Locating equipment on a flat roof
From an integrity point of view, it is far better to site equipment directly onto a finished waterproofing system, as the less interruptions or penetrations to the membranes, the less likely the system is to allow water ingress. Plant is typically supported by paving slabs with a suitable protection layer beneath.
Most Bauder warm roof systems (i.e. those using PIR insulation) are capable of supporting permanently sited plant with a weight of up to 2000 kg/m², avoiding the need for penetrations through the waterproofing.
If the plant is either too heavy for the waterproofing to support, or requires fixing down to the structure, then it will be necessary to introduce a support system that can be easily waterproofed. For example, hollow section beams should be used in preference to section beams, and the larger the section, the easier it is to waterproof. Additionally, any fixings used should be of the flush head design to allow successful waterproofing.
Another satisfactory way to provide support to plant is to cast concrete plinths, which can be waterproofed with Bauder membranes and capped with leadwork. Note the cable tray system employed in this picture, supported by proprietary freestanding adjustable feet with loose laid pieces of capsheet beneath, to provide protection to the waterproofing.
Whenever there is a requirement for regular foot traffic across a roof, for example to provide maintenance to rooftop plant or a fire escape route, it will be necessary to provide protection to the surface of the waterproofing.
It is normally sufficient to provide an extra layer of capping sheet in a contrasting colour to denote the walkway and provide sufficient protection. In cases of extreme traffic, promenade tiles can be bonded to the surface of the capping sheet using hot bitumen or a suitable cold applied adhesive.