Monarflex Moisture and vapour barriers

What is a vapour control layer and where is it installed?
A vapour control layer is a vapour tight membrane that is installed on the warm side (facing towards the liveable area) of a roof or on the inside of the exterior house wall. The function of a vapour control layer is to avoid moisture that builds up inside a house, tol find its way to the insulation material, which then will absorb the moisture making the insulation material lose its ability to insulate.

If a vapour control layer is installed in a wall, it must be a light construction, meaning that the inside wall of the house should be made from wood, gypsum or similar light weight building materials for walls.

Why use a vapour control layer?
Not many are aware of why the vapour control layer (VCL) is so essential. Consider what happens when warm and cold air meets and what will this mean for the building physics in winter and summer climate. When warm air meets a cold surface condensation occurs and water/moisture starts forming, this is what you normally see on a cold glass on a warm day. Then try to think of this in the context of a building.

The indoor air needs to absorb the moisture that builds up in a standard house with 2 adults and 2 children living under normal conditions. This can be as much as 10 litres of water per 24 hours. All this water vapour naturally needs to go somewhere and since it cannot all be ventilated out by opening a window (which is not something everybody does during winter time), a need for a VCL is obvious. Without the VCL the saturated vapour will migrate through the light construction wall and into the insulation material where water will form. A properly installed VCL will help to prevent this.

The following factors may lead to problems with moisture/vapour in a construction:

• Vapour from indoor climate
• Building moisture in construction materials
• Ground moisture

Product range
The Monarflex product portfolio for vapour control layers covers all the needs for different applications ranging from ordinary houses with regular levels of water vapour to swimming halls with extreme water vapour build up.

The vapour control layers from the Monarflex portfolio is one of the widest on the market as it covers all three categories for vapour loads:
• Low loads – Ordinary houses
• Medium loads – Ordinary houses and industrial buildings
• High loads – Industrial buildings and swimming-/sports halls

The products in the low load category are made from virgin polyethylene with or without a reinforcing grid, and with a total thickness of minimum 200 micron.

Products that are in the medium load category are made from polyethylene with a total thickness of minimum 250 micron and always reinforced to prevent tearing during the crucial installation.

Products in the high load category are all made polyethylene with a reinforcing grid of polyester and a pure sheet of metalized film to ensure that no vapour can penetrate the protective VCL

Monarflex current vapour control barrier portfolio comprise of:

Low water vapour load

•MONARFLEX® Tough Skin

•MONARFLEX ® Elephant Skin
• MONARFLEX® Netofol 200 VB

Medium water vapour load

• MONARFLEX® Monofilament 250
• MONARFOL® Super
• ICOPAL® MonarVap Reflex

High water vapour load

• MONARFLEX® Polykraft STD
• MONARFLEX® Polykraft RE
• MONARFLEX® Reflex V-TEK
• MONARFLEX® Reflex 275

Foundation – moisture membrane

• Icopal® DPC RG

•Monarflex Radon DPC 500

Choose the right product

When having to choose the right product for the job, it is very important to remember that the vapour control layer has the same function as a roof underlay, but is installed on the warm side of the insulation material for protecting it.

The following conditions most be evaluated before choosing the product:
• What kind of moisture load can be expected – high, medium or low
• Should the product be used in walls, roof or floor
    o Monarflex product used in walls:
        - All our VCL products
    o Monarflex products used in roofs
        - All our VCL products
    o Monarflex products used in floors
        - MONARFLEX® Elephant Skin
        - MONARFLEX® Monofilament 250
        - MONARFLEX® Reflex 275
    o Monarflex product used as foundation moisture barrier
        - Icopal® DPC RG & MONARFLEX® Radon DPC 500

• If the VCL is installed close to a heating source like a radiator the ageing properties of the membrane is crucial to consider as prolonged exposure to heat has a degrading effect.
All Monarflex membranes have excellent ageing properties.

Trend
In later years, incorporating reflective properties into the VCL has become a trend among manufacturers. The reason for having a reflective vapour control layers is to reduce the heat loss from the building during winter time thus reducing the need for indoor heating. Monarflex has of course followed this trend and as a result have products like MONARFLEX® Polykraft and ICOPAL® MonarVap Reflex in our VCL portfolio.
An important note to remember is that reflective membranes only reflect

Importance of application
In order to get the optimal protection out of a Monarflex VCL it is important to recognize the fact that the accessories, as well as the installation process, play an equally important role as the vapour control layer itself.
When combining the different Monarflex accessories with the Monarflex VCL you ensure that a TOTAL protection system is formed that will assist the vapour control layer in providing the best possible protection.