WARM ROOFS

As the level of insulation values, air tightness and avoidance of cold bridging has been introduced into the Building Regulations and the need for energy efficient buildings has grown, the Warm Roof has increased in popularity.  There are a number of systems which provide varying advantages to the roof construction.  In essence, a Warm Roof provides better energy conservation and fulfils all the requirements of Building Regulations and in particular systems that avoid cold bridging with the high level of heat loss that this causes.

The FOAMGLAS® Standing Seam Roof System

This comprises of a block of FOAMGLAS® Cellular Glass Insulation which is bonded with a cold adhesive to the timber, metal or concrete deck. The insulation itself is impervious to water and water vapour and ensures that interstitial condensation will not occur.

The system has zero cold bridging without through-fixing.  A metal plate is adhered to the surface of the FOAMGLAS® and covered with a bitumen membrane; this provides high resistance to the metal plates in respect of wind uplift and enables early weatherproofing of the building envelope allowing the main contractor to continue with other installations.

The hard metal sheet in copper, zinc, stainless steel or aluminium is then installed over the FOAMGLAS® system using a geotextile membrane as recommended by the metal manufacturer; the mechanical fasteners from the fixing cleat pass into the FOAMGLAS® metal plate and cause no cold bridge.

The FOAMGLAS® system provides and protects the building elements from deterioration from condensation, maintaining a high level of insulation and resistance to heat loss during the lifetime of the building.  The system provides the same life span as the outer metal sheet and, in addition, exceptionally high fire safety.

 1a       Substrate: concrete/steel deck/timber
3          Bonding with hot bitumen or bitumen cold bonding
4          FOAMGLAS® slabs / ReadyBoard
5          Serrated plates in bitumen coating
6          Torch-on bitumen membrane
7          Standing seam clips
8          Metal cladding – copper, zinc, stainless steel

Polyurethane/Polyisocyanurate with timber inserts
This system is installed over the deck with mechanical fasteners passing through the timber inserts and a vapour barrier to the structural deck.  Each of these mechanical fasteners must be calculated as a cold bridge in the construction. A separating layer is then applied followed by the hard metal outer sheet. In addition to its cold bridge situation the system provides poor fire safety, relies on a vapour barrier which is punctured by many mechanical fasteners and will suffer from the risk of interstitial condensation.
Composite Panel
Polyurethane / Polyisocyanurate foam filled metal faced panels can be installed to the structure and the hard metal standing seam screw fixed into the outer sheet. This system does not require a vapour barrier because the panel itself provides a reasonable resistance to the passage of water vapour. The core of the insulated panel is combustible and therefore the fire risk must be evaluated dependent on the use of the building.  It has the advantage of early weather proofing to the structure but will devalue in its insulation performance over a period of time due to migration of the blowing agent, normally pentane, from the plastic cells being replaced by outside atmosphere which contains water vapour.

FOAMGLAS® takes the warm roof into the future.
A long life solution, a system that is air tight and without cold bridges, totally impervious to water and water vapour and a fire safe construction because of the non-combustibility of FOAMGLAS® Cellular glass insulation. The early weather proofing of the building provides contractual economies.