How to apply render over existing render

Common issues and queries you can face

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Render coats are applied in successive layers

Render coats are applied in successive layers in decreasing thicknesses and strengths.

Topcoats, therefore, may be relatively weak. It is difficult to assess the strength of existing materials and their bond strength to previous layers.

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Stresses from additional materials

Additional materials put increasing stresses on the bond interfaces of existing materials.

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Dirty deposits

Dirty deposits accumulated over a period of time can form a weak intermediate layer that interferes with the development of the bond of newly applied render.

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Poor key

Renders need a combination of mechanical key and suction to bond to the wall. Existing render surfaces even though unpainted or coated are usually “palin face” and seldom have sufficient key to hold a new render.