Terrace size and price: how 20 m² compares with 40 m²

What changes when the area doubles, and what does not

Material quantity scales almost exactly with area: decking boards, joists, screws and stain all roughly double from 20 m² to 40 m². If a 20 m² deck uses about 22 m² of decking boards allowing for waste, a 40 m² deck will need close to 44 m².

Labour does not double in the same way. Setting out the frame, levelling the ground, and getting tools and materials on site takes a similar amount of time whether the deck is 20 m² or 40 m². That fixed portion of the job gets spread over more area on a larger terrace, which is why the price per square metre tends to fall as size increases.

Access and site conditions matter more than the size difference itself. A 20 m² terrace on a steep, narrow Nõmme plot with no vehicle access can cost more per square metre than a straightforward 40 m² deck on flat ground behind a new-build in Harju county.

Labour days: where the difference between 20 m² and 40 m² comes from

A straightforward 20 m² timber deck on an existing flat base, built by two people, typically takes one to two working days: setting the frame, laying boards, and finishing edges. A 40 m² deck of the same type usually takes three to four days, not double, because the setting-out and tool setup do not repeat.

Where the days really add up is joists and support posts, since both scale with area and take real time to level and fix. A 40 m² frame has roughly twice the joist runs and twice the posts of a 20 m² one, and each one needs to be checked for level before boards go down.

At our hourly rate from 39 €/h, a two-day job for one person and a four-day job scale in a way you can estimate directly: roughly double the hours, but with the call-out and setup counted once. For anything beyond a small repair or extension, we usually give a fixed quote rather than billing purely by the hour, since it is easier for you to budget against.

Foundation and base: this is where size genuinely drives the price

If the terrace needs new ground screws or concrete point footings rather than resting on an existing slab, foundation work is the part that scales hardest with area. A 20 m² deck at typical post spacing needs around 9 to 12 support points; a 40 m² deck needs close to double that, and each point means digging or screwing, checking level, and letting concrete cure if that is the method used.

Ground condition changes this further. Clay or waterlogged soil, common on many Harju county plots, needs deeper footings or ground screws rather than simple concrete blocks, and that cost applies per point, so it multiplies with the number of support posts a larger deck needs.

This is the section of a quote where a 40 m² terrace can end up costing more than twice a 20 m² one, even though the decking above it scales evenly. If your existing base or old foundation is reusable, ask specifically whether it can carry the new structure before assuming you need to start from scratch.

How material choice interacts with size to change the total

On a small terrace, the difference between pine decking and thermally treated ash or composite boards is a modest sum in absolute terms, even though the price per square metre gap is large. On 40 m², that same per-square-metre gap is doubled in real money, so material choice matters more as the project grows.

Composite decking costs more per square metre than timber but needs less maintenance over the years, and on a large terrace that upfront difference can be substantial, often several hundred euros between a timber and a composite version of the same 40 m² deck. On 20 m², the same choice is a smaller absolute gap and easier to justify either way.

Substructure timber is a good place to save on a bigger deck without affecting what you see or walk on, since pressure-treated pine joists perform the same job as more expensive species and the saving scales with the number of joists used.

What is usually included in a quote, and what is extra

A fixed quote for decking and terraces, from 90 € per job, normally covers setting out, building the frame and foundation points, laying and fixing the decking boards, and a basic edge finish. It does not usually include removing an old structure, since that is priced separately once we see what is there.

Staining or oiling the finished deck, balustrades, steps, and built-in seating are commonly quoted as additions rather than included by default, because not every terrace needs them and their cost depends heavily on the design chosen.

If materials are bought by us rather than by you, a 10 % handling fee applies on top of the material cost, which is worth weighing against the convenience, particularly on a larger order where the fee is a bigger absolute number.

• Included as standard: setting out, frame, foundation points, decking boards, basic edge finish
• Usually priced separately: removal of an old deck or base
• Usually priced separately: staining, oiling, balustrades, steps, built-in seating
• Materials: bought by you, or by us with a 10 % handling fee added
• Call-out fee of 25 € within Tallinn, deducted from the bill if the work goes ahead

How to work out the rough size of your own project

Start by measuring your planned terrace in square metres and multiply by roughly 1.1 to allow for board waste and cutting — that gives you the decking quantity to price against a per-square-metre material cost, whether timber or composite.

For support points, count roughly one post per 1.5 to 2 m² depending on joist spacing, then check whether your ground needs screws or concrete footings, since that decision affects each point's cost and therefore scales with your total count.

For labour, assume a fixed one to one-and-a-half days for setup and setout regardless of size, then add roughly one day per 15 to 20 m² of straightforward decking on a prepared base. That gives a working estimate you can compare against a quote, though uneven ground, existing structures, or an apartment association's approval process can all shift the real figure.

If your building has communal outdoor space managed by a korteriühistu, or the terrace touches a shared building's exterior, it is worth checking with the association before assuming the work can go ahead as planned. For ongoing upkeep once the deck is built, office and building maintenance from 49 €/h covers recurring jobs like re-oiling or seasonal checks.