I'm planning on replacing the old handrail on our garden steps, but figured it would be sensible to sort out the render on the stair wall first as there were quite a few cracks, loose render (where its blown) and weeds coming through.
All loose render has now been removed and brushed down with wire brush, but this has left quite a deep recess to build up (over 2" in some places) and the exposed concrete has a jagged, almost honeycomb structure to it - see imgur link for pictures.
Assume first step is to apply SBR to increase adhesion/reduce moisture suction, but I'd really appreciate some advice on the best building aggregate to use (would prefer a premix given my lack of experience if possible, but appreciate this often isn't the best solution). I bought some Bostik Cementone Render Repair, but this can only be used up to 15mm depth and so imagine it would only be suitable for the penultimate scratch coat and the final finish. Don't think it's the right choice the building up the wall depth. They do offer an epoxy deep fill mix but it's super expensive.
Any advice on the best way to fix up the steps and refinish them would be greatly appreciated as well.