Hardwood Decking Joists & Construction Beams

Buy Hardwood Decking Joists and Construction Beams Online

A reliable decking structure starts with a properly designed foundation. Hardwood decking joists and construction beams provide support beneath decking boards, helping to create a stable and durable outdoor terrace.

Whether you are building a new garden deck, replacing an existing timber subframe or planning a larger outdoor construction project, choosing suitable supporting timber is essential.

At Intergard, our range includes 45 x 70 mm hardwood construction beams, 60 x 60 mm hardwood posts and PVC support accessories.

These products can be used in suitable decking substructures, subject to the required structural design, timber properties and installation conditions.

Explore our complete decking range, including hardwood decking boards, Douglas decking and composite decking.

What Are Hardwood Decking Joists?

Decking joists are supporting timber members installed beneath decking boards. They form part of the subframe that transfers loads from the decking surface to the supporting foundations.

Hardwood joists may also be described as decking bearers, subframe beams, decking support timbers or construction battens, depending on their intended application.

The supporting structure must be designed to accommodate the expected loads, span distances and environmental conditions.

Choosing suitable hardwood construction beams can help provide a reliable foundation for your decking project.

Why Choose Hardwood Construction Beams for Decking?

1. Strong Supporting Structure

Hardwood construction beams can provide suitable support for timber decking when the timber species, grade and dimensions meet the structural requirements.

A correctly designed subframe helps distribute loads and maintain a stable decking surface.

2. Suitable for Outdoor Construction

Appropriately specified hardwood can be suitable for outdoor applications, including decking subframes and garden structures.

Actual durability depends on the timber species, heartwood content, exposure conditions and installation.

3. Support for Different Decking Materials

Hardwood joists may be used beneath suitable hardwood, softwood or composite decking systems, provided the decking manufacturer's installation requirements are followed.

4. Improved Drainage and Ventilation

A properly designed subframe helps create space beneath decking boards for drainage and ventilation.

Keeping timber away from standing water and prolonged moisture exposure can help improve long-term performance.

5. Practical Timber Dimensions

Our listed hardwood construction beams measure 45 x 70 mm and are available in 300 cm lengths.

We also offer 60 x 60 mm hardwood posts in 150 cm lengths for suitable supporting applications.

6. Suitable for DIY and Professional Projects

Hardwood construction timber can be used by experienced DIY installers and professional contractors, provided the supporting structure is correctly designed and installed.

Hardwood Construction Beams and Supports Available at Intergard

Our category currently contains three listed products.

Product	Dimensions	Typical application
Hardwood construction beam	45 x 70 x 3000 mm	Suitable decking joist or subframe applications
Hardwood square post	60 x 60 x 1500 mm	Suitable garden construction or supporting applications
PVC garden shed support	See product specifications	Supporting or spacing applications where compatible

Check the individual product listings for exact specifications, current prices, availability and delivery information.

Hardwood Decking Joists 45 x 70 mm

Our 45 x 70 mm hardwood construction beams are listed in 300 cm lengths.

This rectangular timber profile can be considered for suitable decking subframes, subject to structural requirements and installation conditions.

The beam dimensions are:

• Thickness: 45 mm.
• Height: 70 mm.
• Length: 3000 mm.
• Material: hardwood.

The correct orientation, permissible span and joist spacing depend on the timber's structural properties, support arrangement and expected loads.

For load-bearing applications, confirm the timber grade and obtain appropriate structural guidance where necessary.

Hardwood Square Posts 60 x 60 mm

Our 60 x 60 mm hardwood square posts are available in 150 cm lengths.

They may be suitable for various garden construction and supporting applications where their dimensions and timber properties meet the project requirements.

When using hardwood posts as part of a decking support system, the foundations, connections and structural loads must be considered.

Do not assume that the posts are suitable for every raised decking application without checking the relevant structural requirements.

PVC Supports for Garden Structures

Our range also includes a PVC support product listed as a garden shed support.

Suitable supports or spacers may help separate timber from certain supporting surfaces, depending on the product's design and intended application.

Always verify the support's load capacity, dimensions and compatibility before using it beneath a decking structure.

