Complete UK 2026 specification guide forC8/10 concreteblinding layers, GEN 1 ordering notes, volume, thickness, cost, mix selection and BS EN 206 / BS 8500 context.
What Is C8/10 Concrete in the UK?
C8/10 concreteis a low-strength concrete grade used where the project needs a clean, stable, level and economical working layer rather than a high-load structural element. In UK concrete notation, the first number refers to characteristic cylinder strength and the second refers to characteristic cube strength at 28 days. For C8/10, this means an approximate strength class of 8 N/mm² cylinder strength and 10 N/mm² cube strength under standard test conditions.
On real UK sites, C8/10 is most commonly discussed as ablinding concrete,lean concrete, or sometimes a general-purpose low-strength mix similar toGEN 1. Supplier naming can vary, so the safest way to order is to describe both the application and the required performance: “C8/10 concrete for a 50mm blinding layer below foundations” is clearer than simply asking for “weak concrete” or “foundation blinding”. For technical background, see The Concrete Centre’s explanation ofBS 8500 and BS EN 206 standards.
2026 Practical Summary
C8/10 is best treated as anon-structural or very lightly loaded concrete. It is ideal for blinding layers, levelling rough excavations, separating reinforcement from soil, protecting membranes, kerb backing, trench fill and general groundworks. It should not replace an engineer-specified structural grade such as C20/25, C25/30 or C30/37.
Blinding Layer
Creates a clean working surface over excavated ground so reinforcement, membranes and shuttering are easier to position accurately.
Low Cement / Lean Mix
Designed for economy and workability rather than high compressive strength, making it cheaper than structural concrete grades.
Not Structural
Do not use C8/10 for reinforced slabs, driveways, beams, columns or foundations unless a competent designer has specifically approved it.
C8/10 Concrete Specification — UK 2026 Quick Reference
The table below summarises the most important C8/10 specification points for UK domestic and light commercial groundworks. Exact mix details should be confirmed with the ready-mix supplier, because BS EN 206 and BS 8500 allow concrete to be specified by designed, designated, standardised prescribed, prescribed or proprietary routes depending on the project.
- Specification Item: Strength class; Typical C8/10 Blinding Detail: C8/10; Practical Note: Approx. 8 N/mm² cylinder and 10 N/mm² cube at 28 days; Status: Low strength
- Specification Item: Common designation; Typical C8/10 Blinding Detail: Often ordered as GEN 1 / low-strength general concrete; Practical Note: Confirm exact designation with the supplier; Status: Common
- Specification Item: Blinding thickness; Typical C8/10 Blinding Detail: 25–75mm typical; 50mm common; Practical Note: Increase if excavation is uneven or soft spots need levelling; Status: Practical
- Specification Item: Consistence; Typical C8/10 Blinding Detail: S2–S3 common; S4 if pump-friendly workability is needed; Practical Note: Do not add water on site without supplier approval; Status: Specify
- Specification Item: Aggregate size; Typical C8/10 Blinding Detail: 10mm or 20mm depending on thickness and placement; Practical Note: Thin blinding may benefit from smaller aggregate; Status: Check
- Specification Item: Structural suitability; Typical C8/10 Blinding Detail: Not normally structural; Practical Note: Use engineer-specified grade for load-bearing concrete; Status: Limited
Important Specification Warning
C8/10 is not a shortcut for structural concrete. If the concrete will support structural loads, contain reinforcement, form a driveway, act as a suspended slab, or be exposed to aggressive ground, frost, salts or heavy abrasion, check the correct BS 8500 specification with an engineer, Building Control or the ready-mix technical team.
Where C8/10 Concrete Is Used — Blinding, Fill & Groundworks
The best way to understand C8/10 is to think of it as asite preparation concrete. It is poured before the main structural concrete or around lightly loaded features so the next trade has a cleaner and more predictable surface. In many cases the blinding is not there to carry the building; it is there to make the main concrete, reinforcement and waterproofing easier to install correctly.
1. Foundation Blinding Below Footings
After foundation trenches are excavated, the bottom may be muddy, uneven or contaminated with loose soil. A thin C8/10 blinding layer seals the formation, reduces contamination from subsoil and gives steel fixers or groundworkers a better surface to work on. It can also make it easier to maintain cover to reinforcement and avoid concrete loss into open-textured ground.
2. Slab Blinding Below DPM or Insulation
For ground-bearing slabs, a blinding layer can create a smoother base for a damp proof membrane, insulation boards or gas membrane. A rough hardcore surface can puncture membranes; a thin blinding layer reduces that risk. Where radon, methane or waterproofing systems are involved, always follow the membrane manufacturer’s installation detail rather than assuming ordinary blinding is enough.
