The best sand for block paving joints is kiln-dried jointing sand or polymeric sand. These options lock blocks in place, resist weeds, and last longer than standard building sand. Kiln-dried sand costs around £4-6 per 25kg bag and works for most driveways. Polymeric sand costs £8-12 per bag but offers superior weed resistance.
Block paving looks brilliant when new. Six months later, weeds push through gaps and sand washes away. The right jointing sand prevents this headache and keeps your driveway looking smart for years.
What Makes Good Block Paving Sand
Good jointing sand needs specific qualities that standard building sand lacks.
Grain size matters most. The sand must flow easily between narrow joints but stay put once installed. Fine sand (0.1-0.3mm) works best for tight joints. Medium sand (0.3-0.6mm) suits wider gaps.
Angular particles grip better than rounded grains. Sharp edges lock together and resist movement when vehicles drive over them.
Low moisture content prevents problems. Wet sand clumps and won’t flow properly. It also promotes weed growth and can stain light-coloured blocks.
Clean sand lasts longer. Impurities like clay or organic matter feed weeds and create weak spots that wash out easily.
Types of Sand for Block Paving Joints
Kiln-Dried Jointing Sand
Kiln-dried sand is heated to remove all moisture and contaminants. This creates free-flowing sand that fills joints completely.
Benefits:
- Flows easily into tight spaces
- Won’t stain blocks during installation
- Resists initial weed growth
- Costs less than alternatives
- Available everywhere
Drawbacks:
- Needs regular topping up
- Limited long-term weed resistance
- Can wash out in heavy rain
Best for: Budget-conscious projects, areas with light foot traffic, DIY installations.
Popular brands include Marshalls Weatherpoint and Hanson Kiln Dried Sand.
Polymeric Sand
Polymeric sand contains binding agents that activate with water. Once wet and dried, it forms a semi-solid joint that flexes with movement.
Benefits:
- Excellent weed resistance
- Stays put in heavy rain
- Self-healing properties
- Reduces maintenance
- Insect resistant
Drawbacks:
- Costs more initially
- Tricky installation process
- Can haze light blocks if misapplied
- Limited colour options
Best for: High-traffic areas, premium installations, areas prone to weeds.
Leading brands include Techniseal and Azpects Easy Joint.
Sharp Sand
Regular sharp sand is the budget option but comes with significant limitations.
Benefits:
- Very cheap (£2-3 per 25kg)
- Readily available
- Easy to work with
Drawbacks:
- Washes out quickly
- No weed resistance
- Needs frequent replacement
- Can contain impurities
Best for: Temporary installations or very tight budgets only.
Resin-Bound Jointing Compounds
These premium products mix resin with fine aggregates to create virtually permanent joints.
Benefits:
- Exceptional durability
- Complete weed prevention
- Various colours available
- Professional appearance
Drawbacks:
- Expensive (£15-25 per bag)
- Requires perfect application
- Difficult to repair
- Professional installation recommended
Best for: Commercial projects, high-end residential work.
Choosing the Right Sand for Your Project
Consider Your Block Type
Concrete blocks work with any jointing sand type. The uniform shape creates consistent joint widths that suit standard products.
Clay pavers often have irregular edges that create varying joint widths. Polymeric sand handles this variation better than kiln-dried options.
Natural stone needs careful sand selection. Light-coloured stones can stain easily, so choose neutral-coloured sands and avoid clay-based products.
Assess Your Environment
High rainfall areas need sand that won’t wash away. Polymeric sand or resin-bound compounds work best in wet climates.
Shaded locations encourage moss and algae growth. Choose sands with anti-microbial properties or plan for regular cleaning.
Heavy traffic zones require robust jointing. Polymeric sand handles vehicle loads better than kiln-dried alternatives.
Coastal locations face salt spray and strong winds. Marine-resistant polymeric sands cope with these harsh conditions.
Budget Considerations
| Sand Type | Cost per 25kg | Coverage | Annual Maintenance |
|---|---|---|---|
| Sharp Sand | £2-3 | 15-20m² | High |
| Kiln-Dried | £4-6 | 12-15m² | Medium |
| Polymeric | £8-12 | 10-12m² | Low |
| Resin-Bound | £15-25 | 8-10m² | Minimal |
Calculate total cost over five years, including labour for re-pointing. Polymeric sand often costs less long-term despite higher initial expense.
