Specifiers – specify to reduce maintenance costs!
There is one thing that can be said for certain, if shower seal installers had to pay consequential losses resulting from the use of unfit sealing products and bad practices, there would be fewer leaks, fewer installers and less pressure on property maintenance budgets!
Unfortunately, more often than not leaking seals around shower trays and baths only come to notice after property damage is done. The extent of property damage and associated cost of repairs can vary dramatically.
Under BS5385, the ledge/wall joint is considered a movement joint because it is liable to expand and contract. Therefore, two critical properties required for any ‘fit for purpose’ movement joint seal are: firstly, the ‘flexibility’ to accommodate joint movement and secondly, the ‘durability’ to withstand long term exposure in high-use modern shower environments.
For specifiers dedicated to setting a standard of workmanship that reduces potential maintenance costs, specifying the quality of shower tray/bath seal required is an absolute necessity in order to limit the impact of sub-standard products and bad installation methods. Meeting the relevant Codes of Practice really does save money!
Various types of products are promoted for sealing shower tray/wall perimeter joints such as silicone, ‘soft lip’ sealing strips and combination sealing systems that combine a sealant with a flexible up-stand or PVC trim.
Slimline shower trays are promoted without integrated up-stands in favor of more flexible retro-fit sealing solutions. Polymeric up-stand seals are now available with pre-applied isolating membranes that protect the up-stand and butyl adhesive against reactive sealants in line with BS 6213 recommendations.
In the tile sector, many retailers still promote ‘soft lip’ sealing strips and the concept that by fixing a PVC strip exclusively to a wall while keeping the outer soft lip leveraged against the ledge, you can provide an effective long lasting watertight seal.The reality is that these are inherently flawed products because the sealing lip is liable to lose it’s critical downward pressure against the ledge for the following reasons, (a) joint expansion – whereby under the effects of joist shrinkage or weight settlement the ledge drops down away from the soft lip, (b) stress relaxation – whereby the fresh soft lip suffers natural fatigue over time and loses the necessary elasticity required to maintain downward pressure on the ledge (c) plasticizer migration – whereby the soft lip hardens over time when exposed to the thermal fluctuations and chemicals found in the shower environment.
Shower wall panel manufacturers have taken the initiative and include a flexible, durable sealant/trim combination seal in their product offering. The trim not only incorporates a sealant bond-breaker (green line) to create a high degree of sealant flexibility but also acts as a shield that conceals the sealant from view and the deteriorating effects of the shower environment.
By specifying a standard of seal that meets their requirements, shower wall panel manufacturers not only reduce the risk of sub-standard sealing products and practices compromising their ‘package’, but increase consumer satisfaction through providing a ‘quality controlled’ end product.
Shower wall panel manufacturers have taken the initiative and offer a flexible durable movement joint seal that enhances performance and consumer satisfaction.
Silicone is the most versatile sealing method available. Suitable sealants should be mould resistant and when used over movement joints, should be applied in conjunction with a sealant bond-breaker or backing material to create a stress free sealant ‘bridge’ between the wall and ledge that can elongate without fracture or de-bonding. Sealant with a movement accommodation factor (MAF) of 25% will require an 8mm bridge for stress free stretching of 2mm. Codes of Practice recommend sealant bond-breaker or backing material to promote flexibility and prevent three side adhesion between the ledge, tile and adjacent wall which would otherwise restrict flexibility.
Patented sealing systems incorporating pre-applied sealant bond-breakers are also available for installations with tiles.
The on-site reality with sealants is that tile/ledge joints are rarely prepared with sealant bond-breakers and the aesthetic dislike for wide sealant joints prompts installers to minimize sealant visibility, this in turn reduces the sealant’s capacity to stretch and accommodate joint movement.
Alternative Codes of Practice compliant sealing systems for tiles incorporating pre-applied sealant bond-breakers are available in profile widths of 15mm, 20mm and 25mm and offer a permanent maintenance free solution to the problem of leaking seals.
Not specifying the standard of shower tray or bath seal required on a project leaves the door open for sub-standard products and practices. Rolling the dice on shower seals is a risky business, particularly if you are one of the housing associations or homeowners left paying for the consequences of product failure.