts again. If it is cold or the room stays damp, it takes longer.
If you have one bathroom, plan the job at the start of a weekend or arrange a shower elsewhere. We tell you in advance how long you cannot use the room, so you can plan around it.
What does it cost
Price and guarantee
We charge per job, not per hour. You hear the amount before we start. Send one photo from a distance and one from close up, and we can see the condition of the surface and the width of the joint.
You get a 2-year guarantee on the work carried out. What is and is not covered is stated in the quote. This guarantee is in addition to your statutory rights and does not limit them.
Good to know
Questions about the bathroom
Can the new sealant not simply go over the old?
No. Sealant does not adhere to sealant. The old edge has to come out right down to the flanks, otherwise the new joint is only loosely attached and comes away again within a short time. Cutting it out is the largest part of the work.
Does the whole bathroom need doing, or only the shower corner?
That depends on what you see. It often starts at the shower corner and the connection to the tray, because that is where most water comes and where most movement happens. If the rest is still tight and does not smell musty, we leave it.
There is a gap under the shower tray. Is that a problem?
That can be a sign that the tray moves or is not properly supported. The sealant is then not the cause but the victim. We look at it first before we seal anything.
Can I paint over it?
Not over silicone, and that is exactly the sealant that belongs in a shower. If paint does have to go over it, for example along a painted ceiling or window frame, we use a paintable type there.
How quickly can you come?
You hear from us within 15 minutes on working days what it costs. How quickly we can schedule it depends on the diary.
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