Cumaru – 90 x 19mm – Smooth/Reeded – Hidden-fixing edge groove
Product Code: D-000827£48.40 per m² ex. vat
Lengths available:
- 1820mm
- 2140mm
- 2440mm
- 2740mm
- 3050mm
- 3350mm
- 3660mm
- 3960mm
- 4270mm
- 4570mm
- 4880mm
- 5180mm
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Price (Based on 2140mm)
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– Yellow Cumaru decking board
– Dimension: 90 x 19mm
– Surface texture: Smooth/Reeded
– Features hidden-fixing edge groove
– Extremely dense & durable hardwood
– Naturally resistant to insect and fungal attack
– Eased edges for a smooth finish
– Recommended to install with a decking wrench for straightening bent boards
– Hire service available for decking wrench
– Ideal for outdoor decking projects due to its durability and resistance properties
Cumaru is renowned for its outstanding colouration. Whilst boards tend to range from light brown through to dark honey, sparks of orange and dark golden brown can also feature.
One of our greatest strengths is our well-organized delivery system. Whether we use external couriers or our own fleet of vehicles, we ensure your decking arrives promptly and in excellent condition. Delivery charges are calculated based on your postcode, the distance to your location, and the length and weight of the materials. For more details, please see our Delivery Terms & Conditions.
Overview: Choosing the Right Installation Method
Hardwood decking offers exceptional durability and natural beauty for premium outdoor living spaces. The installation method depends on your aesthetic preference—face screwing for maximum strength or hidden fastening for a seamless finish. Careful attention to installation details is essential to ensure optimal long-term performance and weather resistance.
Preparation and Acclimatisation
Before installation, allow the hardwood boards to acclimatise on-site for at least 48 hours. Store them flat, off the ground, and protected from direct sunlight and moisture. Ensure the sub-frame is constructed from pressure-treated softwood joists with adequate ventilation beneath the deck to prevent moisture accumulation. Please note: We do not supply softwood sub-frame materials – source from your local timber merchant.
Fixing Methods
Face Screwing (Traditional Method)
The traditional method offering maximum strength and reliability for hardwood decking. Always pilot drill before fitting screws to prevent splitting and drill holes 2mm oversize to allow for natural expansion and contraction. Use corrosion-resistant stainless steel screws suitable for hardwood. Each screw hole can be plugged with matching hardwood plugs for improved aesthetics. Countersink screws slightly below the surface when plugging.
Hidden Fastening
The Deckwise hidden fastening system provides a premium, screw-free surface finish with professional results. Each clip screws securely into your sub-frame and slots into the edge-grooved board, automatically maintaining consistent spacing. Pre-grooved boards are available, or groove on-site using a biscuit jointer. Please note: We do not recommend hidden fastening systems for oak decking installations due to the species’ movement characteristics.
Installing Face Screwed Hardwood Decking
Face screwing provides maximum strength and reliability:
- Always pilot drill before fitting screws to prevent splitting
- Drill holes 2mm oversize to allow for natural expansion and contraction
- Maintain minimum 4mm gap between boards for standard widths
- Use 5–6mm gap for wider boards (145mm+)
- Use corrosion-resistant stainless steel screws suitable for hardwood
- Countersink screws slightly below the surface when plugging
- Each screw hole can be plugged with matching hardwood plugs for improved aesthetics
Installing Hidden Fastening System
For a premium, screw-free surface finish:
- Boards must be edge-grooved to accept hidden fastening clips
- Each clip screws securely into the sub-frame and slots into the board edge
- Automatically maintains consistent 4mm board spacing
- Pre-grooved boards available, or groove on-site using a biscuit jointer
- Creates a clean, uninterrupted deck surface with no visible fixings
- Important: Not recommended for oak decking due to the species’ movement characteristics
Board Spacing and Movement
Proper spacing accommodates the natural movement of hardwood:
- Minimum 4mm gap between boards for standard widths
- 5–6mm gap recommended for wider boards (145mm+)
- Hardwood may expand or contract slightly with seasonal climate changes, though movement is typically minimal
Ventilation and Sub-Frame Requirements
All hardwood decking installations require proper support and airflow:
- Maintain 400mm centre-to-centre joist spacing throughout
- Use pressure-treated softwood joists for your sub-frame
- Ensure adequate cross-ventilation beneath the deck to prevent moisture accumulation
Professional Installation Tools
We strongly recommend using a hardwood decking wrench during installation. This specialized self-locking deck board straightening tool allows you to hold warped or bent boards perfectly straight while fasteners are installed, ensuring professional results and a uniform finish across your entire deck.
Need Help?
While professional installation is advised for best results, we’re here to support DIYers with installation advice and technical guidance. Contact us for tailored support to suit your project.
Overview: Tropical Hardwood Care and Maintenance
Tropical hardwoods including Balau, Ipe, Cumaru, and Angelim Pedra are renowned for extreme density and natural resistance to rot and insects. With proper care, these premium timbers can last 25 to 75+ years. This guide provides essential maintenance practices to preserve the beauty and performance of your installation.
