✅ Responsibly manufactured in Lempäälä
✅ Completely natural and safe product
✅ Colorful with subtle variations, weathers to an elegant gray
✅ Naturally strong and highly rot-resistant
✅ No surface treatment needed for outdoor use, nearly maintenance-free
✅ Raw material from PEFC-certified sources

Our product uses Douglas fir, a naturally highly rot-resistant softwood. Its subtly reddish tones gradually develop into a beautiful silver-gray with exposure to the elements. Strong and durable, Douglas fir requires no surface treatment outdoors and is almost maintenance-free. Our Douglas fir products are responsibly produced, environmentally friendly, and sourced from PEFC-certified forests.

Product information

Product measurements

Product features

Sustainability

Grading rules

You can download the grading rules applied in the manufacture of this product here: Douglas Fir

Minimum order size

Please note that we deliver our products in bundles. Bundle size is indicated together with stock information on top right corner.

Installation

A well-planned and carefully installed deck lasts for decades. The key is to let water drain away and air circulate under the deck. If you're unsure about any step, ask a professional installer for help.

Before installation

Store the boards correctly.

• Protect the boards from direct sunlight and rain before installation.
• Store the boards horizontally on a level surface in their unopened packs.
• Raise the packs at least 75 mm off the ground so that air can circulate underneath.
• Sunlight and moisture together may start to turn the boards gray in places even before installation. The color evens out after installation.

Plan your deck.

• Plan the direction of the boards and the position of any joints in advance. They affect how the frame is built.
• Allow extra length for cutting. The stated product length is not an exact measurement, so choose boards that are at least 5 cm longer than you need.
• Where possible, lay the boards across the main walking direction. This reduces the risk of slipping.
• Check your local building regulations. Your deck may require a permit.

Base and frame

Prepare the ground.

1. Remove the topsoil and level the surface.
2. Spread a layer of coarse gravel or crushed stone about 15 cm thick and compact it.
3. Add a layer of fine gravel or sand about 5 cm thick on top.
4. Cover the surface with a water-permeable weed membrane to keep plants from growing under the deck.
5. Slope the ground at least 2% away from the building so that water doesn't collect under the deck.

Leave a ventilation space under the deck. There must be at least 100 mm of space between the frame and the ground. If the deck is built on a concrete slab or paving, 50 mm is enough.

Build a durable frame.

• Use pressure-treated or naturally durable timber suitable for use class 3.2 for the frame.
• Support the boards and the frame at a minimum of three points.
• Slope the deck 1–2% away from the building so that rainwater runs off and doesn't form puddles.
• Leave a gap of at least 20 mm between the frame and the wall of the building.
• Choose the joist spacing according to the board thickness:
  • 28 mm board: 400–600 mm
  • 45 mm board: 600–800 mm
• Install two joists side by side where board ends meet, so that each board end has its own support.
• Cover the top of the joists with joist tape or use spacers. They keep moisture from rising and improve ventilation between the boards and the frame.

Laying the decking boards

Choose the visible face. Install the boards with the better side facing up. Also aim to keep the heart side as far from the visible surface as possible. This reduces cracking.

Sort the boards. Arrange the boards so that the knots are spread evenly across the whole deck.

Leave a wide enough gap. Boards stored out of the weather swell once they get wet after installation. That's why you need a wide enough gap between the boards.

• Uncovered deck or pier: at least 8 mm
• Covered deck: 5 mm

These gaps are guidelines for a 145 mm wide board. If you use a wider board, increase the gap. Spacers help you keep the gaps even.

Check the alignment. Measure at regular intervals to make sure the boards stay on the planned line.

Fastening

1. Use the right screws. Fasten the boards with countersunk A2 stainless steel screws. By the sea or near a swimming pool, use acid-resistant A4 stainless steel screws.
2. Choose the screw size according to the board thickness.
   • 28 mm board: 5 x 70 mm
   • 45 mm board: 6 x 120 mm
3. Fasten each board with two screws at every joist.
4. Keep the right distances. Place the screws at least 20 mm from the edge of the board and at least 50 mm from the end of the board.
5. Pre-drill the screw holes, especially at the ends of the boards. This keeps the boards from cracking.
6. Drive the screws to the right depth. The screw head should sit flush with the board surface or no more than 2 mm below it. A protruding head can be a tripping hazard, and water collects in a hole that is too deep.

Finishing

• Leave a gap of at least 20 mm between the deck and other structures so that air can circulate and rainwater can drain away.
• If you clad the sides of the deck, leave at least half of each side open for ventilation.
• Spread gravel around the deck. It keeps plants away, improves ventilation and makes maintenance easier.

Good to know

Boards containing heartwood may develop cracks over time. Cracking can't be avoided completely, as it is a natural characteristic of all wood species. The cracks do not affect the durability of the deck.

