Vapour Closed Solutions for Solid Walls
Vapour tight systems are the most common solution used on the market today, usually in the form of thermal laminates – insulated plaster board
Considering a “non breathable” wall cannot cope naturally with the movement of water, then these 5 critical factors MUST to be present in an IWI system to make sure it’s “DESIGNED” performance is equal to it’s “INSTALLED” performance.
- Continuous Vapour Control Layer – Board Joints
- Continuous Insulation Layer – No thermal breaks
- Thermal Bridging due to multiply fixing
- Thermal Looping due an unventilated cavity
- Adequate treatment of thermal bridging – reveals, returns & floors
The key factor as the title suggests is, that the wall must be Vapour tight which simply means that the system you choose must stop hot vapour transferring from the warm side to the cold side of the insulation. Failure to address this key issue will lead to the hot vapour condensing on the cold wall and turning to water.
Over a period of time this will lead to the reduction in the performance of the insulation material but in addition the formation of mould and degradation of the fabric of the building will occur.
The second issue is that the insulation must be continuous and have no breaks. Studies have shown by the Fraunhofer Institute that, a 1mm gap in the insulation layer can lead in a drop in performance by a factor of 4.8. Therefore a system, designed to perform at 0.3 U Value, will in affect perform at 1.5 U Value.
Fixing multiple screws through the insulation layer either by a direct fixing method or screwing laminates onto timber battens is reducing the effectiveness of the insulation installed by creating a direct avenue for heat loss from the warm inside to the cold external wall.
If there is a cavity or air gap behind the thermal insulation system installed then this must be “unventilated” to keep this air warm and still. Failure to achieve this reduces the effectiveness of this air gap which is used to enhance U Value calculated values on the wall.
Failure to adequately deal with cold bridging at critical junction will increase the heat loss at this junction after the insulation has been installed which can lead to mould growth in these areas. A recent report published by the BRE states that heat loss at uninsulated junctions can be as high as 50% in certain cases.
At Enviroform Solutions we have addressed all of the above critical factors in the design of MagnaLine Slim complete with Magnablok to create a robust thermal laminate system.
“Off the shelf thermal laminates” will not achieve all of the above criteria due to their poor design and installation methods. The widespread use of these cost effective laminates?, coupled with the sectors lack of understanding of the effect, of not dealing with Cold Bridging contributes a large part of the “Performance Gap”.
STANDARD THERMAL LAMINATES EITHER FIXED ONTO BATTENS OR BY A “DOT & DAB” METHOD DO NOT FULFIL THE REQUIRED CRITERIA