3. Kerb Backing, Haunching and Bedding
Low-strength concrete is commonly used behind kerbs, edgings and channels where the concrete provides support but is not a high-grade structural element. In areas with vehicle impact, heavy traffic or highways specification requirements, use the project specification rather than a generic C8/10 assumption.
4. Trench Fill and Mass Fill
C8/10 may be suitable for filling voids, adjusting excavation levels or bringing trench bottoms up to the required level before stronger concrete is placed. It is economical because it avoids using expensive structural mixes where high performance is unnecessary. However, if the trench is part of a structural foundation design, the grade should match the designer’s requirement.
5. Non-Structural Domestic Groundworks
Garden features, minor levelling, pipe bedding protection and temporary working areas may use C8/10 or similar low-strength mixes. The key word isnon-structural. If vehicles, retaining loads, reinforcement, frost-salt exposure or permanent building loads are involved, move up to the correct grade.
Good Use
50mm blinding beneath a foundation or slab where the main structural concrete is placed above later.
Borderline Use
Unreinforced fill in mild ground conditions — acceptable only if the design does not require structural performance.
Poor Use
Driveway, reinforced slab, suspended floor, retaining wall, beam, column or chemically aggressive ground.
How to Work out C8/10 Blinding Concrete Volume
For most blinding layers, the working is simple: multiply the area by the blinding thickness. The only tricky part is making sure your thickness is entered in metres. A 50mm layer is 0.05m. A 75mm layer is 0.075m. A 100mm layer is 0.10m.
Blinding Volume Formula
Concrete volume (m³) = Area (m²) × Thickness (m). Add 5–10% for waste, small level differences, spillage and uneven excavation.
- Area: 10 m²; 25mm Layer: 0.25 m³; 50mm Layer: 0.50 m³; 75mm Layer: 0.75 m³; 100mm Layer: 1.00 m³
- Area: 25 m²; 25mm Layer: 0.63 m³; 50mm Layer: 1.25 m³; 75mm Layer: 1.88 m³; 100mm Layer: 2.50 m³
- Area: 50 m²; 25mm Layer: 1.25 m³; 50mm Layer: 2.50 m³; 75mm Layer: 3.75 m³; 100mm Layer: 5.00 m³
- Area: 75 m²; 25mm Layer: 1.88 m³; 50mm Layer: 3.75 m³; 75mm Layer: 5.63 m³; 100mm Layer: 7.50 m³
- Area: 100 m²; 25mm Layer: 2.50 m³; 50mm Layer: 5.00 m³; 75mm Layer: 7.50 m³; 100mm Layer: 10.00 m³
- Area: 150 m²; 25mm Layer: 3.75 m³; 50mm Layer: 7.50 m³; 75mm Layer: 11.25 m³; 100mm Layer: 15.00 m³
For small domestic jobs, the supplier’s minimum order can matter more than the exact determined amount. Many ready-mix deliveries have a minimum load or a short-load charge. If your blinding working is under 1m³, bagged concrete, volumetric concrete or combining the order with another pour may be more economical. Use ourConcrete Volume Guidefor full slab, footing and trench shapes.
C8/10 Concrete Cost in 2026 — UK Budget Guidance
C8/10 is normally cheaper than structural ready-mix because it has lower strength requirements and is often used for simple placement. However, the delivered cost is still affected by region, delivery distance, minimum order size, pump hire, waiting time, Saturday delivery and whether the supplier batches it as a standard designated mix or a custom low-strength mix.
As a practical 2026 budgeting range, many UK projects should allow roughly£90–£125 per m³for low-strength ready-mix before pump hire and abnormal delivery charges. London, the South East and difficult-access sites can exceed this. Small orders can appear expensive on a per-m³ basis because the lorry, driver, batching time and delivery slot are similar whether you order 1.5 m³ or 6 m³.
- Cost Item: C8/10 ready-mix; Typical 2026 Allowance: £90–£125/m³; When It Applies: General low-strength delivery; Budget Impact: Core cost
- Cost Item: Short-load charge; Typical 2026 Allowance: £40–£100+; When It Applies: Small orders below supplier minimum; Budget Impact: Common
- Cost Item: Line pump; Typical 2026 Allowance: £275–£500+; When It Applies: No direct truck access; Budget Impact: Major add-on
- Cost Item: Waiting time; Typical 2026 Allowance: Charged after free unload window; When It Applies: Slow barrowing or late site readiness; Budget Impact: Avoidable
- Cost Item: Cold weather protection; Typical 2026 Allowance: Blankets / insulation / delay; When It Applies: Frost risk or near-freezing temperatures; Budget Impact: Seasonal
Do Not Choose C8/10 Just to Save Money
Using C8/10 where a structural grade is required can create expensive remedial work. Saving £15–£35/m³ on the concrete is not worth the risk if the element should have been C20/25, C25/30, C30/37 or a durability-designed BS 8500 mix.
