Render Systems Installation

External render for Manx weather — and the right system for the wall you have.

Rendering on an Island

Nearly half our work is external, and the conditions here are the reason the specification matters more than it would elsewhere. Wind-driven rain, salt on any elevation within sight of the sea, and a great many solid-walled properties that were never built to be sealed.

Breathability is not a preference

An older solid wall has to let moisture out through its face. Put a film-forming coating on it and the water has nowhere to go: it sits in the wall until it pushes the coating off, taking the surface with it. We are called to undo that more often than anything else. Where a building is old, the system has to be breathable — lime, mineral, or cork.

Over what is already there

The assumption is usually that old dash or failed render has to come off first. Often it does not. Spray cork is super-adhesive and takes to dash; thin coat systems go over sound render. That is faster, cheaper and far less disruptive than hacking a house back to brick — but it only works where what is underneath is sound, which is the first thing we check.

Insulation

Over a third of the heat lost from a property goes through the walls. Where there is something to insulate into, external wall insulation with a render over it is the thorough answer. Where there is not — a solid wall, or a building that cannot be altered outside — sprayed cork works from the inside at about 8mm.

Systems we install

Spray cork

Insulating, breathable, algae and salt resistant, and it goes over existing pebbledash.

Lime and mineral

The breathable route for older and registered buildings.

Light weight thin coat

Mesh-reinforced, flexible, applied over an existing wall.

Monocouche and through-colour

The colour runs through the render.

Insulated render (EWI)

Insulation fixed to the wall, then a light weight render over it.

Cement render and pebbledash

Where matching what is there matters.

Our Process

1. Assess the wall

What the wall is built of decides everything. A solid stone wall has to breathe; a modern cavity wall does not care. Getting this wrong is what causes most of the render failures we are called out to.

2. Specify the system

Cork, lime, thin coat, monocouche or traditional — chosen on the building rather than on preference, and then the colour and texture chosen on top of that.

3. Prepare and repair

Blown render cut out, pointing repaired, algae killed off, salt washed down on a coastal wall. Nothing goes over a surface that is not sound.

4. Base coat and mesh

Most modern systems are a base coat with an alkali-resistant fibre mesh bedded into it. The mesh is what lets the wall move without the render cracking.

5. Top coat

Through-coloured silicone, mineral or cork, in the texture chosen. On a through-coloured system the colour goes all the way in, so a chip does not show as a scar.