Balconies, Verandas and Falls

On a balcony or veranda the floor has two jobs. It has to be pleasant and safe to walk on, and it has to send rainwater away from the house. When the second job isn't done properly, the problem usually shows first on the ceiling of the floor below or at the balcony door sill.

Falls

A balcony floor should slopeFalls (drainage slope)The gentle slope built into flat roofs, balconies and bathroom floors so water runs to the drain or gutter instead of pooling. gently towards the drainFloor drainThe outlet in a floor where water drains away on roofs, balconies and in bathrooms, with a grate on top and usually a trap below. or the gutterGutter and downpipeThe channel and pipe that collect rainwater from a roof and carry it down to the ground or the drains., and always away from the door. The slope doesn't come from the tiles but from the layer under them, usually screedScreedA layer of sand-and-cement mix or lightweight concrete poured over the slab to create falls and a solid surface for the next material. or cement mortar, laid when the floor is built.

That's why, when water pools or runs towards the door, a new coating on top doesn't fix it on its own: it follows the same surface. Small hollows can be filled locally before the new layer goes on. But if the whole floor leans the wrong way, the slope only changes if the layer underneath is redone.

Signs that the falls aren't working: water left standing after rain, dark or green marks in the corners, dirt that always collects in the same spot, and damp at the door sill.

The tiles

On balconies the groutGrout jointThe gap between tiles, slabs or stones, and the material that fills it. Grouting means filling these joints, which locks the surface together and keeps out water and dirt. darkens and opens up, and some tiles come away from their base. A simple test is to tap them lightly with the handle of a screwdriver: the ones that sound hollowHollow (debonded) tilesTiles or slabs that have come away from their base. They sound hollow when tapped lightly, and often rock or crack. have usually come loose. Depending on what turns up, there are three main routes:

• A few damaged tiles or joints. Only the tiles that have come loose or crackedCrackA split or gap in render, concrete, a wall, a coating or wood. Fine cracks are usually only on the surface; ones that grow, keep reopening or run diagonally need attention. are replaced, and the joints are renewed. The hard part is finding matching tiles.
• Sound tiles, but water getting through. If the tiles are firmly stuck, a waterproof coatingElastomeric waterproof coatingA thick, rubbery waterproof paint for flat roofs, parapets and roofs. It stretches without cracking as the building expands and bridges hairline cracks. can go over them without breaking anything. That is waterproofingWaterproofingThe work and materials that stop water getting through on flat roofs, balconies, bathrooms, basements, planters and tanks. work, and it changes how the floor looks.
• Many broken or hollow tiles, or wrong falls. Then the floor usually has to be stripped, given new falls and waterproofing underneath, and laid again from scratch.

On one terraceFlat roof (roof terrace)The flat concrete roof on top of a building. It is the most common kind of roof in Greece and the part that takes the most sun and rain. the irregular marble slabs had cracked and come loose. They all came up to show what was underneath: a joint with rottedWood rotDecay of wood caused by fungi when it stays damp for a long time. Rotten wood goes soft, gives when pressed or crumbles, and can't be saved with paint. wood inside it and a crack running along the floor, the kind of spots where water finds its way in. Once these were cleaned out and sealed, the terrace got a new, continuous grey layer, with no broken pieces and no open joints.

If new tiles are laid

• They need to be tiles for outdoor use, which stand up to the cold and don't get slippery when wet, in other words slip-resistantSlip-resistant surfaceA floor, tile or paint with a textured finish that doesn't get slippery easily when wet. It's needed on balconies, courtyards, steps and around showers. tiles.
• The tile adhesiveTile adhesiveA ready-mixed cement-based mortar, sold as a powder and mixed with water, used to stick tiles to walls and floors. It is spread with a notched trowel. and the grout need to be suitable for outdoor use.
• The waterproofing goes down before the tiles and runs a little way up the wall, because the corner between floor and wall opens up easily.
• The drain and the door sill need particular care: water should end up in the drain, not at the door.

What to ask

• Which way will the water run, and how will the slope be checked before the tiles go down?
• Will there be waterproofing under the new floor?
• What will be done at the corner with the wall and at the door sill?
• Where will the rubbleDebris (rubble)The waste that comes out of demolition and building work: broken tiles, render, bricks and concrete. It is collected in bags and has to be disposed of legally. from stripping the floor go?

Every balcony is different, and the right fix depends on what is under the tiles. That's why the first conversation always happens on site, with the floor in front of you.