Table of Contents
The short answer
Clean a joint when it is sound and only its colour is wrong. Redo it when material is missing, loose or cracked, or when the stain is inside the material and not on it. Grout that is hard, level with the tile edges and merely grey usually comes back several shades with the right cleaner and a brush. Grout that crumbles under a key, has gaps, or sits beside a tile that sounds hollow needs raking out and replacing. Silicone with black marks inside the bead, or with an edge that has lifted, cannot be rescued at all. It is cut out and a new bead is applied.
The reason to act is water, not appearance. Joints are the weak points of a tiled wet area. Once they let water through, it sits behind the tiles, loosens them and shows up as damp on the far side of the wall.
IHR Dream Cleaning does both halves of this work: tile and grout scrubbing as part of a clean, and regrouting and re-siliconing through our grout and silicone repair service, which is quoted by the area and its condition before work starts. This guide shows how to tell which one a joint needs.
Grout and silicone do different jobs
Grout fills the joints between tiles on one flat surface. Most of it is cement-based: cement, fine sand and pigment, mixed with water and pressed into the gap. It sets hard, supports the tile edges and keeps dirt out. It is porous, so it takes up water and whatever the water carries, and it cannot stretch. In a properly built shower the waterproofing is a layer underneath the tiles. Grout slows water down. It does not stop it.
Silicone sealant is a rubbery bead that grips both sides of a joint and stretches when they move. It belongs wherever two planes or two different materials meet, because those shift against each other a little every day as they warm, cool and take weight. A rigid filler cracks there within months.
| Joint | Right material | Why |
|---|---|---|
| Between tiles on a wall or floor | Grout | One flat surface with no movement |
| Wall to floor, and corners of a shower | Silicone | Two planes that move differently |
| Bath or shower tray to the tiles | Silicone | The tray flexes under weight |
| Basin, sink or worktop to the wall | Silicone | Different materials, constant splashing |
| Round a shower screen or its frame | Silicone | Glass and metal against tile |
The crack that keeps coming back in a corner
Many showers have their internal corners grouted, and a hairline crack then runs down the corner within a year or two. The grout was not badly applied. It is the wrong material for a joint that moves. Regrouting that corner buys a few months. Raking it out and running silicone in a matching colour fixes it.
Staining or failure: how to tell
Five quick tests sort most joints, using nothing more than a brush, a key, a knuckle and a cloth. Do them in good light, on a dry surface.
- Clean one short length properly. Use an alkaline tile cleaner, leave it a few minutes, scrub with a stiff nylon brush and rinse. If that length dries clearly lighter than its neighbours, you are looking at dirt, and the rest will follow.
- Draw a key along the joint with light pressure. Sound grout is hard and the key skates over it. Failed grout scores easily, and sand or powder comes out.
- Tap the tiles either side with a knuckle or a coin. A dull, solid knock is good. A hollow, rattling note means the tile has come away from the surface behind it.
- Wipe a black mark on the silicone with a cloth and a mould cleaner. A mark on the surface goes. A mark inside the bead stays, slightly blurred, like ink under glass.
- Press along the silicone with a fingertip. It should be firm and stuck fast at both edges. An edge that lifts, a gap a card slides into, or a bead that has hardened and split has stopped sealing.
| What you find | What it means | What to do |
|---|---|---|
| Grout dark, but hard and level | Dirt in the surface | Clean |
| Grout still dark after proper cleaning | Stain through the joint | Regrout, recolour or accept |
| Grout powdery, pitted or sunk below the tile | Worn out, often by acid cleaners | Regrout |
| Cracks, holes or missing lengths | Water has a way in | Regrout soon |
| Crack running down a corner | Rigid grout in a moving joint | Rake out and silicone |
| Hollow-sounding or loose tile | The tile has lost its bond | Re-fix the tile, then grout |
| Black inside the silicone | Mould in the sealant | Replace the bead |
| Silicone lifting, split or gapped | The seal has failed | Replace the bead |
| Damp beyond the bathroom wall | Water already behind the tiles | Stop and have it checked |
What is normal, and not a fault
Unsealed cement grout darkens the moment it gets wet and lightens as it dries. That is porosity, not failure. Slight differences in shade from wall to wall are common where the grout was mixed in more than one batch. A white crust on the surface of a joint is usually limescale from hard water. A white powder that keeps growing out of the joint itself is different. It suggests water moving through from behind, and it belongs with the last row of the table.
What cleaning can do, and where it stops
Cleaning takes off what sits on and in the top of the joint: soap film, body oils, kitchen grease, the grey that mop water leaves in floor grout, surface mould and limescale. On sound grout the change is often dramatic. The products and the order of work are set out in bathroom deep cleaning: limescale, grout and mould, so they are not repeated here.
