Installation

Thermosticks cladding offers a durable and aesthetically pleasing solution for exterior cladding. Made through a process of thermal modification, Thermowood provides enhanced resistance to decay and weather, making it an ideal choice for various climatic conditions. This guide walks you through the necessary steps and considerations for the proper installation of Thermosticks cladding.

Tools and materials

Before beginning the installation process, gather all necessary tools and materials. Proper preparation ensures a smoother installation and helps avoid potential delays.

Materials

Thermosticks profiles: Select the appropriate profile based on your project's design and the intended orientation.
Support battens: Treated wood, naturally durable species, or metal depending on project needs.
Fixing system: Self-drilling screws suitable for the materials in use (wood or metal). Stainless steel screws (AISI 304) are recommended for durability. 16-gauge finish nails in stainless steel may also be used.
Breathable waterproof membrane: Protects the support wall while allowing moisture to escape.
Sealing tape: Compatible with the breathable membrane for sealing joints and overlaps.
Insect mesh (optional): Prevents insects and small rodents from entering the cavity behind the siding.
Finish coating (optional): Suitable for exterior wood to protect Thermowood from UV radiation and moisture.

Tools

Measuring: measuring tape, ruler, laser level, precision level, carpenter's square

Cutting: circular saw, miter saw, clamps, utility knife

Fixing: drill with twist drill bits, screwdriver or nail gun with depth control

Marking: pencil, chalk line marker

[ Tools & materials layout ] Flat lay of installation tools and fasteners on a workbench.

Personal protective equipment. Safety is paramount during the installation process. Ensure you and your team are equipped with protective glasses, a dust mask (with active carbon filter recommended, particularly when cutting or sanding), work gloves, safety footwear, a safety helmet, and fall protection equipment when working at heights.

Handling and storage

Proper handling and storage of Thermosticks cladding is crucial to maintaining the integrity and quality of the siding material. Incorrect storage can lead to warping, discoloration, or other forms of damage.

Storing on the construction site

Dry, ventilated storage. Store Thermosticks cladding in a dry, well-ventilated area, protected from direct sunlight and precipitation. Exposure to UV rays can cause the wood to change color prematurely.
Covering. Keep Thermosticks profiles completely and tightly covered with UV-protective wraps. It's best to store them in their original packaging until installation.
Elevation. Elevate packages at least 3 inches off the ground. Use battens or pallets to create an even base, allowing airflow beneath.
Flat surface. Place material on a flat, stable surface to avoid bending or warping. Ensure support points are evenly distributed.

Handling with care

Secure and stable placement. Avoid placing heavy objects on top of the profiles.
Gentle handling. Avoid knocking profiles against hard surfaces tongue-and-groove profiles are particularly susceptible to edge damage.

Pre-installation considerations

Acclimatization. Allow Thermowood to acclimate to the local climate by storing on-site for a few days before installation.
Inspect for damage. Before installation, inspect for any signs of damage or warping. Address issues promptly to avoid compromising the quality of the installation.

[ On-site storage ] Thermosticks bundles properly stacked, wrapped, and elevated on pallets.

Installation orientation

The orientation of the siding plays a significant role in both the aesthetic appeal and longevity of the installation. The choice between vertical and horizontal orientation affects water drainage and overall performance.

Vertical orientation

Often preferred for its ability to efficiently shed water, reducing the risk of moisture accumulation and potential damage. It provides a clean, elongated look ideal for modern architectural designs.

Horizontal orientation

Offers a classic, timeless appearance and is easier to install. However, it may be more susceptible to water infiltration if not properly sealed, especially in areas with high rainfall.

The profile you choose will also impact the feasible installation orientations. Some profiles are better suited for specific orientations, so consider both visual design and practical performance when selecting the installation direction.

[ Vertical vs horizontal comparison ] Two buildings side by side showing the same profile in vertical and horizontal applications.

Support battens and fixing systems

Depending on the application and orientation, you can use a rain-screen system with support battens to create an air cavity behind the material. When siding is oriented vertically and there's no stud framing to fasten the material to, a rain-screen installation including horizontal battens and gaps for drainage behind the battens is recommended. This creates a strong substrate behind the cladding.

