EWI Application Information
External Wall Insulation
External Wall Insulation (EWI) or Solid Wall Insulation is a type of insulation wrapped around the exterior of your house and completed with a wide range of finishes. EWI is the perfect solution not only for houses that were built before 1920 but for builds with cavity wall insulation issues. EWI has many benefits over other insulation's.
- increased savings on energy bills
- revitalise's the appearance of your home
- improves weatherproofing
- reduces noise penetrating through
- usually applied without disruption to the household
- does not reduce the internal floor space of your home
- Protects the existing brickwork
- Can help prevent damp issues
There are a many companies who have developed EWI systems for the protection of your home. At Amaroc we are working with some of the best systems available on the market. As stockists for JUB and KRend systems we can offer a wide range of top coat colour finishes at next day delivery.
System Components & Application
* Please see below the step by step application of a typical external wall system
Base Tracks - AKA Base Profiles or Starter Tracks - Base Tracks are aluminium moulded profiles that are mechanically fixed to the substrate. The tracks are used to perform a starting point just above damp proof cause to hold the EPS boards and fix drip beads to ensure water flows away in the correct manner. The track should be of similar width to that of the EPS board and fixed with suitable fixings to the substrate.
The type of fixing used to secure the base track differs depending on the substrate usually at 300 mm maximum centres. Connectors are used to attach lengths together. For uneven substrates use spacers to bridge the gaps to provide a solid fixing. Beads and expansion joints are incorporated as specified. For solid walls use a hammer screw fixing, usually 6 x 35mm is sufficient.
For ply wood use a stainless steal fixing
Adhesive Mortar - The KRend and JUB range of adhesive mortars provides the perfect base for fixing all types of external insulation boards. Please refer to the systems technical guide or BBA certification around whether you are required to use adhesive mortar as well as mechanically fix.
KRend Base Coats
Jub Base Coats
Typically adhesive should be mixed in a suitable container using water and a high power drill and mixer spiral to create a paste-like mortar whilst ensuring there are no clots in the mixed material. The insulation boards are positioned on the starter track and initially bonded to the wall by applying the specified adhesive to the boards using the ribbon and dab method. A circumferential ribbon of adhesive, at least 3 cm wide, is applied to the insulation boards. Six to eight evenly distributed patches of adhesive, 8 cm to 12 cm in diameter, are then applied to the boards so that an adhesive surface of at least 40% is achieved.
Alternatively, for even and smooth substrates, the whole panel can be coated with adhesive using a notched trowel to produce a coat 2 mm to 5 mm in thickness. The insulation panel should be immediately placed on the substrate and pressed into place.
EPS - Our range of Expanded Polystyrene (EPS) insulation boards are available in a range of thickness providing excellent insulation.
The boards are always laid in brick bond fashion. See Figure 1 below. Care is taken to ensure that the boards are fitted tight to each other. The boards are interlocked on the external corners. Gaps are filled with expanding PUR foam.
The first run of insulation boards is positioned on the base profile.
The fixings are installed by drilling through the insulation and into the substrate. Care is taken to ensure that the depth of embedment of the fixing into the substrate is as specified. Allowance is made where either existing render is on the wall or dubbing out render has been used to align the boards as the effective embedment will be reduced. The fixings are either hammered or screwed in depending on the type specified.
Fixing Anchors - Insulation Boards are secured using fixing anchors which are available in Plastic or Plastic / Metal. There are a wide variety of ways to fix the EPS boards to the substrate, these are usually demonstration on the BBA Certifications of the system you are using.
At Amaroc we offer a range of fixings to cater for the system you are using and the substrate being fixed to.
Holes are drilled into the substrate through the insulation, and the fixings are installed, fixed tightly to the insulation board using the dedicated driving system to ensure there is no risk of pull off. Care must be taken to ensure that the fixings are not overdriven.
Fixing patterns will vary according to the system you are using so always refer to the technical specification or BBA certification. Below are a few examples you might typically find
Check the certification first but as a general rule you would want to use 5 insulation anchors per board.
Thin Coat Render Beads
Drip Ledge Beads
Drip beads are attached to base tracks either with a self adhesive or clip fixing. They are used to create a small lip to ensure water flows away in the correct manner
Self Sealing and Clip On Drip Ledge Beads
Corner Mesh Beads
Apply meshed corner beads on all corners to provide reinforcement to the system. Use the system base coat to adhere the beads to the EPS. Amaroc supply two types of corner mesh beads. The 6mm nosed bead gives you advantage point to render up to providing a perfect finish to the corner.
Self Sealing Window Beads
Our range of self sealing window beads provide the perfect finish around the window frames. The self sealing strip is attached to the window frame providing a water tight seal that will mean you no longer have to use silicone to seal the system. The 6mm nose gives you a perfect point to render up to and with an additional snap off strip to attach window protection film to these are essential to you installation. They are either used with or without mesh
Reinforcing Mesh - Reinforcing mesh is essential in all EWI Systems to reinforce the render, especially so around openings or areas of weakness, and to cover and help prevent cracking.
There are many cheap meshes on the market so make sure the mesh you are purchasing holds either the European Standard ETAG or BBA Certification. Our range of meshes are certified to European industry standards
The fibreglass mesh should be embedded into the first applied keyed base coat usually around 3mm thick. The sheets of mesh should be lapped by a minimum of 100 mm. Diagonal patches of mesh approximately 300 mm by 200 mm should also be installed at the corners of window/door openings. The second 3 mm thick coat of basecoat should be applied to give a total render thickness of 6 mm. The surface of the basecoat should be sponged, to provide a smooth surface for top coat finish.
A range of primers improve adhesion of renders to very smooth surfaces. The primer is applied to the basecoat in accordance with the Certificate holder’s instructions and allowed to dry for approximately 24 hours prior to the application of the finishing coat. Amaroc stock both KRend Primer and Jub Primers.
Apply using a brush or a roller
A range of decorative renders to give an aesthetic look to the surface, and additional protection against the weather effects
Ensure the top coat is thoroughly mixed prior to application. Apply with trowel and hawk to a thickness in relation to the size of the grain within the top coat. Using a plastic trowel float up for finished look.
Please refer to the product technical guide prior to using.
Top Coats and Primers come in a range of colours. Please click on the link below to view the range of colours KRend & Jub manufacture
Below are some standard colours. We can tint the full range of NCS and RAL colours on site for next day delivery. Call on 01793 496277 to discuss option