Cleaning cannot put material back, close a crack, re-stick a tile or reach mould inside silicone. It also has a point of diminishing returns. Grout that is still dark after an alkaline cleaner, a brush and a rinse will not respond to harder scrubbing, and reaching for acid or a wire brush at that stage removes grout along with the stain. Our kitchen cleaning page says the same of the wall behind a hob: badly stained grout lightens but may not return to white.
If you cannot tell what you have, have it cleaned once and judge what is left. Tile and grout scrubbing is part of our deep cleaning, which starts at 2 cleaners for 3 hours each, AED 210 with our materials. For floors alone, floor and tile cleaning is booked by the hour from the same price list, and three hours of one cleaner with materials is AED 105. Whatever is still dark, cracked or black once the surface is clean and dry is the repair list.
Regrouting: what the work involves
Regrouting replaces the grout and leaves the tiles where they are. It is slow, dusty, careful work, and most of the result is decided before any new grout is mixed.
- Rake out the old grout. A carbide grout rake, or an oscillating tool with a grout blade, cuts it out to a real depth along every joint. A skim of new grout over old has nothing to grip and flakes off within months.
- Protect the tile edges and whatever lies behind them. Glazed edges chip, and in a shower the blade must not cut into the waterproofing behind the joint.
- Vacuum the joints and wash the dust away. Loose dust between old and new grout is a layer of weakness.
- Let the joints dry. For cement grout in a hot, dry room they are then dampened lightly, so that the mix does not lose its water too fast.
- Mix the grout as its maker directs and work it in with a rubber float, diagonally across the joints and under pressure, so each joint is filled to its full depth.
- Wipe off the surplus with a damp sponge once the grout has firmed, shape the joints, and polish the dry haze from the tiles.
- Renew the silicone in the corners and round the tray or bath once the grout has set.
- Keep the area dry for the curing time of the product. A penetrating sealer, if one is used on cement grout, goes on after the grout has cured and not the same day.
Cement or epoxy grout
The choice is between a grout that is easy to apply and one that is easy to live with.
| Point | Cement grout | Epoxy grout |
|---|---|---|
| What it is | Cement, sand and pigment mixed with water | Resin and hardener mixed on site |
| Water and stains | Porous; absorbs both unless sealed | Close to non-absorbent; resists both |
| Cleaning | Alkaline cleaners; acids wear it away | Tolerates most household cleaners |
| Application | Forgiving, with a long working time | Sets fast; residue must come off at once |
| Cost | Lower | Higher, for material and labour |
| Suits | Dry walls, most floors, large areas | Shower floors, splashbacks, hard-used kitchens |
Which to ask for
Epoxy is worth asking about for the floor and lower walls of a shower that is used several times a day, and for the wall behind a cooker. Its drawbacks are the cost, a slightly glossier look, and the fact that residue left on the tiles sets as hard as the grout. Cement grout, properly cured and then sealed, remains a sound choice for most of a home. Say which you want priced, or ask for both.
Colour matching, and why patches show
New grout almost never matches old grout, even from the same product in the same colour. The old joints have years of cleaning, hard water and wear in them, and fresh grout dries lighter than it looks when wet. A patch of three or four joints in the middle of a wall shows as a brighter square. The usual answer is to regrout to natural boundaries: one whole wall, the whole shower floor, or everything inside the enclosure.
Choose the colour with upkeep in mind. White on a floor is the hardest shade to keep, and a mid-grey or a tone close to the tile hides both dirt and small differences. Ask to see the colour dry before the whole area is done. Where grout is sound but permanently stained, a grout colourant, a coating made to recolour and seal the surface of the joint, is a cheaper alternative worth asking about. It does nothing for grout that is cracked or missing.
Loose and hollow tiles
Grout cannot hold a tile on a wall. A tile that sounds hollow across most of its face, moves under your hand or stands proud of its neighbours has lost its bond, and new grout around it will crack again as it shifts. It has to be lifted, the old adhesive cleaned off and the tile bedded again, or replaced if it breaks on the way off. Keep any spare tiles from the original job and mention them when you book. If many tiles in one area are hollow, ask why before they are re-fixed, because the cause may be water behind the wall.
Silicone: why it is cut out and never topped up
Bathroom silicone contains a mould inhibitor. It protects the bead for a time and is then used up. Mould takes hold on the surface, where it wipes off, and then grows into the body of the sealant, where nothing reaches it. Bleach lightens the marks for a few weeks and they return. Our published guidance is that bathroom silicone usually needs redoing every one to two years in a humid home, and that black lines which no longer scrub off are the sign.