Surface treatment

Our decking boards don't need any surface treatment. The wood is naturally rot-resistant and dense, so it withstands Finnish weather conditions without oil or paint. That's why we don't recommend any surface treatment at all.

Turning gray

An untreated deck turns a beautiful silvery gray from rain and the sun's UV radiation. Depending on conditions, this takes about 2–3 years.

In covered and other sheltered spots, the wood turns gray more slowly. The same applies to areas under furniture, planters or rugs. This is why the surface may look patchy at first. The difference evens out over time, and you can speed this up by moving planters and rugs around during the first few years.

If you want to influence the color

• Slowing down the graying: You can slow down the graying by treating the deck with a clear or tinted deck oil. Oil soaks into dense wood slowly, and the treatment must be repeated much more often than on spruce. Without repeated treatments, the natural graying of the wood can't be prevented.
• Speeding up the graying: Iron sulfate (green vitriol) makes the deck turn gray quickly and evenly. Brush or spray a mixture of iron sulfate and water in a ratio of 1:10 onto the surface twice. The graying starts once the surface is exposed to daylight, and the final color develops in about 7–14 days.

Maintenance

An untreated deck is almost maintenance-free. When you keep it clean and the structures in good condition, your deck lasts for decades.

Check your deck once a year

• Make sure all the screws are in place, and tighten or replace any loose ones.
• Clear leaves and debris from the gaps between the boards so that water can drain away.
• Make sure air can circulate under the deck and that no debris or plants build up there.

Splintering

Especially on uncovered decks and piers, some boards may start to splinter after about a year. This is natural for wood, and the splinters are easy to remove:

• sand the surface along the board with 180-grit sandpaper, or
• scrape the surface with a cabinet scraper.

Good to know

• Small cracks: Over time, sunlight and changes in moisture and temperature may cause small cracks in the wood surface. This is a natural characteristic of wood and does not affect the durability of the deck.
• Dark marks around fasteners: Douglas fir and larch are rich in natural extractives, which can react with galvanized fasteners and leave dark streaks around them. As the wood turns gray, these streaks become hard to notice. That's why we recommend stainless steel screws for fastening the deck.

Thorough cleaning

Give your deck a thorough clean once or twice a year.

1. Choose a cool moment. If you use a cleaning product, wash the deck when it's not in direct sunlight. This keeps the cleaning product from drying on the surface too quickly.
2. Brush off dust and debris with a long-handled brush. Brush the edges of the deck and other structures too.
3. Wet the surface with warm water. Warm water opens the pores of the wood.
4. Wash with water and an all-purpose cleaner, using a soft brush, such as a scrub brush, or a scouring sponge. Brush along the grain of the wood.
5. Rinse with cold water. Cold water closes the pores of the wood.
6. Let the deck dry thoroughly.

Avoid cleaning products that contain chlorine. Chlorine can soak into the wood and be released into the air when the deck heats up in the sun.

If your deck is oiled

If you have oiled your deck for its looks, oil it after cleaning, once the wood is completely dry.

Choose the right weather

• Oil on a dry, overcast day after a few days that have dried out the wood. The moisture content of the wood must be below 20%.
• Avoid direct sunlight. On a surface that is too hot, the oil doesn't have time to soak in evenly.
• Start only once the morning dew has dried, and stop well before the evening dew settles.
• Don't oil if rain is forecast.
• Check the right application temperature in the oil manufacturer's instructions.

How to oil

1. Apply a thin layer of oil with a brush or deck oil pad so that all the oil soaks into the wood.
2. Work evenly, one board at a time from end to end. This keeps lap marks from forming.
3. Wipe off any oil that hasn't soaked in.
4. Let it dry thoroughly.

A Durable and Natural Choice for Outdoor Construction

Wood products made from some of nature’s most durable species are ideal for decking and pier structures. Boards are suitable for decking surfaces and pier planking, while posts can be used, for example, as railing posts. For privacy screens and other decorative structures, the range includes various slats and slanted battens. Lauta.fi’s outdoor construction products are also used in public projects, such as stairs, fences, railings, pathway surfacing, landscaping solutions, and park benches.

Douglas fir, with its beautiful grain and rich color variation, is suitable for both interior cladding and versatile outdoor construction. Thanks to its excellent rot resistance, it may not require any surface treatment at all. However, for aesthetic reasons, surface treatment can be applied to slow the wood’s natural greying, especially on decks. The surface can also be oiled if desired, but without regular maintenance, the wood’s natural aging cannot be prevented.

Lauta.fi delivers product sample pieces to both consumer customers and professionals, such as architects, interior architects and designers, construction industry and procurement professionals.

If you are interested in ordering one or more sample pieces, please contact our sales department via email lauta@lauta.fi or phone +358 3 3123 6000 (On weekdays 8-16).