Timber Cladding Profiles Guide: Shadow Gap, Shiplap, Board-on-Board, Rainscreen & Secret Fixing Systems

5 March 2026 Leave a comment 329 Views Leave review

Timber cladding profiles determine far more than appearance. The board shape influences how rainwater drains from the façade, how joints create shadow lines across the building, how boards move through seasonal humidity cycles, and how easy installation becomes. Selecting the right cladding profile is therefore both an architectural and technical decision.

Across the UK, timber cladding is widely used on modern extensions, garden buildings, rural homes and contemporary architectural projects. Each profile has different strengths. Some prioritise rain protection and durability, while others create sharp modern lines or textured façades.

Understanding how each profile works helps ensure that the cladding system performs reliably over decades of exposure to wind, rain and seasonal temperature changes.

If you want a complete overview of timber cladding materials, façade construction and timber species used across UK projects, see the ultimate guide to timber cladding in the UK.


timber cladding profile comparison showing shiplap shadow gap tongue and groove and batten boards


Timber cladding profiles explained (quick guide)

Timber cladding profiles control how boards shed water, how joints form shadow lines and how the façade manages movement caused by seasonal moisture changes. The most common profiles used in the UK include shiplap, shadow gap, tongue and groove, batten cladding and rainscreen boards.

Best timber cladding profiles by project type

  • Modern houses and extensions: shadow gap cladding or rainscreen boards.
  • Garden rooms and studios: shiplap or tongue and groove boards.
  • Cabins and rustic buildings: loglap cladding.
  • Architectural façades: vertical batten or slatted cladding.
  • Coastal or exposed locations: ventilated rainscreen cladding systems.

Decision checklist for choosing a cladding profile

  • Does the profile shed water or rely on rainscreen ventilation?
  • Will the façade use visible screws or secret fixing systems?
  • How visible will board movement be within the design?
  • Is the building traditional or contemporary in style?
  • Will the timber be coated or allowed to weather naturally?

Modern timber façades usually combine stable timber boards with ventilated rainscreen construction to ensure long-term durability in the UK climate.

  • Shiplap cladding – overlapping boards designed to shed rainwater effectively.
  • Shadow gap cladding – modern boards creating crisp architectural shadow lines.
  • Tongue and groove cladding – interlocking boards forming a continuous surface.
  • Batten or slatted cladding – vertical timber battens producing strong shadow rhythm.
  • Loglap cladding – rounded boards often used on cabins and garden buildings.
  • Rainscreen cladding boards – ventilated façade systems designed for modern buildings.

Modern façades typically combine stable timber boards with ventilated rainscreen construction. The profile controls how boards overlap or separate, which directly affects drainage, ventilation and long-term durability.

Why timber cladding profiles matter

Timber cladding performs best when installed as part of a ventilated façade system. The outer timber boards provide the architectural finish while a breather membrane behind the cladding protects the structural wall.

A ventilated cavity between the cladding and the wall structure allows air to circulate. This airflow helps remove moisture that might pass behind the boards during heavy rainfall or condensation cycles.

The shape of the board joint determines how water behaves across the façade. Overlapping profiles such as shiplap provide strong rain shedding. Open-joint profiles such as batten cladding rely on rainscreen construction to ensure water drains safely behind the boards.

Because the UK climate is characterised by frequent rainfall and seasonal humidity, selecting a profile that supports effective drainage and ventilation is essential for long-term façade durability.

Modern timber cladding materials

While many timber species can be used externally, modern construction increasingly favours materials that provide improved dimensional stability and durability.

Many projects use façade systems based on exterior cladding panels combined with ventilated cavity construction to achieve long-lasting building envelopes.

Stable timber species are particularly important for modern cladding profiles where narrow joints or shadow lines must remain visually consistent. Thermally modified timber is widely used for this purpose.

ThermoWood cladding is commonly specified for contemporary façades because thermal modification reduces moisture absorption and improves dimensional stability. These properties help boards maintain consistent alignment and reduce visible movement over time.

