How to choose the right decking material and build a durable terrace

Terrace construction always starts with one of the most important decisions: which decking board to use. In Estonia’s climate a terrace must handle rain, snow, sun, temperature swings and moisture. If the material or structure is chosen incorrectly, a terrace can start warping, cracking or growing mould within just a few years.

The right decking material affects not only the look, but also lifespan, maintenance needs and how straight and stable the terrace remains over time. In this guide we compare common options — pressure-treated wood, larch, thermally modified wood (thermowood) and composite decking — and explain which solution fits different needs and budgets.

Why choosing the right material during planning matters

A terrace is not just a decorative feature — it must be strong, stable and long-lasting. Estonia has multiple freeze–thaw cycles each year, which makes materials expand and shrink. If you cut corners on material or installation, a terrace may sink, become wobbly, warp or collect water in the wrong places.

A good decking material is dimensionally stable, weather-resistant and matches how you use the space. For example, a shaded north-facing side needs a more resilient material, while on a sunny south-facing side natural larch can perform very well. A smart choice made early saves money, time and maintenance effort.

Decking material comparison: which board should you choose?

The table below helps you quickly compare maintenance, lifespan and price level. Actual durability always depends on installation quality and the substructure.

*Lifespan is approximate and depends on installation, substructure, ventilation, maintenance and site conditions (sun/shade, moisture, soil).

Materials in more detail

Pressure-treated decking – affordable and classic

Pressure-treated pine is one of the most common decking materials. It’s affordable and easy to install, but it needs regular maintenance. Without oiling, wood can dry out, crack and develop mould in damp areas. If you want an affordable terrace that is covered or easy to maintain, pressure-treated wood can be a sensible choice.

Larch – natural and durable

Larch is naturally more weather-resistant and doesn’t require chemical treatment. Over time it turns grey (a natural process), while strength remains. Larch is a good fit if you value a natural look and understand that the wood is denser and requires careful installation.

Thermally modified wood – stable, premium choice

Thermowood is heat-treated, making it more dimensionally stable and biologically durable. It’s ideal if you want a high-quality, aesthetic terrace that “moves” less than regular wood. The colour stays nicer if you use UV-protective oil, but you can also let it weather naturally.

Composite decking – low maintenance

Composite doesn’t need oiling or painting. It’s a great choice if you don’t want to do seasonal maintenance every spring. Composite is also slip-resistant and works well for families and high-traffic terraces. Keep in mind that darker composite can get warmer in direct sunlight.

Why a good board alone isn’t enough

Even the best decking material won’t perform well if the substructure is weak. The frame should be properly protected, correctly supported and designed to manage moisture. The geometry and ventilation determine whether the terrace stays straight after a few years or starts sinking and wobbling.

A professionally built terrace:

• doesn’t sink or wobble
• doesn’t collect water and dries faster
• has correct board spacing (expansion/shrinkage)
• uses suitable fasteners (stainless steel, hidden systems)

Fasteners and additional materials

Decking screws and stainless steel fasteners

For larch and thermowood it’s recommended to use stainless steel to avoid staining and corrosion. Standard wood screws or lightly galvanised screws can rust over time and damage both the boards and the overall appearance.

Hidden fastening / screwless installation

Hidden fastening keeps screw heads out of the walking surface. The result is a cleaner, smoother finish that looks better and is safer barefoot. Composite commonly uses clip systems; hidden solutions are also available for thermowood and larch depending on profile and system.

Ventilation tape and geotextile

• Ventilation tape between joist and board helps keep contact surfaces drier and reduces rot risk.
• Geotextile under the terrace helps control weeds while letting water through.

How much does terrace construction cost?

The final price mainly depends on three factors:

• chosen decking material (pressure-treated wood, larch, thermowood, composite)
• substructure and base (soil conditions, height, slopes)
• installation quality (frame rigidity, ventilation, fasteners)

The cheapest option is not always the best long-term value. A well-built terrace can last 20+ years without structural problems. For a precise quote based on your site and material choice, see our terrace construction service.

Frequently asked questions

Which decking material lasts the longest?

Durability depends on both material and installation. Thermowood and composite generally last longer, but properly maintained pressure-treated wood can also last a long time. The key is a rigid frame and good drying conditions (ventilation + drainage).

Is composite always better than wood?

Not always. Composite is very convenient and low-maintenance, but natural wood may be a better fit for appearance, feel or budget. The right choice depends on how you use the terrace and what you expect.

Is it worth hiring a specialist?

If you want a straight, stable, long-lasting result, it’s worth trusting terrace construction to an experienced team. See our terrace construction service and request a quote.