Balcony or rooftop terrace in a flat: what's actually possible

What's the difference between a balcony and a rooftop terrace

A balcony is part of your flat, even if technically it belongs to the building's common structure in some associations. You can usually decide what goes on the floor of it without asking anyone, as long as you're not drilling into the structure or changing the facade side that faces the street.

A rooftop terrace sits on a shared roof, which is common property. It doesn't matter if your flat is the top floor and you're the only one who ever goes up there — the roof structure, waterproofing, and access belong to the building, and any change to it is a decision for the housing association, not for one owner.

This distinction decides almost everything else: what you can do without permission, what needs a vote, and what could put your waterproofing guarantee or the roof's own guarantee at risk.

What flooring actually suits a balcony floor

Interlocking WPC (wood-plastic composite) decking tiles are the most common choice for balconies, because they sit loose on top of the existing surface, need no fixing, and can be lifted again if you move out or the balcony needs repair. They come in roughly 30 by 30 cm squares that click together over a plastic grid base.

Real timber decking boards look better to some people but need a proper batten frame underneath, which adds height, weight, and a step up at the door. On a balcony with limited headroom or a low door threshold, that's often the detail that rules timber out.

Composite tiles cope with rain and freeze-thaw cycles better than most timber, and they don't need annual oiling. If you want the look of wood with less upkeep, that's usually the reasoning behind choosing composite over solid timber on a balcony specifically.

• Interlocking WPC tiles: no fixing, easy to lift, low maintenance
• Solid timber decking: needs a batten frame, raises floor height, needs periodic oiling
• Rubber or foam tiles: cheapest, softest underfoot, shortest lifespan outdoors
• Artificial turf tiles: common on Soviet-era panel block balconies, but hold moisture underneath if drainage is poor

Load and moisture: what actually matters, not what sounds impressive

Balcony load limits are set by the building's structural design, and panel-block balconies from the Soviet era were not built with a heavy deck, planters, and furniture in mind. A few square metres of light composite tiles and a couple of chairs is normally fine; a full soil bed for planting rarely is. If in doubt, ask your housing association whether the original load rating is documented anywhere.

The detail that causes more real damage than weight is drainage. Balconies are built with a slight fall towards a drain or the open edge, and covering that fall with a flat deck can trap water against the balcony slab, which is exactly what causes concrete spalling and rust staining on the floor below over a few winters.

Interlocking tiles with an open grid base let water run through to the original surface and drain as designed. Solid boards laid tight to the floor, or turf tiles left down over a wet autumn, are the ones that cause problems, because they hold moisture against the slab instead of letting it pass through.

A rooftop terrace is the housing association's decision, not one owner's

If you're picturing a shared roof terrace, the waterproofing membrane underneath is the single most important thing on the building, because a leak there runs down through every flat below. No responsible association lets one owner add decking, planters, or a pergola on top of it without checking what's underneath first.

In practice this means the request goes to a general meeting or the board: what's proposed, who pays, who's liable if the membrane is damaged during installation, and who maintains it afterwards. Associations that do agree to it usually want a fixed budget and a single contractor doing the whole job, rather than several owners each laying their own patch.

This is also where a decking and terraces job priced from 90 € as a fixed quote suits a shared project better than hourly work — the association gets one number to approve, and one invoice, rather than negotiating rates with several different people.

What you can do yourself and when to call someone in

Laying interlocking composite tiles on an existing balcony floor is genuinely a job most people can do themselves in an afternoon: sweep the surface, check the fall towards the drain isn't blocked, and click the tiles together starting from one corner. No tools beyond a saw for the edge pieces are usually needed.

Where it stops being a weekend job is anything that touches the balcony's drainage outlet, its edge fixings, or the building's facade — glazing brackets, railings, or anything drilled into the slab. Those affect the building's structure and its waterproofing, and are worth getting looked at properly rather than guessed at.

For a rooftop terrace specifically, once the association has agreed to go ahead, the actual build is a fixed-quote decking job from 90 €, based on photos or a site visit. Ongoing upkeep of shared roof access, drains, and gutters around the terrace fits naturally under building maintenance from 49 € an hour, arranged directly with the association rather than an individual owner.