The other failure is mechanical. With age the bead shrinks, hardens and lets go of one edge, usually the lower one, where water sits. From that day the joint is a funnel and not a seal.
Why new silicone is never applied over old
It is the commonest shortcut, and it fails for three reasons. Fresh silicone does not bond properly to cured silicone, so the new bead peels. The mould in the old bead is sealed in and shows through again. And a double-thickness bead forms a ledge that holds water against the wall. The old sealant has to come out completely, including the thin film it leaves on the tile and the tray, before anything new goes on.
How a joint is resealed
- Cut along both edges of the old bead and pull it out in lengths.
- Remove the residue. The film left behind is scraped off or lifted with a silicone remover, with care on acrylic trays and plated fittings, which scratch.
- Clean the joint, treat any mould on the surfaces behind the old bead, and rinse.
- Dry the joint completely. This step decides how long the work lasts. Sealant applied over a damp joint does not stick, and the damp it traps feeds the next mould.
- Apply a sanitary silicone, made for wet rooms, in one continuous run, and tool it into a smooth concave bead that presses onto both surfaces and sheds water.
- Leave it to cure with no water on it.
Details that decide whether it lasts
- The product. Sanitary silicone is for wet joints. Painter's acrylic filler is easier to smooth and can be painted, but it is not made for standing water and breaks down in a shower.
- The bath. An acrylic or steel bath drops slightly when it is full. Many fitters fill it before sealing and leave it full while the sealant cures, so the joint is sealed at its widest.
- The size of the bead. It has to bridge the gap and grip both sides. A thick, wide smear holds water and collects dirt.
- The gap. A joint that has opened wide, or a tray that moves when you step on it, needs fixing first. Sealant alone will tear again.
- The colour. White is standard, clear shows everything behind it, and coloured silicones exist to match grey or beige grout.
When water has already got behind the tiles
Failed joints are usually caught while the damage is still only in the joint. These signs say it has gone further.
- A damp patch, bubbling paint or a tide mark on the wall of the next room, at the height of the bath or shower.
- A stain on the ceiling of the room below, or a neighbour reporting one.
- A musty smell that stays although the room is clean and aired.
- Several hollow tiles together, or grout that stays dark low down on the wall long after the rest has dried.
- A swollen or stained vanity unit, door frame or skirting beside the shower.
Joint or pipe: which is it?
The timing usually tells you. Damp that grows after showers and fades when the bathroom is unused for a few days points to water getting through the joints. Damp that grows whether or not anyone showers points to a pipe under pressure, which is plumbing. The signs, and how a leak is traced, are in hidden water leaks: signs to look for. Tell us what you have seen when you book, so that the right trade looks at it first.
Either way, stop using that shower until it has been looked at, and do not seal over the symptom. New silicone on a wall that is wet inside traps the water there. The wall has to dry before the joints are renewed, and before any stained ceiling or peeling paint is repaired. In a rented home, tell the landlord or the agent at this stage, because what lies behind the tiles is part of the building.
Do it yourself or have it done
Resealing one short, straight joint, such as the back of a basin, is within reach of a careful person with a sharp blade, the right sealant and patience. The work is all preparation. The mistakes that send people back to do it twice are applying over the old bead, sealing a joint that is not fully dry, choosing the wrong product, and using the shower before the sealant has cured.
Have it done for a whole bath or shower enclosure, for any regrouting beyond a few joints, for natural stone, and whenever a tile is loose or a wall is damp. Raking out the grout of a shower by hand is hours of dusty work, and a power tool in unpractised hands chips tile edges that cannot be repaired. Whoever does the work, never mix a mould cleaner that contains bleach with an acid descaler, and keep the room ventilated while solvents and sealants are in use.
What a repair visit involves
Most grout and silicone jobs can be quoted from photographs, and how to get an accurate repair quote explains how to take them. These are the details that matter for this work.
- Which rooms and which joints: bath, shower tray, corners, basin, worktop, wall or floor grout.
- The rough length of sealant, the size of any area to be regrouted, and the tile size.
- Close photos of the worst joints and one wide photo of each area.
- What the tiles are: ceramic, porcelain, marble or another stone.
- Any loose or hollow tiles, any damp beyond the bathroom, and whether you have spare tiles.
- The grout colour you want, and whether you would like epoxy priced.
- Whether the home is rented, and whether another bathroom can be used meanwhile.
