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Aquastrap is a two part sealing system that combines a flexible adhesive up-stand strip and a silicone.


It should be understood that the following ‘codes of practice’ are offered exclusively as guidance on best practice and are not specifications or requirements that must be met. The codes are voluntary. We ask you to simply consider the merit of these codes and benefit of compliance in the context of the product supplied and the task in hand.

components of aquastrap

Aquastrap comprises of:

1. EPDM up-stand
2. Up-stand isolating membrane
3. Butyl adhesive tape
4. Butyl adhesive isolating cord
5. Lower adhesive release liner
6. Upper adhesive release liner
7. Sealux-N silicone

aquastrap stuck to shower tray

  1. The primary sealing material in this two part sealing system is the silicone which is typically applied into the joint between a wall tile and adjacent ledge.
  2. The secondary sealing materials are the up-stand strip and adhesive strip. The up-stand strip forms the third inner side of this three sided sealant joint.
  3. The up-stand strip and butyl adhesive are polymeric components strategically layered with sealant isolating materials to prevent contact with reactive silicones.

Sealant Selection

BS5385-1:2009 Section 5.9.2 and BS5385-3:2007 Section-5.7.2 states joint sealants should be selected and applied in accordance with the guidance given in BS 6213.
BS5385-3:2007 Section 6.8.2 (Sealant installation) notes that sealants for movement joints are now classified by performance, at seven levels within type F of
BS EN ISO 11600:2003 and further suggests a particular chemical type of classified sealant might be selected preferentially in certain circumstances e.g. to ensure, resistance to particular chemicals, compatibility with adjacent materials, avoidance of substrate staining or severe service temperature conditions.
BS6213:2000 also refers to BS ISO 11600 (a sealant performance specification) as a means of identifying suitable sealants which meet a number of requirements, in particular movement accommodation.
Sealux recommend Sealux-N as part of the Aquastrap Sealing System. Sealux-N is a high performance neutral curing sealant that conforms to
ISO 11600 F+G-25 LM. Please refer to Technical Data Sheet for further information.

Material compatibility

BS5385-1:2009 Section 5.9.3 and BS5385-3:2007 Section 5.7.3 advises the back-up material should be compatible with the sealant being used.
BS6213:2000 Section 4.5.3 Sealant selection (Substrate compatibility) advises consideration should be given to the specific substrate compatibility and characteristics which may exist prior to sealant installation: ……(e) sealant staining or discoloration which may occur from contact with other polymeric construction components within the joint. Appropriate substrate preparation is suggested in conjunction with sealant manufacturers. The effects of specific adverse conditions such as those given in a) to f) may be reduced or overcome by careful sealant and primer selection and the specification of appropriate substrate preparation in conjunction with sealant manufacturers.

The reality is that sealants can react aggressively with polymeric joint materials such as EPDM and butyl adhesives as the adjacent photos highlight.

The butyl adhesive has changed from a strong high tack adhesive to the consistency of a creamy paste. The EPDM up-stand has deformed where it is in direct contact with the sealant.
Normally the issue of a sealant’s incompatibility with the adjacent joint substrate material is dealt with on site where the joint is formed. In the context of the Aquastrap strip, the issue is fully addressed during the manufacturing process wherein isolating materials are applied over both the EPDM up-stand and butyl adhesive.
The Aquastrap up-stand strip is supplied BS6213 compliant insofar as the polymeric up-stand and butyl adhesive materials are isolated from direct contact with reactive sealants that may later be applied into the joint between the wall tile and adjacent ledge.

NHBC Standards 2010

NHBC standards 2010 cover the issue of tiling to walls & floors under Chapter 8.2
NHBC require the design to consider and make provisions for interface joints between 2 different materials/substrates – If the interface will have movement then the provision of the joint should accommodate the expected actions and suitable materials used.
NHBC do not specify the sealant properties or even the requirement for sealant but an effective seal (which can accommodate the water resistance or performance intended) for the interface joint. This essentially leaves the requirement for the selection of suitable materials up to the designer or manufacturer.
Where applicable, the appropriate standards and codes of practices (CP’s) should be referred to. Manufacturers technical data and installation requirements can be considered acceptable for non-critical functions providing they would not compromise the requirements of the relevant CP’s or other standards that may have a greater requirement.


Further information can be got at

Aquastrap and Building Standards December 17, 2018