In order to avoid problems arising on site, the location of plant on the roof needs to be agreed early in the overall program. This should include the location and means of all the service runs and subsequent roof penetrations.

Roof Mounted Equipment

Where there is a requirement to position items directly onto the surface of an exposed Sika-Trocal membrane, such as free standing handrail systems with rubberised pads, cable and trunking supports or lightweight items of mechanical plant etc, suitable measures must be taken to protect the membrane.


In these situations a patch of Sika-Trocal SBv separation layer, welded to the waterproofing membrane surface, will be required.


In the cases where small items of plant are fixed to a paving slab prior to being positioned the same requirement exists.

Penetrations

There are a number of simple principles that need to be observed to help prevent the service installation becoming a problem.


All penetrations rising vertically through the roof surface, need to be encased in Sika-Trocal Laminated Metal with a permanent cravat fixed to the penetrating item to weatherproof the gap between the two. Alternatively an upstand sleeve of rigid PVC can be installed prior to the cravat.


All services running horizontally along the roof surface that need to then pass through the roof itself, must swan neck upwards first and then pass under a cowl before being turned down through a sleeve. All services running horizontally across the roof that need to enter the building through a wall must rise up before entering the wall and also be shielded with a cowl. These requirements are to provide weathertight entry points and to prevent water running along the underside of the services and entering the building (see Sika-Trocal CAD details).


In all cases it is important to leave sufficient space around the penetration to enable the Sika-Trocal Licensed Contractor to install the waterproofing and seal the penetration.

Plant Location

The most practical and trouble free way to locate items of plant on to a roof is to put some stub columns through the waterproofing with a grillage of steelwork fixed to the top, so as to provide a fixing base for the plant. The grillage also leaves the membrane visible and accessible, thus avoiding the need to de-commission and lift plant should access ever be required.


This avoids all the pitfalls of trying to locate items of plant onto plinths that are notoriously difficult to waterproof successfully. Note that Sika-Trocal membranes are not suitable for task of waterproofing the upper surface of plinths.