Water leaks

A leaking shower can cause substantial damage which will be expensive to repair if the problem is not rectified quickly. When a water leak in the area of the shower is identified the understandable reaction is to blame the shower enclosure, frequently this is not the case. If water cannot be seen leaking through the frame of the shower enclosure it is most likely not the cause or source of the leak. The greater occurrence of water leaks stem from issues related to silicone sealant and specifically where, how and when it is applied.

Topics Covered

Water leaks from shower trays

The majority of water leaks are associated with the silicone sealant joint between the shower tray, walls and shower enclosure. The exact location of water leaks emanating from silicone sealant joints can be difficult to detect due to capillary action. Leaking water will flow along the path of least resistance creating ‘capillary action’ caused by the adhesive properties of water. The principle of capillary action is used by shower designers to make shower enclosures water resistant.

Often water leaks appear as a puddle on the floor outside the shower, a damp patch on a wall next to the shower enclosure or a damp ceiling in a room below the bathroom.

Understandably, when a puddle of water or a damp patch develops it is often the shower enclosure which is assumed to be at fault. This is rarely the case. The two most common issues are; water leaking from behind the shower enclosure wall fixing channels, the failure of the silicone sealant joint or cracked tile grout.

Further information regarding correct application of silicone sealant is available in the How To section of Shower Advisor.


Water leaks associated with the shower tray waste

Water marks on a ceiling below a leaking shower are common and the shower waste is often suspected to be at fault. Although leaks from shower tray wastes are rare they do occur. The upper section of the shower waste is screwed into the swirl pot below the shower tray clamping the two sections together. A thick rubber gasket, and silicone sealant between the two parts of the waste, creates a water tight seal. If the tray is raised above the floor it may be possible access the waste to check for leaks. Spray the shower head around the drain and directly into it while checking for leaks. If the seal around the drain is at fault it will be necessary to remove it in order to renew the sealant between the shower tray and the grate or replace the rubber seal.




Water leaks from behind the shower enclosure wall channels

When a shower tray is installed it should be fully sealed to the tiled walls with sanitary silicone sealant. Tiling should extend to outer the edge of the shower tray so that the shower enclosure is fitted onto the tiles. A common mistake is to fit the shower enclosure directly to the wall and then apply tiles up to the inside. Before the shower enclosure may be installed the silicone seal between the tray and tiles must be in place and be fully cured, a process that takes a minimum of 24 hours. Many manufacturers will print the following statement in bold lettering at the beginning of their fitting instructions.

IMPORTANT – the shower tray must be fully sealed to the tiles and all grouting completed before installing your shower enclosure. The shower enclosure must be fitted to a tiled wall. Failure to do so may cause water to leak into the wall behind the wall channels”

Water enters the frame work of a shower enclosure when it is in use, by allowing this water to easily escape flow is created. The flow of water helps to ensure that the shower enclosure is water resistant by drawing water from the frame into the shower tray rather than trying to stop water entering the frame.

Correct installation requires the tiled walls to be sealed to the shower tray and the shower enclosure must in turn be sealed to the shower tray and walls. For the shower enclosure to drain correctly it should only be sealed to the shower tray on the outside unless the fitting instructions specifically instruct otherwise. Inside the shower enclosure silicone sealant should only be applied vertically where the wall profiles meet the tiles.

If the shower enclosure is correctly sealed water entering the frame work will flow freely from the base of the door and drain into the shower tray. The silicone sealant joint between the shower tray and tiles should extend along the full length of the tray beyond the point where the shower enclosure is fitted to the walls. If the silicone sealant joint does not continue behind the shower enclosure wall fixing profiles water entering the frame will escape from under the base of the wall fixing profile and leak through the gap between the tiles and tray.

Unfortunately extra silicone sealant is often applied to the inside of the shower enclosure at the base, where it meets the shower tray, in a misguided effort to stop the leak. Applying extra silicone sealant to the base of the shower enclosure worsens the problem by trapping water in the frame and increasing the quantity that can leak through gaps in the silicone sealant behind the wall fixing profiles.