Timber cladding profile comparison

Profile Typical Use Installation Direction Water Drainage Movement Sensitivity
Shiplap Traditional houses and garden rooms Horizontal Excellent Low
Shadow Gap Modern architecture Horizontal or vertical Good Medium
Tongue & Groove Cabins and interior walls Horizontal or vertical Moderate Medium
Batten Contemporary façades Vertical Good ventilation Medium
Loglap Cabins and sheds Horizontal Moderate Low
Rainscreen boards Modern buildings Vertical or horizontal Excellent Low


Download the standard timber cladding profile schedule

For architects and contractors who want a quick technical overview of the most common timber cladding profiles, we provide a downloadable profile schedule including dimensions and board profiles.

Download the timber cladding profiles schedule (PDF)


Shiplap timber cladding

shiplap timber cladding board profile overlapping rain shedding design


Shiplap cladding is one of the most widely used timber cladding profiles in the UK. Each board overlaps the board below it, creating a weather-resistant joint that sheds rainwater effectively.

This overlapping design prevents water from entering the joint between boards while still allowing boards to expand and contract naturally.

Shiplap boards are typically installed horizontally so rainwater flows down the façade rather than penetrating the joint between boards.

A detailed explanation of this profile and installation techniques can be found in shiplap cladding explained.

Shadow gap cladding


shadow gap timber cladding on modern UK house creating vertical shadow lines


Shadow gap cladding has become extremely popular in modern architecture. Instead of overlapping boards, the boards are installed with small consistent gaps between them.

These gaps create horizontal or vertical shadow lines that emphasise the geometry of the building.

Because the joints are visible, stable timber species are often selected to minimise movement and maintain consistent spacing throughout seasonal cycles.

Tongue and groove timber cladding


tongue and groove timber cladding profile showing interlocking board joint


Tongue and groove boards feature a projecting tongue on one edge and a matching groove on the opposite edge. When installed the boards interlock tightly together to form a continuous surface.

This profile creates a smooth uniform façade and is commonly used on interior timber walls and garden structures.

When used externally, proper ventilation behind the boards becomes particularly important to allow moisture to escape.

Batten and slatted timber cladding


vertical batten timber cladding facade used on modern architectural building


Batten cladding uses vertical timber battens fixed over backing boards or a membrane system to create a slatted façade.

The gaps between battens create strong shadow lines which give buildings a distinctive architectural appearance.

This style of cladding is widely used on modern extensions, commercial buildings and contemporary houses.

Loglap timber cladding

Loglap boards feature a rounded outer face designed to resemble traditional log construction.

Although the outer face is curved, the back of the board contains a tongue and groove joint allowing boards to interlock securely.

Loglap is commonly used on garden buildings, cabins and outdoor structures.

For installation guidance see loglap cladding explained.

Rainscreen timber cladding systems

Most modern timber façades use ventilated rainscreen construction. In this system the timber boards form the outer protective layer while a breather membrane behind the cladding provides the secondary weather barrier.

A ventilated cavity allows airflow behind the boards, helping remove moisture and preventing water from becoming trapped within the wall system.

Rainscreen construction significantly improves the durability of timber façades because water can drain and evaporate quickly.

A deeper explanation of this system can be found in rainscreen cladding explained.


timber rainscreen cladding wall on modern building


Typical rainscreen wall build-up

  • Timber cladding boards
  • Ventilated cavity
  • Timber battens
  • Breather membrane
  • Structural wall or sheathing board
  • Insulation layer

Secret fixing systems for timber cladding

Secret fixing systems allow timber cladding boards to be installed without visible screws on the surface of the façade. Instead of fixing through the face of the board, the boards are secured using concealed clips or angled screws placed within the board joint.

