by What are External Wall Insulation Boards?
External wall insulation boards, commonly known as EWI boards, are rigid insulation panels that are externally fixed to existing walls of homes or buildings for improved thermal insulation and aesthetics. EWI boards provide an affordable and effective solution to insulate solid brick or block built walls from outside without compromising the internal floor space.
Types of External Wall Insulation Boards
There are various types of EWI boards made from different materials suitable for different project requirements:
Mineral Wool Boards
Mineral wool insulation boards are one of the most widely used types of EWI boards. Made from stone wool or slag wool, mineral wool boards are durable, fire resistant and breathable. They provide an insulation value of around 1-2m2K/W.
Expanded Polystyrene (EPS) Boards
EPS insulation boards have high insulation properties and are lightweight to handle and install. However, they are not suitable in areas with high moisture as they can absorb water. EPS boards have an insulation value ranging from 3.5-5m2K/W.
Extruded Polystyrene (XPS) Boards
XPS boards offer high insulation and are resistant to moisture. They have insulation values between 3.5-5m2K/W but have a higher price than EPS boards. XPS boards are a preferred choice for projects in damp areas.
Wood Fibre or Fibre Cement Boards
Wood fibre and fibre cement boards provide an aesthetically pleasing finish to walls while offering suitable insulation worth 1-2m2K/W. However, they require protective render coats for durability.
Benefits of Using External Wall Insulation Boards
Instaling External Wall Insulation Board allows homeowners to considerably improve the insulation of existing solid walls without major construction work. Some key benefits include:
– Thermal efficiency: EWI boards significantly reduce heat loss through walls by providing a thermal envelope. This decreases energy costs for heating.
– Soundproofing:The additional layer creates a sound barrier that minimizes noise penetration from outside.
– Moisture resistance: EWI boards protect walls from external moisture, dampness and mould growth behind the cladding.
– Fire safety: Non-combustible mineral/stone wool boards offer fire resistance and safety.
– Modernization: EWI visually upgrades plain brick/block walls and adds aesthetic appeal.
– Internal space gain: Unlike cavity wall insulation, EWI doesn’t reduce the internal floor area.
Application and Installation of External Wall Insulation
For successful application of EWI boards, the wall surface must be prepared properly before fixing insulation panels. The steps involved are:
– Wall repairs if required, filling cracks or holes.
– Applying suitable primers and adhesion promoters on surfaces to be bonded with insulation boards.
– Mechanically fixing insulation boards to walls using approved fixings at specified intervals.
– Sealing board joints, edges and penetrations properly with joint sealant tapes.
– Applying reinforcement mesh tapes at board joints for impact resistance.
– Finishing layers – Base coat, reinforcing coat and finished decorative top coats of render, cladding or tiles.
Benefits Far Outweigh the Upfront Costs
While the initial capital cost of EWI installation is higher than traditional internal wall insulation, the life cycle cost savings through energy efficiency and maintenance outweigh the higher upfront cost. EWI delivers maximum return on investment through long term heating cost reductions and protection of the building fabric. With proper specification and installation, EWI significantly extends the lifespan of existing homes and buildings.
The external application of insulation boards provides an innovative solution to maximize thermal performance of buildings in a sustainable manner. By increasing energy savings every year, EWI technology proves to be a smart investment for homeowners looking to futureproof their properties with enhanced insulation. With a variety of board types available, EWI continues to be the preferred choice for retrofitting solid wall constructions.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
