EWI is used for improving the thermal resistance value of existing external walls to enhance their thermal insulation.
EWI is the preferred method for insulating a property with a solid wall, repairing non-traditional housing, or improving a building that has severe heating issues. It should not be applied to walls with rising damp.
An EWI system is an insulation layer attached to the wall. Then it is covered with a protective and ornamental render, brick effect, or claddingfinish.
An insulation layer can be made of expanded polystyrene or phenolic foam, polyurethane foam boards, or mineral wool batts. A render finish is an overcoat of primer, a cement-based mineral or synthetic base coat with mesh reinforced and then coated with a render finish. After the primer is applied, a top coat render can be applied. This will give you a smooth, textured or painted finish. Dry cladding is made up of timber boards and aluminium panel; brick effect finishes are brick slips, stone tiles, or clay tiles.
EWI offers many benefits: improved protection of external walls from rain penetration to the interior, reduced heat loss and lower heating/energy costs, reduced CO2 emissions, lower heating/energy bill, reduced draughts through windows and around walls, better sound resistance, and a more attractive appearance (i.e. greater ‘kerb appeal’).
Warm walls can reduce the chance of condensation on interior wall surfaces, and they help with damp problems.
EWI will alter the appearance of a property’s exterior. Before any work is undertaken, you will need to obtain planning permission. EWI must be installed according to the national Building Regulations. EWI may be restricted in its location or height due to the reaction to fire. This is largely determined largely by the materials chosen for use.
Before any property can be installed, it must be surveyed by PD Rendering. An incorrect treatment could cause long-term damage to the building fabric. An expert must perform a condensation risk analysis if it is necessary. Vapour barriers must be placed between the insulation and the wall to prevent condensation from occurring.
The wall type determines which EWI will be used for the specific project. For example, solid stones walls can be breathable which allows moisture to penetrate and evaporate a little. A breathable MW insulation combined with a non-acrylic external render, or another finish, will ensure that the wall is able to breathe.
Walls made of brick may be impermeable and resistant to moisture penetration. For such walls, rigid foam insulation is ideal.
For room space ventilation, window trickle vents or extract fans must be installed in high-humidity areas.
High standards of installation are required for property fabric-related work. Poor detailing e.g. Poor detailing, e.g.