Removing the shower door and resealing the shower tray correctly is the only way to correct the problem. Residual silicone should be removed from the shower enclosure, shower tray and tiled walls prior to refitting. Silicone can be difficult to remove and care will be required not to damage the aluminium frame of the shower enclosure. If the old silicone sealant is not removed and the area thoroughly cleaned the new silicone will not adhere properly.
Fresh silicone sealant should not be reapplied until any damp areas have dried completely; residual damp will prevent the silicone from curing. Extensive areas of damp should be exposed and may take several days to dry completely. New silicone sealant should be allowed cure for a minimum of 24 hours before the shower enclosure is refitted and the same drying period should be observed for sealant subsequently applied to the shower enclosure when it is reinstalled. New fixings for the shower enclosure should be available from the manufacturer.

Water leaks from failed silicone sealant joints

Even when silicone sealant is applied correctly between the shower tray and tiles leaks can occur. The sealant can become detached from the shower tray due to movement or even deteriorate with age.
It is not uncommon for slight settlement of the shower tray to occur over time. Settlement is caused by movement in suspended floors, the weight of the shower enclosure and that of a body may cause the tray to settle a few millimetres.

Settlement can cause the sealant joint between the tray and tiles to become detached. When the shower is unoccupied the silicone sealant may appear to be in contact with the tray and tiles, when weight is applied to the tray it compresses and a small gap of perhaps a millimetre or two can appear under the sealant allowing water to escape into the walls under showering conditions. The problem can also occur if the surface of the tiles and shower tray are not thoroughly clean before the silicone sealant is applied.

The symptoms associated with this issue are similar to those of incorrect application of silicone sealant; indications are damp patches in walls and on the floor outside the shower enclosure. It is not uncommon for the lower row of tiles to become loose or detached as water soaks into the wall and causes the adhesive to fail.

If the problem is recognised early the sealant between the tray and tiles can be replaced, although the shower enclosure will also have to be removed.  Damp areas should be dried and the sealant reapplied as previously described.

If the tray has been leaking for some time it may also be necessary to remove any loose tiles exposing the damp wall behind. Damp areas will have to be left to dry thoroughly before they are treated, retiled and finally sealed. If the wall behind the damaged tiles is very wet it may be necessary to replace the render or dry lining, often requiring the whole shower, including the tiles and shower tray to be removed. It is imperative to deal with water leaks as soon as they occur if damage and expense are to be avoided.

When sealing the shower tray and tiles to each other it is important that adequate silicone sealant is applied filling the gap between the two. The bead of silicone should be approximately 10mm thick when smoothed. If the shower tray is new, or situated on a suspended floor, weight should be placed inside the tray before applying the sealant, compressing the shower tray slightly and preventing the seal becoming detached with use. Always ensure that the surface of the shower tray and walls are clean and dry before applying silicone sealant.

Deterioration of silicone sealant

Silicone sealant will deteriorate and perish with time. A good quality sanitary silicone sealant containing mould inhibitors may last 5 years or more. When the sealant ages it loses its elasticity becoming hard and brittle which will cause it to become detached from the wall or shower tray and allow water to escape. Deteriorating sealant also can cause the outside of the shower enclosure to become detached from the shower tray and allow water to leak from under the frame and onto the floor.

The problem can only be rectified by removing the shower enclosure and cleaning away all the old silicone sealant and replacing it with new. The procedure for cleaning and applying silicone sealant is explained in detail in the How To section of Shower Advisor. 

Water leaks associated with tile grout

Water leaking through tile grout joints is a common issue often caused by movement in stud walls or deterioration of the grout due to age. When tile grout fails water seeps into the walls and the adhesive will begin to break down and fail. If the tiles are bonded to a stud wall the cladding may become damp and swell causing the tile to appear as if it is being pushed off the wall.

If cracked or deteriorated grout is identified before damp becomes an issue it can be easily removed with a removal tool and new grout applied. It is important to ensure that the wall is dry before new grout is applied and it may be necessary to leave the open grout gaps exposed for a few days to allow trapped moisture to dry. More extensive leaks and damp may require complete removal of the tiles allowing the walls behind be repaired and dried before re-tiling.