In horizontal applications where an exterior vapor barrier is used, Thermowood cladding may be applied directly over the vapor barrier if necessary. However, when possible, an air gap is always recommended.

[ Batten system diagram ] Cross-section showing wall, membrane, batten, and cladding relationship.

Why the air cavity matters. The air cavity behind Thermosticks cladding allows for proper ventilation, helping to balance moisture content within the siding and the underlying structure. A cavity of at least 1 inch in depth is recommended to facilitate adequate airflow and moisture evaporation preventing the moisture buildup that can lead to decay and other structural issues over time.

Before installing support battens, apply a waterproof breathable membrane to protect the support wall.

Wooden support battens

Wooden battens should be made from treated wood or a naturally durable species to withstand outdoor conditions. Proper alignment and spacing are crucial to ensure a consistent air cavity. Use stainless steel screws or nails, which resist corrosion and ensure long-term stability.

Metal support battens

Typically made from aluminum, metal support battens are used in scenarios requiring higher structural stability or in environments where wood might be prone to decay. They're usually secured to the structure using brackets and screws.

Horizontal siding: Maintain a minimum 1-inch ventilation gap. Use vertical support battens spaced no more than 24 inches apart.
Vertical siding: Also maintain a 1-inch ventilation gap. Use a double layer of battens, with vertical battens spaced 24 inches apart. Horizontal battens should be angled slightly (15°) toward the interior of the cavity to promote water drainage.

General installation instructions

General process

1. Inspect wall preparation. Before beginning, conduct a thorough inspection. Ensure the waterproof breathable membrane covers the entire wall surface and is intact with no visible damage or gaps. Verify that battens are securely fastened and evenly spaced, maintaining the required 1-inch ventilation gap. Confirm all aspects of wall preparation comply with applicable building codes.

2. Start siding installation. Begin from one corner, fixing each board securely to the vertical furring strips using stainless steel screws or nails.

3. Check alignment. Continuously check the alignment of siding boards to maintain a straight and even appearance.

4. Finish corners and edges. Carefully trim and secure the boards at corners and edges, ensuring they fit snugly and are properly sealed.

5. Inspect and adjust. After installation, inspect for any gaps or misalignments, and adjust as needed.

[ Installation in progress ] Contractor installing Thermosticks boards on a vertical rain-screen assembly.

How to secure Thermosticks cladding

Use stainless steel fasteners. Self-drilling stainless steel screws, AISI 304 or higher, to prevent corrosion. 16-gauge finish nails in stainless steel may also be used.
Screw placement. For profiles less than 5.5 inches wide, use one screw per intersection with the batten. For profiles wider than 5.5 inches, use two screws per intersection.
Pre-drill holes. Pre-drill when placing screws within 3 inches of the end of profiles to prevent splitting. Hole diameter should be 50-80% of the screw diameter.
Screw depth. Screw heads should be flush with the cladding surface. Overdriving causes splits, surface staining, or moisture traps. Underdriving leaves the screws exposed.
Support battens. Each cladding profile should be fastened to at least three battens for sufficient support and to prevent warping.
Screw length. Should be more than twice the thickness of the cladding profile, but less than the combined thickness of the facade and support battens.

Vertical tongue-and-groove installation

Thermosticks profiles wider than 5-1/2 inches need two stainless steel screws or nails per intersection with support battens. For profiles only requiring one screw, face nailing may be avoided.

When using face nailing with profiles that have surface grooves (like TG-Triple), keep screw head diameter below the width of the groove at its narrowest point.

When fixing Thermosticks profiles designed for hidden nailing (HN), position screws at the indicated position in the profile drawing.

[ Vertical profile diagrams ] TG-Triple Vertical VN, TG-I Vertical VN, TG-I Vertical HN cross-sections showing screw placement.

Top edge: Leave a gap of at least 3/4 inch between the top edge of the siding and any overhangs, eaves, or flashings. This space allows for adequate ventilation behind the siding.

Bottom edge: The bottom edge should be at least 12 inches above the ground in areas prone to rainwater splashing. If the area beneath is covered with gravel or other permeable materials, this distance can be reduced to 8 inches.

