Sika-Trocal roofing systems are suitable for a variety of visual roof designs, including barrel vaulted, curved, double curved and domed. When designing roofs where aesthetics will be an important part of the finish, we recommend early involvement of your local Area Technical Manager. Through our experience we can assist with consideration of installation layout that can complement the design.

For example, Sika-Trocal SE decorative profiles that can be welded onto the membrane after installation to create the appearance of a raised seam. Butt joints in external Sika-Trocal Metal can be positioning to compliment the design and the layout and positioned of the sheets, can also have a dramatic effect.

Internally, it should be noted that when using a mechanically fastened system with a metal and timber deck, the mechanical fasteners securing the roof insulation and membrane will penetrate the deck and protrude from the underside by at least 15mm. This is necessary for the correct functioning and performance of the fasteners and, under no circumstances should the fasteners be shortened or cropped after installation, as it could lead to failure of the fixing system.

In these applications the use of a single fastener and disc to attach the Sika-Trocal membrane, provides a positive advantage compared to other mechanically fastened systems that utilise separate fasteners for insulation and membrane attachment.

In the case of metal decking, all of the membrane restraint fasteners will be located in the crown of the profile which is recessed when viewed from below and helps to make them less obvious. With metal decking account should also be taken of the ‘lap stitching’, which is a row of screws installed along each side lap and is at the lowest point and hence most visible, of the deck. On most projects these protruding fasteners do not cause any concern, but in the event of a painted finish to the soffit or heights being low, consideration should be given to the level of visual intrusion of the fasteners.

It might be worth considering a false ceiling or some other method of making them less visible. In some cases and in suitable locations, it might be worth considering a build-up of adhered insulation and membrane, in order to omit the fasteners, although it should be noted that the lap stitching of the deck would still be present.


Consideration should be given as to whether the roof needs to have any acoustic properties.

There are a variety of methods of controlling acoustic performance/sound transmission at roof level, that can be included within a Sika-Trocal roof construction, including;

  • The use of mineral fibre roof insulation
  • The addition of heavily filled sound deadening polymeric layers of membrane at deck level.
  • The provision of acoustically attenuated suspended ceilings below the deck.
  • The use of ballasted roof finishes and/or use of heavyweight concrete decks.
  • Combinations of one or more of the above.

Acoustics is an extremely complicated and specialist subject and expert advice should be sought for all applications. It is also advisable to liaise with all parties concerned within the construction process to ascertain that any proposed ‘acoustic solution’ is actually buildable and that suitable materials have been selected.