Your Timber Species
- Ipe (Brazilian Walnut): Olive-brown to dark-brown | 40-75+ years
- Cumaru (Brazilian Teak): Reddish-brown to cherry red | 30-50+ years
- Balau (Red/Brown Balau): Consistent brown tones | 20-30+ years
- Angelim Pedra (Brazilian Ironwood): Beige-brown with red undertones | 25+ years
Natural Weathering
- Without treatment, all species weather from rich brown to silvery-grey over 6-18 months
- UV rays and moisture cause superficial colour change only
- Weathering doesn’t affect durability or structural integrity
- Original colour can be restored with cleaning, sanding, and oiling
Colour Preservation Options
Choose your maintenance approach early:
Option 1: Natural Silver-Grey (Low Maintenance)
- Apply initial UV-protective oil after installation
- Allow natural weathering to silver-grey
- Simply keep clean with regular sweeping
- Minimal ongoing effort required
Option 2: Maintain Brown Colour (Higher Maintenance)
- Apply UV-resistant oil annually (spring/autumn optimal)
- High-sun areas may need reapplication every 6-9 months
- Products: Penofin Hardwood Formula or Messmer’s UV Plus
- Maintains vibrant colour and grain patterns
Initial Treatment After Installation
End Grain Sealing
- Seal any cut ends immediately to prevent splitting
UV Protection
- Apply UV-protective penetrating oil within first few weeks
- Use products designed for tropical hardwoods (Penofin, Messmer’s, Ipe Oil)
- Skip only if choosing natural silvering option
Cleaning and Maintenance Schedule
Weekly Tasks
- Sweep with soft brush to remove debris
- Remove leaves, twigs, and organic matter promptly
- Clean between boards to prevent moisture buildup
- Spot clean spills immediately with mild soap and water
Seasonal Deep Cleaning (Spring and Autumn)
- Remove all debris thoroughly
- Use commercial hardwood cleaners (Woodrich EFC-38 or Messmer’s)
- Two-part cleaner/brightener systems restore grey wood to near-original colour
- Allow 1-2 days drying before applying treatments
- Apply UV-protective oil if maintaining brown colour
- Inspect and tighten fasteners
- Check for damaged boards
- Verify proper drainage and ventilation
Additional Summer Tasks
- Monitor for excessive drying
- Maintain regular sweeping routine
Additional Winter Tasks
- Remove snow/ice promptly (avoid metal shovels)
- Monitor for standing water or ice buildup
Annual Inspection
- Check all fasteners and tighten as needed
- Inspect for loose, warped, or damaged boards
- Ensure water drains away properly
- Verify ventilation pathways remain clear
- Trim back vegetation for clearance and airflow
- Address any issues immediately
Common Problems and Solutions
- Surface Greying: Clean, lightly sand, apply UV-protective oil
- Mould/Mildew: Clean with hardwood cleaner, improve ventilation and drainage
- Cupping/Movement: Ensure proper ventilation beneath structure, keep debris clear
- Persistent Staining: Use specialized hardwood stain removers, light sanding if needed
Cleaning Methods
Basic Cleaning
- Use mild soap and water with soft brush
- Stiff brush for stubborn dirt
- Rinse thoroughly with garden hose
- Clean spills promptly to prevent staining
Pressure Washing (Use with Caution)
- Only when necessary for deep cleaning
- Start at 3.5 MPa, maximum 8.3 MPa for Ipe (less for Balau)
- Fan spray tip with 40-60 degree spread
- Work with grain about 30cm from surface
- Test inconspicuous area first
- Improper technique permanently damages wood
Stain Removal
- Most household stains fade naturally over time
- Use specialized hardwood cleaners for stubborn stains
- Light sanding may be needed for deep stains
- Reapply protective oil after treatment
Oil Application Process
Follow these steps for best results:
- Clean surface thoroughly with wood cleaner/brightener
- Allow to dry completely (1-2 days)
- Lightly sand with 80-grit sandpaper if needed
- Remove all dust and debris
- Apply oil according to manufacturer’s instructions
- Work in manageable sections to avoid lap marks
- Reapply when water no longer beads on surface
Ventilation and Drainage
Essential for preventing moisture damage:
- Keep vegetation trimmed back from all surfaces
- Ensure water drains away from structure
- Never allow standing water on deck
- Maintain clear ventilation pathways beneath structure
- Remove any obstructions under deck
- Good airflow prevents cupping and movement
Restoration and Refinishing
When to Refinish
- Wood looks dry or faded
- Water no longer beads on oiled surfaces
- After several years if colour restoration desired
Restoration Process
- Strip old finishes if necessary (use wood stripper)
- Clean with wood brightener
- Light sand with 80-grit sandpaper to remove silvered surface
- Remove all dust thoroughly
- Apply fresh oil finish
- Restored areas will weather to match surroundings
Product Recommendations
Cleaners
- Speak with our team about the Treatex products best suited for your selected tropical hardwood species
UV-Protective Oils
- Speak with our team about the Treatex products best suited for your selected tropical hardwood species
Tools
- Soft-bristled brush/broom
- Stiff scrubbing brush
- 80-grit sandpaper
- Garden hose with spray nozzle
Best Practices for Long-Term Care
- Establish regular maintenance routine from the start
- Keep detailed records of treatments and dates
- Use only products specifically designed for tropical hardwoods
- Choose maintenance approach early (natural grey vs. maintained colour)
- Apply treatments in dry, temperate conditions
- Never allow standing water to persist
- Address small issues immediately before they escalate
- Sand lightly when restoration needed
- Reapply oil when water stops beading
- Consider professional cleaning every 3-5 years for large installations
- Consistent care dramatically extends lifespan to maximum potential
Need Help?
Your tropical hardwood is a premium investment designed to last decades. With proper care, Balau, Ipe, Cumaru, and Angelim Pedra installations remain beautiful and functional for 25-75+ years. For product recommendations, maintenance advice, or specific care questions, our experienced team is always on hand to assist. Contact us for tailored guidance to suit your project.
