Managing critical points

Key aspects of external wall insulation: definition and essential accessories

Where a façade really comes into its own

The critical points of an external wall insulation system are the areas where the insulation is interrupted, changes direction or is subjected to a load: the base of the façade, corners, window reveals and lintels, parapets and shutter hinges. These are also the areas where most problems arise: cracks, water ingress and thermal bridges. Installation begins at the bottom of the façade with the aluminium starter rail. This ensures the first row of insulation is level, protects the bottom edge from impact and channels away rainwater. Its width is chosen according to the thickness of the insulation: 143 mm for a 140 mm panel, for example. It is fixed every 30 to 50 cm, joined using connectors and cut at a 45° angle at the corners. At the top of the wall, the coping rail provides a neat finish to the system. On vertical edges and around openings, the PVC corner bead with fibreglass mesh is embedded in the base coat. It reinforces the corner, resists the alkalis in the render and prevents cracks. Above windows, the drip profile stops water running down so that it does not flow towards the window frames. Finally, the corners of openings are reinforced with a diagonal mesh laid before the general reinforcement.

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Fitting shutters and load-bearing elements to external insulation

Well-maintained shutters, with no thermal bridges

A shutter hinge cannot be fixed directly into insulation. It requires a rigid support, integrated into the external thermal insulation system (ETIS) before the render is applied, which bears the weight of the shutter without creating a thermal bridge. Several solutions are available from Centrale ITE:

The Blok shutter hinge is a block made of high-density polystyrene (200 kg/m³) which provides insulation whilst offering mechanical strength. It is bonded and mechanically fixed using the fixings supplied. Once the façade has been rendered, the hinge is fitted simply by screwing it in (threaded hinge) or using chemical anchoring (non-threaded hinge), with drilling carried out using a template.
The ARKTIC external wall insulation hinge blocks measure 200 × 100 mm and are available in thicknesses of 120, 140, 160 and 180 mm, to be selected according to the thickness of the insulation.
The ISO hinge bodies (Ø 25 or 30 mm, span up to 160 mm) and shutter offset brackets shift the pivot point outwards, across the full thickness of the cladding.

For joints around joinery and penetrations, PU foam and MS adhesive complete the range. On certain buildings insulated with EPS, fire regulations also require rock wool fire barriers (Euroclass A1). We can help you check whether your project is affected.

How to choose your external insulation?

Steps involved in an EWI installation

Which fixing for which substrate?

Key aspects of external wall insulation: definition and essential accessories

Good habits to adopt before getting down to the nitty-gritty

Choose a rail that is slightly wider than the thickness of your insulation: 123 mm for 120 mm, 143 mm for 140 mm, 163 mm for 160 mm. The panel should fit snugly with no gap. Fix the rail every 30 to 50 cm and join each 2.5 m section to the next using a connector.

Yes. The PVC angle bead with fibreglass mesh reinforces every protruding corner of the façade and openings. It is embedded in the still-wet base coat, protects the edge from impact, prevents cracks and gives the finishing render a straight, clean line.

A rigid support must be incorporated into the insulation before the render is applied: either a high-density EPS shutter hinge block or a hinge shim of the same thickness as the insulation. Once the façade has been rendered, the hinge is screwed or chemically anchored into it, without creating a thermal bridge and without compressing the insulation.