This installation method produces a cleaner architectural finish because the timber surface remains uninterrupted by visible fixings. It also protects screws from direct weather exposure which can improve long-term durability.


secret fixing system for timber cladding boards using concealed clips


Common concealed fixing methods

  • Clip fixing systems – metal clips secure boards to battens while allowing expansion and contraction.
  • Angled screw fixing – screws are driven through the edge of the board and hidden by the next board.
  • Groove fixing systems – specialist boards include concealed grooves designed for hidden clips.
  • Panelised cladding systems – boards are pre-assembled into panels and installed as complete façade sections.

Secret fixing systems are commonly used with modern profiles such as shadow gap boards and rainscreen cladding systems where architects want uninterrupted timber surfaces.

However, concealed fixing does not eliminate timber movement. Boards still expand and contract depending on humidity and temperature. Correct board spacing and ventilation behind the façade remain essential to prevent distortion or splitting.

In some applications face fixing with visible screws may still be preferable, particularly when large boards are used or where maximum structural strength is required.

Best timber cladding profiles by project type

Different building types often favour different cladding profiles.

Project Type Recommended Profiles
Modern houses Shadow gap or rainscreen cladding
Garden rooms Shiplap or tongue and groove
Cabins Loglap or tongue and groove
Architectural façades Batten or shadow gap
Coastal homes Rainscreen systems

Timber cladding maintenance and weathering

Timber cladding naturally changes appearance over time due to sunlight and weather exposure.

Many timber species weather to a silver-grey colour when left untreated. This natural weathering process does not necessarily reduce durability but it does alter the appearance of the façade.

Some homeowners prefer to apply oils or stains to maintain colour consistency. These finishes typically require periodic maintenance as UV exposure gradually breaks down protective coatings.

Regular inspection and cleaning can help maintain the appearance and performance of timber cladding over time.


modern UK house with vertical timber cladding facade

Related timber cladding guides


FAQ: timber cladding profiles

What timber cladding profile lasts the longest?

Durability depends on timber species and installation method rather than the profile alone. Profiles installed within ventilated rainscreen systems typically perform best because they allow moisture to drain and evaporate.

What is the most common timber cladding profile in the UK?

Shiplap cladding remains one of the most widely used profiles because its overlapping design sheds water efficiently.

Which cladding profile is best for modern houses?

Shadow gap and batten cladding are widely used on contemporary architecture because they create clean geometric shadow lines.

Can timber cladding be installed vertically?

Yes. Many cladding profiles can be installed vertically or horizontally depending on architectural design and drainage requirements.

What is rainscreen timber cladding?

Rainscreen cladding is a ventilated façade system where the timber boards act as the outer protective layer while a cavity behind the boards allows moisture to drain and evaporate.

Do timber cladding boards need ventilation?

Yes. Ventilation behind cladding boards helps remove moisture and prevents long-term water accumulation within the wall structure.

What is secret fixing?

Secret fixing is an installation method where screws or clips are hidden within the board profile rather than visible on the surface.

What timber cladding profile is easiest to install?

Shiplap cladding is generally considered one of the easiest profiles to install because the overlapping boards naturally shed water and allow minor alignment adjustments. The simple joint design makes installation more forgiving compared with modern open-joint systems such as shadow gap cladding, which require precise spacing and accurate fixing to maintain consistent lines across the façade.

What cladding profile is best for heavy rain?

Overlapping cladding profiles such as shiplap provide the strongest protection against rain because the joint design allows water to drain away from the façade. However, modern rainscreen cladding systems also perform extremely well in wet climates because the ventilated cavity behind the boards allows moisture to drain and evaporate quickly.

Which timber cladding profile is best for extensions?

Modern house extensions often use shadow gap or batten cladding profiles because they create clean architectural lines and emphasise the geometry of the building. These profiles work particularly well when combined with thermally modified timber or other stable species that minimise movement.

What timber cladding profile lasts the longest?

The lifespan of timber cladding depends more on installation method and timber species than on the profile alone. Profiles installed within ventilated rainscreen systems typically last longer because they allow moisture to drain and evaporate effectively. Proper ventilation, durable timber species and regular inspection all contribute to long service life.

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