Hardwood vs Softwood Decking Joists

Both hardwood and softwood can be used for decking subframes when correctly specified.

Feature	Hardwood joists	Treated softwood joists
Material	Hardwood timber	Preservative-treated softwood
Density	Varies by species, often relatively high	Generally lower than dense tropical hardwood
Natural durability	Depends on species and heartwood content	Depends on preservative treatment and use class
Workability	Dense species may require predrilling	Generally easier to cut and drill
Structural suitability	Depends on grade, dimensions and spans	Depends on grade, dimensions and spans
Maintenance	Regular inspection	Regular inspection

The best material depends on the decking system, exposure conditions, budget and structural requirements.

Can Hardwood Joists Be Used with Different Decking Boards?

Hardwood Decking Boards

Hardwood joists may be suitable beneath tropical hardwood decking boards, provided the supporting structure and fixings are correctly specified.

Explore our Bangkirai decking, Massaranduba decking and Kapur decking.

Douglas Decking Boards

Hardwood joists may also be considered beneath suitable Douglas decking boards when the installation requirements are met.

Explore our Douglas decking boards.

Pine Decking Boards

Hardwood joists may be used beneath suitable pressure-treated pine decking systems, provided the materials and fixings are compatible.

Explore our pine decking boards.

Composite Decking Boards

Composite decking requires a subframe that complies with the decking manufacturer's installation instructions.

Hardwood joists should only be used where they meet the composite decking system's structural and fixing requirements.

Explore our composite decking boards.

How Far Apart Should Hardwood Decking Joists Be?

The correct joist spacing depends on several factors, including:

• Decking board material and thickness.
• Timber grade and structural properties.
• Expected loads and intended use.
• Joist dimensions and span.
• Supporting foundations and connections.
• The decking manufacturer's installation requirements.

Some domestic decking systems use joist centres in the region of 300–400 mm, but this is not a universal specification.

The correct spacing for your project must be confirmed using the relevant decking and structural requirements.

How Many Hardwood Joists Do You Need?

Before ordering, calculate the size of your decking area and plan the supporting structure.

Example: Joist Layout for a 20 m² Terrace

Suppose your terrace measures 5 metres by 4 metres.

If the decking system permits a joist spacing of 400 mm centre to centre, the number of joist lines across a 4-metre width would be:

• Deck width: 4 metres.
• Illustrative joist spacing: 0.40 metres.
• Number of intervals: 4 / 0.40 = 10.
• Number of joist lines: 11, including both outer edges.
• For joist lines running 5 metres long: 11 x 5 = 55 linear metres of joists.

This is an illustrative layout calculation, not a structural design or final cutting list.

Additional timber may be required for perimeter framing, intermediate supports, joints, blocking and other structural details.

With 3-metre beams, the number of pieces depends on the permitted support and joint positions. Do not assume that joining two beams creates a structurally suitable continuous span.

How to Build a Hardwood Decking Subframe in 8 Steps

A correctly designed decking subframe is essential for a stable and durable terrace. The following steps provide general guidance for suitable ground-level decking projects.

Step 1: Measure and Plan the Deck

Measure the installation area and determine the deck dimensions, height, board direction and supporting layout.

Step 2: Assess the Ground Conditions

Check that the ground or supporting surface is suitable for the proposed structure.

Determine the required foundations and drainage arrangements.

Step 3: Plan the Joist Layout

Calculate the required joist spacing based on the selected decking boards and structural requirements.

Identify the positions of supports, joints and perimeter framing.

Step 4: Install Suitable Foundations or Supports

Install correctly specified foundations or structural supports on a stable base.

Where compatible, suitable spacers or support products may help separate timber from supporting surfaces.

Step 5: Position the Hardwood Construction Beams

Place the hardwood joists according to the planned layout and required orientation.

Ensure that the joists are adequately supported and correctly aligned.

Step 6: Secure the Supporting Structure

Use suitable structural connections and corrosion-resistant fixings compatible with the timber and installation conditions.

Predrill dense hardwood where required to reduce the risk of splitting.

Step 7: Provide Drainage and Ventilation

Ensure that rainwater can drain away and that sufficient ventilation is maintained beneath the decking.

