Aerated concrete vs brick for a house by the sea in Batumi

In countries with cold winters, the aerated concrete vs brick choice comes down to frost and wall thickness. In Batumi, frost resistance hardly matters: even in January the average overnight low stays above freezing. What decides it here is water, the weight of the wall in an earthquake and how the wall performs in a house where guests stay.

Water and the facade: the main difference by the sea

Aerated concrete soaks up water through its pores and gives it back slowly. A wet wall loses more heat, and under dense paint or cement render the moisture gets trapped, so by winter mould can appear on window reveals and in corners. By the sea an aerated concrete wall always needs a facade.

Two solutions work: a ventilated facade with an air gap, or a render system made for aerated concrete in which every layer lets vapour through. All the layers have to come from the same system. Otherwise, somewhere on its way out, the vapour meets a dense layer it cannot pass.

Fired clay handles water differently. Brick gets wet too, but it dries quickly and keeps its strength, and facing brick needs no other finish. The weak point of a brick wall is the mortar: if the bricklayer uses too little of it in the vertical joints, wind-driven rain finds its way in.

Seismic load, weight and insulation

The seismic load on a frame grows with the mass it carries. Brick infill weighs noticeably more than aerated concrete, so the frame and foundations for brick walls are designed for a bigger load, and that shows in the estimate. Aerated concrete walls make the house lighter, and where the ground is weak or the plot slopes, that is a real saving.

But aerated concrete is a soft material. We put reinforcement into the courses under the windows and along the top of the wall and use precast or cast-in-place lintels over openings. The wall is fixed to the columns with flexible ties, as the structural design specifies. Brickwork is tied to the frame too, but the brick itself has more strength in reserve.

On insulation it is the other way round. In summer an air-conditioned house takes in heat through its walls, just as it loses heat through them in winter. Aerated concrete holds the indoor temperature better than brick of the same thickness. A brick wall needs insulation to do the same, and that insulation has to be protected from water too.

Aerated concrete vs brick in a house you rent out

Between the rooms of a guest house you hear less through a brick wall, because mass is what stops sound, and aerated concrete has little of it. If you still want aerated concrete partitions, we make them thicker or line one side with plasterboard on a separate frame, with mineral wool behind it.

The second everyday difference is fixings. On aerated concrete walls, the outdoor unit of the air conditioner, the water heater, a TV on a wall bracket and kitchen cabinets hang on special anchors for this kind of block. An ordinary wall plug comes loose over time. It is better to mark where heavy items will go before the walls go up and build fixing points into the wall there. Brick has fewer of these problems, as long as you don't drill into the voids of a hollow brick.

Build time and the rainy season

Aerated concrete goes up fast. The blocks are large and even, and they are laid with thin glued joints. Brick is slower and needs an experienced bricklayer, especially facing brick. In Batumi, autumn and early winter are the wettest part of the year, so it makes sense to have the walls under a roof before September.

This is where aerated concrete has a downside. Blockwork that has stood through a rainy season without a facade takes months to dry out, and you cannot render it until it does. That is why we don't leave an aerated concrete shell open over the winter. If we cannot finish the facade in time, we cover the tops of the walls and the openings until spring.

Repairs and checking by photo

Aerated concrete is easier to repair. Cutting a channel for a cable is quick, and chips are patched with repair mortar. Brick gets damaged less often, but any alteration to a brick wall is noisy and dusty, and guests in the house will notice.

If you follow the build through our reports, ask to see the work that render and plaster will later cover: the damp-proof course under the first row of blocks, the reinforcement in the block courses and the lintels over the windows. If the aerated concrete is clad in brick, add the ties between brick and block and the vents at the bottom of the air gap to the list. All of this goes into the photo report before it is covered, and later into the handover file.