Installation Guide
Preparing the Surface
Clean joints thoroughly before adding new sand. Remove all old sand, weeds, and debris using a pressure washer or stiff brush.
Check block levels. Uneven blocks create drainage problems and joint failures. Re-lay any sunken or raised blocks before proceeding.
Ensure proper drainage. Water must drain away from the surface. Poor drainage causes sand loss and block movement.
Application Process
1. Choose the right weather. Install sand during dry conditions with no rain forecast for 24 hours. Avoid windy days that scatter fine sand.
2. Pour sand gradually. Don’t dump entire bags at once. Work in manageable sections to maintain control.
3. Sweep thoroughly. Use a soft brush to work sand into joints. Push sand down firmly but don’t compact excessively.
4. Remove excess sand. Clean all sand from block surfaces before it sets. Dried sand can permanently stain some materials.
5. Activate polymeric sand. Mist lightly with water if using polymeric products. Follow manufacturer instructions exactly.
Common Installation Mistakes
Overfilling joints creates weak spots that crack under pressure. Fill joints to 3mm below the surface.
Insufficient compaction leaves gaps where weeds can establish. Ensure sand reaches the bottom of joints.
Poor surface cleaning leaves residue that stains blocks. Always remove excess sand immediately.
Wrong weather conditions ruin polymeric sand installations. Never work in rain or extreme heat.
Maintenance and Longevity
Regular Inspection
Check joints every six months for signs of loss or weed growth. Early intervention prevents major problems.
Look for:
- Low sand levels exposing block edges
- Weed seedlings in joints
- Cracks or soft spots in polymeric joints
- Staining on block surfaces
Topping Up Joints
Kiln-dried sand needs annual topping up in most situations. High-traffic areas may need attention twice yearly.
Polymeric sand typically lasts 3-5 years before requiring renewal. Quality installation extends this lifespan significantly.
Weed Control
Even the best sands can’t prevent all weeds. Regular maintenance keeps problems manageable.
Prevention beats cure. Spray joints with preventative weed killer in early spring before growth begins.
Spot treatment handles individual weeds quickly. Remove by hand or use targeted herbicide application.
Full renovation becomes necessary when weed problems overwhelm the joints. This means removing all sand and starting fresh.
Regional Considerations in the UK
Northern England and Scotland
Harsh winters and frequent freeze-thaw cycles demand robust jointing sand. Polymeric sand handles temperature changes better than basic alternatives.
Consider: Extra drainage provisions for snow melt and longer periods of standing water.
Southern England
Milder conditions allow more sand options but summer heat can stress some polymeric products.
Consider: UV-resistant formulations for areas with high sun exposure.
Coastal Areas
Salt air and strong winds create challenging conditions for all jointing materials.
Consider: Marine-grade polymeric sands designed for coastal installations.
Urban vs Rural
City locations face different challenges than countryside installations.
Urban considerations:
- Air pollution affects sand longevity
- Limited access for maintenance
- Higher traffic loads
Rural considerations:
- Organic debris accumulation
- Wildlife damage
- Seasonal access issues
Cost Analysis and Value
Initial Investment Comparison
A typical 50m² driveway needs:
- Sharp sand: £8-12 initially, £40-60 over 5 years
- Kiln-dried sand: £15-25 initially, £50-75 over 5 years
- Polymeric sand: £35-50 initially, £45-65 over 5 years
- Resin-bound: £75-125 initially, £80-130 over 5 years
Hidden Costs
Factor in labour costs for maintenance. Professional re-pointing costs £8-15 per square metre.
DIY maintenance saves money but requires time and effort. Budget for tools, additional sand, and cleaning materials.
Professional maintenance costs more but ensures proper installation and longevity.
Long-Term Value
Quality jointing sand protects your entire investment. Poor joints cause:
- Block movement and cracking
- Weed damage to sub-base
- Water penetration problems
- Reduced property value
Troubleshooting Common Problems
Sand Keeps Washing Away
Cause: Usually poor drainage or wrong sand type for conditions.
Solution: Improve drainage first, then switch to polymeric sand or resin-bound compound.
Weeds Growing Through Joints
Cause: Sand allows light and moisture to reach weed seeds.
Solution: Remove weeds completely, treat with herbicide, then use polymeric sand with weed-resistant properties.
Joints Cracking or Soft
Cause: Water damage to polymeric sand or poor initial installation.
Solution: Remove affected sand completely and reinstall following manufacturer guidelines exactly.