Avoid prolonged contact between untreated timber and standing water.

Step 8: Install the Decking Boards

Once the subframe is complete and inspected, install the decking boards according to the manufacturer's instructions.

Use suitable decking screws or approved fixing systems.

How to Protect Hardwood Decking Joists Against Moisture

Even naturally durable hardwood benefits from good construction detailing.

Provide Effective Drainage

Ensure rainwater can drain away from the decking structure and supporting surfaces.

Maintain Ventilation

Allow sufficient airflow beneath the decking to reduce prolonged moisture accumulation.

Avoid Standing Water

Do not position timber where water can remain trapped for extended periods.

Use Suitable Fixings

Choose corrosion-resistant fixings compatible with the hardwood species and environmental conditions.

Inspect the Structure

Periodically check the condition of the joists, posts, connections and supports.

How Long Do Hardwood Decking Joists Last?

Hardwood decking joists can provide many years of outdoor service when correctly specified, installed and maintained.

The original Intergard product information refers to durability class I and an indicative lifespan of approximately 25–35 years with proper ventilation.

However, these claims cannot be applied automatically to every hardwood species or product.

Actual service life depends on:

• The exact hardwood species.
• The proportion of heartwood and sapwood.
• Timber grade and product quality.
• Exposure to moisture and biological deterioration.
• Drainage and ventilation.
• Correct structural design and installation.

For projects requiring a specified durability class or service life, request the relevant product documentation before ordering.

Common Mistakes to Avoid with Decking Subframes

Using Joists Without Checking Structural Requirements

Joist dimensions alone do not establish permissible spans or load capacity.

Incorrect Joist Spacing

Excessive spacing can cause unwanted movement or deflection in the decking boards.

Poor Drainage

Standing water can affect the long-term performance of the timber and supporting structure.

Insufficient Ventilation

Inadequate airflow can allow moisture to accumulate beneath the decking.

Using Unsuitable Fixings

Incorrect fixings may corrode or fail under outdoor exposure conditions.

Ignoring Support and Joint Positions

Timber joints and supporting beams must be positioned and connected according to the structural design.

Frequently Asked Questions About Hardwood Decking Joists

What are hardwood decking joists?

Hardwood decking joists are supporting timber members installed beneath decking boards. They form part of the structure that transfers loads from the decking surface to the foundations.

What size hardwood construction beams does Intergard sell?

Our listed hardwood construction beams measure 45 x 70 x 3000 mm. We also offer hardwood square posts measuring 60 x 60 x 1500 mm.

Can hardwood joists be used under composite decking?

Hardwood joists may be suitable for certain composite decking systems, provided they comply with the decking manufacturer's structural and fixing requirements.

How far apart should decking joists be?

The correct spacing depends on the decking board material, thickness, expected loads and supporting structure. Always follow the manufacturer's installation specifications.

Do hardwood decking joists need ventilation?

Yes. Adequate ventilation and drainage help reduce prolonged moisture exposure and support the long-term performance of the timber structure.

How long do hardwood decking joists last?

Service life depends on the timber species, quality, installation and environmental conditions. Appropriately specified hardwood can provide many years of service when correctly installed and maintained.

Buy Hardwood Construction Beams from Intergard

Whether you are building a new garden terrace, replacing an existing decking subframe or planning a professional outdoor construction project, Intergard hardwood decking joists and construction beams provide practical options for suitable supporting structures.

Choose from 45 x 70 x 3000 mm hardwood beams, 60 x 60 x 1500 mm hardwood posts and compatible support accessories.

Complete your project with suitable decking screws and decking boards from our garden decking range.

Wholesale Hardwood Construction Beams for Trade Customers

Intergard has been an importer and wholesaler since 1997. We supply garden timber, decking materials and outdoor building products to timber merchants, garden centres, retailers, contractors and other professional customers throughout Europe.

Looking to buy hardwood construction beams wholesale, by the pallet or in full truckloads? Send us your required dimensions, quantities and delivery destination for a tailored quotation.

Email: info@intergard.eu
Telephone: +31 546 579030

Order your hardwood decking joists online or contact Intergard for competitive wholesale prices.