Angled cuts: Consider cutting the ends of siding boards at a 30° angle where they meet the bottom edge. This encourages moisture to drip off the ends more easily, reducing the risk of water being trapped against the wood.

Horizontal tongue-and-groove installation

Only use Thermosticks profiles designed for horizontal application. Avoid profiles with horizontal surfaces that can accumulate rainwater.

Thermosticks cladding wider than 5-1/2 inches needs two stainless steel screws per intersection with strips. Ensure screw heads are flush with the cladding surface.

Additional points to consider

Design the cladding to allow rainwater to drain quickly and easily. Avoid horizontal surfaces where water can accumulate.
Seal the end grains of boards wherever applicable (end grain, ends of profiles, corners) and after cutting to prevent moisture absorption.
Ensure screws are flush with the surface to avoid splits and moisture traps.
Keep the installation clean and even to promote uniform weathering.

[ Horizontal profile diagram ] Cross-section of horizontal tongue-and-groove installation with screw locations indicated.

Corner details

Both 45° and 90° corner configurations are supported. Exterior corners may use either a mitered (45°) return or a 90° butt joint with a corner trim. Interior corners follow the same principle, mitered for a seamless line, or butted for a simpler fabrication.

Regardless of corner type, seal end grains at the cut and maintain the air cavity continuity around the corner. Don't block the ventilation path at the change of direction.

[ Corner detail drawings ] 45° and 90° exterior and interior corner configurations in plan view.

Staining and finishing strategies

Staining and finishing your Thermosticks cladding plays a significant role in both appearance and durability. Different strategies can enhance the natural aging of the wood, maintain its original appearance, or achieve a completely different finish through painting. The approaches below let you select the best method for your preferred outcome.

Natural aging look

If you prefer the natural weathered look as Thermowood ages:

Allow natural greying. Thermowood fades from its original dark-brown hue to a silver-grey tone due to sunlight exposure. This process typically begins within 3 to 6 months.
Minimal treatment required. Leave the wood untreated. To ensure even weathering, avoid applying coatings that could block the natural aging process.
Consider pre-greyed finishes. For a consistent aged appearance from the start, consider a pre-greyed finish that accelerates the natural patina. See our finishing options page for our Valhalla accelerated-silvering service.

[ Naturally aged facade ] Thermowood building at 2-3 years showing the settled silver-grey patina.

Maintain the original brown

To keep the rich, warm color intact and protect it from the elements:

Apply a UV-resistant coating. Use a transparent or translucent finish with UV protection to prevent fading and maintain the original appearance.
Reapply coating periodically. Depending on the climate and exposure, you may need to reapply every few years.
Surface preparation. Before applying any finish, ensure the wood is clean and dry. Lightly moisten the surface before applying stain to open the pores and enhance absorption.

Our Proluxe in-house finishing service (described on our finishing options page) handles this application for you before your boards ship.

[ Freshly finished Thermowood ] Close-up of a Proluxe-treated board showing the rich preserved brown tone.

Painting

For a bold, opaque finish that completely covers the wood grain:

Choose high-quality paint. Use an opaque exterior paint suitable for wood, acrylic or silicate. These are breathable and allow moisture to escape, which is crucial for maintaining the wood's integrity.
Prepare the surface. Ensure the wood is clean, dry, and free from any previous finishes that could interfere with adhesion.
Apply primer if necessary. Depending on the paint chosen, a primer may be needed for even coverage and better adhesion.
Multiple coats for durability. Apply in multiple thin coats, allowing each to dry fully before applying the next.

By choosing the right finishing strategy, you can enhance the natural beauty of Thermosticks cladding, maintain its original look, or achieve a completely different aesthetic, all while protecting the wood from the elements.

[ Painted Thermowood example ] A painted Thermowood facade showing opaque finish application.

Questions about your specific installation?

Email sales@stickssupply.com or call 864-202-6710. For warranty-related inquiries, reach our warranty team at warranty@stickssupply.com.

Need a printable copy? Download the complete Thermosticks Installation Guide as a PDF.

These instructions are Thermosticks' recommendations and should be used alongside applicable regulations, building codes, and best practices, whether local or not. Any drawings included in this guide are intended for reference purposes only.