Block Edges Chipping
Cause: Insufficient joint sand allows blocks to move against each other.
Solution: Ensure joints are properly filled and compacted. Consider upgrading to stronger jointing material.
Professional vs DIY Installation
When to DIY
Suitable projects:
- Small areas under 30m²
- Straight, simple layouts
- Using kiln-dried sand
- Good weather conditions
Required skills:
- Ability to work methodically
- Understanding of basic drainage
- Physical capability for manual work
When to Use Professionals
Complex situations:
- Large areas over 100m²
- Polymeric or resin-bound installation
- Existing drainage problems
- Historical or listed properties
Professional benefits:
- Guarantee on workmanship
- Proper equipment and techniques
- Insurance coverage
- Time savings
Environmental Impact
Sustainable Options
Recycled materials in some jointing sands reduce environmental impact without compromising performance.
Local sourcing cuts transport emissions. Many UK suppliers offer regionally-sourced materials.
Permeable systems allow rainwater to drain naturally rather than overwhelming sewers.
Disposal Considerations
Old sand removal creates waste that needs proper disposal. Some materials can be recycled as sub-base for other projects.
Chemical-free options break down naturally and don’t harm soil or waterways when replaced.
Expert Tips and Best Practices
Professional Secrets
Test a small area first when trying new products. This reveals any compatibility issues before committing to the full project.
Work in sections rather than attempting the entire area at once. This maintains quality and allows for adjustments.
Keep detailed records of products used, installation dates, and maintenance activities. This information helps with warranty claims and future planning.
Timing Considerations
Spring installation allows full settling before winter stress. Avoid installation during flowering season if allergic to pollen.
Autumn installation works well but leaves less time for settling. Ensure completion well before first frost.
Summer installation suits polymeric products but requires careful moisture management.
Quality Indicators
Consistent colour throughout the bag indicates quality control during manufacturing.
Free-flowing texture without clumps shows proper moisture content and storage.
Clear labelling with coverage rates and installation instructions suggests reputable manufacturers.
Frequently Asked Questions
How much sand do I need for my block paving?
Calculate 1kg of sand per square metre for standard joints (3-5mm wide). A 25kg bag typically covers 12-20m² depending on joint width and block thickness.
Can I mix different types of jointing sand?
Never mix different sand types. Each has specific properties that don’t combine well. Mixing creates weak spots and reduces overall performance.
How long does polymeric sand take to set?
Initial setting takes 24-48 hours in dry conditions. Full curing requires 7-14 days. Avoid heavy traffic during this period.
What happens if it rains during installation?
Light rain during kiln-dried sand installation isn’t critical. Heavy rain or any moisture during polymeric sand installation ruins the product. Wait for completely dry conditions.
How do I remove old polymeric sand?
Use a pressure washer with narrow nozzle or mechanical joint removal tools. Chemical softeners help with stubborn sections. Complete removal is essential before applying new sand.
Why do my block edges keep chipping?
Insufficient joint sand allows blocks to knock against each other. Ensure joints are properly filled and consider switching to a more robust sand type.
Can I use building sand for block paving joints?
Building sand lacks the specific properties needed for jointing. It retains moisture, encourages weeds, and washes out easily. Always use purpose-made jointing sand.
How often should I top up joints?
Kiln-dried sand needs annual attention in most situations. Polymeric sand lasts 3-5 years with proper installation. High-traffic areas need more frequent maintenance.
Conclusion
The best sand for block paving joints depends on your specific situation, budget, and maintenance preferences. Kiln-dried jointing sand offers excellent value for most UK driveways and provides reliable performance with annual maintenance. Polymeric sand costs more initially but reduces long-term maintenance and offers superior weed resistance.
For budget-conscious projects with light traffic, quality kiln-dried sand from reputable suppliers like Wickes or Travis Perkins delivers solid results. High-traffic areas and premium installations benefit from polymeric sand’s enhanced durability and low maintenance requirements.
Remember that proper installation matters more than sand type. Clean preparation, correct application techniques, and suitable weather conditions determine long-term success regardless of which product you choose.
Key takeaways:
- Match sand type to your specific conditions and budget
- Prioritise proper installation over premium products
- Plan maintenance from day one
- Consider professional installation for complex projects
- Factor long-term costs into your decision
The right jointing sand protects your entire block paving investment. Choose wisely, install carefully, and maintain regularly for decades of trouble-free performance.