Insulated render facade in Batumi: insulation and decorative render

Insulated render facade in Batumi: how it works

In Russian this facade is called "wet" because every layer goes on the wall as a mortar: adhesive, base coat, primer, decorative render. The insulation is glued to the wall and also fixed with dowels, glass fibre mesh is embedded in the base coat on top, and only then comes the finish. The result is a thin, light and warm shell around the house with no metal and no air gap. An insulated render facade in Batumi is cheaper than a ventilated one and works well if all layers belong to one system and the junctions are done with care.

How it behaves by the sea compared with a ventilated facade is covered in our comparison of ventilated and insulated render facades. Here we explain how it is built.

Layers in order

• wall preparation: cleaning, repairing chips, primer, flatness check;
• a starter track with a drip edge, from which the first row of insulation begins;
• adhesive around the board edge and in dabs in the centre, boards in a staggered bond;
• dowels after the adhesive has set, to a pattern for corners and the middle of the wall;
• a reinforced base coat with overlapping glass fibre mesh;
• primer and decorative render, then facade paint.

All materials come from one system by one manufacturer. An adhesive of one brand and mesh of another may not suit each other, and then nobody will give a warranty on the facade.

Mineral wool or expanded polystyrene

Mineral wool does not burn and lets vapour through, so it is our choice for aerated concrete and porous blocks. Expanded polystyrene is cheaper and easier to work, but vapour hardly passes through it, and on aerated concrete the moisture stays in the wall. We use it on concrete and solid brick, and above windows of multi-storey buildings in such a facade we fit mineral wool strips as fire breaks. How to choose the insulation thickness and material is explained on the facade insulation page.

Window corners and joints

An insulated render facade cracks in predictable places: diagonally from the corners of windows and doors, at joints between concrete columns, slabs and masonry, and at the corners of the house. So at every corner of an opening we bed diagonal mesh strips before the main mesh, fit corner beads with mesh on the corners of the house, and profiles with a drip edge on the reveals. At joints between different wall materials the mesh runs well past the joint on both sides. Insulation boards are cut so that their joints do not line up with the corner of an opening.

Finish coat and colour

For a house by the sea we choose silicone or mineral decorative render: silicone hardly absorbs water yet lets vapour out of the wall. We advise against dark colours on the south and west walls of an insulated render facade: a thin coat of render over insulation heats up more than over masonry, and temperature swings cause cracks. If you want a dark accent, we do it on a small area or in another material. For smooth surfaces without insulation there is a separate technology, see the rendered facade page.

Weather and timing

Each layer of an insulated render facade must dry before the next one, and rain washes fresh mortar away. In Batumi we work on these facades only in dry weeks, cover the scaffolding with netting against sun and wind, and if a downpour threatens we cover the fresh coat with sheeting. In hot weather we work mornings and evenings: on a scorching wall render sets in patches. In summer this facade noticeably reduces wall heating, and for houses where every saving counts see the energy-efficient houses page.

How much an insulated render facade costs

A turnkey insulated render facade with materials costs from 205 ₾ per m²: insulation, adhesive, dowels, reinforcement, primer, decorative render and paint. Labour for insulation with reinforcement, using the client's materials, from 69 ₾ per m². Insulation with 100 mm mineral wool and reinforcement but no decorative coat from 145 ₾ per m², with expanded polystyrene from 115 ₾. Reveals and sills from 54 ₾ per linear metre, stone or clinker plinth cladding from 300 ₾ per m², scaffolding from 18 ₾ per m² of facade. The final cost is set after measuring the facade and agreeing the estimate.