Before and on the day
Do not use the shower, bath or basin for a few hours before the visit, and longer if you can. Clear bottles, mats and shelves from the area, and leave the extractor running or the door open. The work needs the area dry and well ventilated, and it needs that fitting out of use until the new material has cured. At the end the technician shows you the new joints and tells you how many hours to keep water off them. Look along each bead for an even shape with no gaps at the ends, and across the tiles for haze or smears.
How long the bathroom is out of use
It depends on the product, so the figure that counts is the one the technician gives you on the day. As a general guide, sanitary silicone is usually left for about a day before it meets water. Cement grout commonly needs a day or more before a shower is used and longer to reach full strength, and epoxy grout follows its own data sheet. Plan the work for a day when another bathroom is free or the household is out. Using the shower early is the surest way to waste the visit.
Repair and deep clean: which comes first
If you already know the joints have failed, do the repair first, let it cure, and clean afterwards. Raking out grout makes dust, and the clean then removes it and leaves the whole room finished. That is why our service page pairs the repair with a deep clean or with preparing a home to move into. If you are not sure whether the joints are stained or failed, clean first and decide from what is left. Say that both are wanted when you book, so that the two visits are put in the right order with curing time between them.
Cost and payment
We do not publish a price for grout and silicone work, because a metre of sealant behind a basin and the full regrout of a shower are different jobs. It is quoted by the area and its condition, from your photos or after a free inspection, and agreed before work starts. Every quote includes VAT. Payment is online by card, from My bookings on this website once the price is confirmed.
Making new joints last
New joints fail for the same reasons the old ones did, so habits matter more than products. Abu Dhabi bathrooms are hard on joints. Many have no window, the floor is washed down to a drain, a hand spray wets the wall beside the toilet every day, and hard water leaves scale that tempts people to reach for acid.
- Dry the room. Run the extractor during a shower and for a while afterwards, and leave the door open.
- Pull water off the tiles and the silicone with a squeegee after the last shower of the day.
- Keep bottles off the tray edge and the bath rim, where water pools against the bead.
- Clean grout with a neutral or alkaline cleaner and a nylon brush. Keep acid descalers for scale, use them briefly and rinse at once.
- Rinse away soap and shampoo, which feed the film that mould grows on.
- Before long summer travel, leave the bathroom dry and its door open.
Common questions
Can new grout go over the old grout?
Not as a repair. A thin layer spread over existing grout has no depth to key into and no clean surface to bond to, and it lifts in flakes once the shower is back in use. The old grout has to be raked out along the joint first. The one exception is a pinhole or a short gap in otherwise sound grout, where the hole itself gives the new material something to fill.
How long does the work take?
Resealing a bath or a shower tray is usually a short job, most of it preparation and drying. Regrouting a shower enclosure commonly takes the better part of a day, and the floor and walls of a whole bathroom longer. Ask for the expected time when your quote is confirmed. Add the curing time on top, because the fitting cannot be used until the technician says so.
The silicone was replaced and went black again within months. Why?
Usually for one of four reasons. The new bead went over old residue or a joint that was still damp. The product was not a sanitary silicone. The room stays wet for hours after every shower because the extractor is weak or never runs. Or water is reaching the back of the bead from behind, through failed grout above it. Look at the fan and the grout before paying for the same joint a third time.
Should grout be sealed?
Cement grout in a shower, on a bathroom floor or behind a hob benefits from a penetrating sealer once it has cured. The sealer soaks in and makes the joint slower to absorb water and stains, and it is renewed from time to time, when water stops beading on the joint. It does not make grout waterproof and it does not stop mould growing on soap film. Epoxy grout needs no sealer.
The grout on my floor or balcony has cracked in a straight line. Is that the same repair?
Only if the tiles are firm. A crack that runs in a line across several joints, or through tiles as well as grout, usually follows movement in the floor beneath, and outdoor tiles also expand and shrink with the sun. Rigid grout put back into a joint that moves will crack again. Send a photo of the whole line. How each kind of floor should be cleaned once it is sound is covered in how each floor type should be cleaned.
I rent. Is black silicone my job or the landlord's?
Your tenancy contract decides, so read the maintenance clause and ask the landlord or the agent before you book. Keeping joints clean is ordinary upkeep. Renewing sealant and grout is a repair to the property, and some landlords want to approve it or arrange it themselves. It is worth settling early, because joints are among the things looked at when a home is handed back, as move-out cleaning and your deposit explains.
How to book
Book on the website or in the IHR Dream app, describe the joints using the list above and attach photos. We confirm the scope and the price before the visit. Keep the area dry for a few hours beforehand, so the work can start on a dry joint. You can cancel or move a booking free of charge up to 6 hours before the start time.
The grout and silicone repair page lists what the service covers, and the areas we serve page shows where we work. When you are ready, book a visit.