BS EN 206 & BS 8500 Context for C8/10 Concrete
UK concrete specification is based aroundBS EN 206and the complementary British StandardBS 8500. BS EN 206 sets out the common framework for concrete specification, production and conformity, while BS 8500 provides UK-specific guidance, national provisions and practical specification routes. The 2023 revision of BS 8500 also expanded the range of lower-carbon concretes that can be specified in the UK.
For a simple blinding layer, the project may not require the same level of design measurement as a reinforced retaining wall or structural slab. Even so, the same specification discipline still matters: strength class, intended use, exposure, consistence, maximum aggregate size, delivery method and any site restrictions should be clear before the order is placed. See BSI’sBS 8500 method of specifying concreteoverview for the standard’s scope.
What “C8/10” Means
- Cindicates normal or heavyweight concrete strength class terminology.
- 8refers to characteristic cylinder compressive strength in N/mm².
- 10refers to characteristic cube compressive strength in N/mm².
- The strength is normally assessed at 28 days under standard test conditions.
- The grade alone does not define every requirement — exposure, consistence and material details still matter.
When Exposure Class Still Matters
Blinding often sits in a low-risk context, but not always. Ground conditions, sulfates, permanent saturation, frost action, chemical contamination or de-icing salts can change the concrete requirement. If the blinding is only a temporary working surface beneath a separately specified structural element, the requirements may be simple. If it becomes part of a permanent ground-bearing system, ask for proper specification advice. For durability selection, use ourExposure Class Guide UK.
BS EN 206
Provides the general European concrete framework for specification, production and conformity.
BS 8500
Adds UK-specific provisions, specification routes, durability guidance and national experience.
2026 Low-Carbon Focus
Modern specifications increasingly consider cement type, additions and embodied carbon, even for routine concrete orders.
How to Order C8/10 Blinding Concrete from a Supplier
Ordering C8/10 concrete is straightforward if you give the supplier the information they need. The biggest mistakes are ordering by nickname only, underestimating volume, assuming the lorry can reach the pour, or failing to plan follow-on work. Ready-mix concrete is time-sensitive; once the truck arrives, the site must be ready.
Use This Supplier Script
Example Order Wording
“I need approximately 3.0 m³ of C8/10 concrete for a 50mm blinding layer below foundations. It is non-structural blinding over prepared ground. Please quote for delivery to [postcode], S3 consistence unless you recommend otherwise, 20mm aggregate unless 10mm is better for the thin layer, and confirm any short-load, waiting-time or pump charges.”
Information to Confirm Before Delivery
- Exact volume:Work out net volume and add 5–10% allowance for uneven excavation.
- Access:Check whether the mixer can reverse close enough or whether a pump, dumper or barrow route is needed.
- Discharge time:Have labour and resources ready before the truck arrives.
- Ground condition:Remove standing water, loose soil, ice, frost and organic material.
- Weather:Protect against rain washout, rapid drying and frost.
- Documentation:Ask whether a delivery ticket and conformity details are supplied.
- Follow-on timing:Do not place membranes, insulation or reinforcement until the surface is suitable.
Ready-Mix vs Site-Mixed C8/10
For very small blinding patches, site mixing may be acceptable if the work is non-critical. For larger areas, ready-mix is faster and more consistent. A blinding layer is thin, so delays during hand mixing can leave cold joints, uneven thickness and poor level control. Ready-mix also gives a clearer delivery record, which is useful where the project needs quality documentation.
C8/10 Blinding Layer Installation Checklist
The quality of a blinding layer depends more on preparation than strength. Even a low-strength concrete needs a stable base, sensible curing and clean placement. Poor blinding can crack, break up, debond, create high spots, trap water or leave an uneven surface for reinforcement and membranes.
Step 1 — Prepare the Formation
Trim the excavation to the correct level and remove loose soil, roots, organic material and standing water. If the ground is soft, pumping or unstable, a blinding layer alone will not fix the problem. Seek groundworks or engineering advice before pouring.
Step 2 — Set Level Pins or Guides
Because blinding is thin, a few millimetres of error can make a noticeable difference. Use level pegs, laser level marks or temporary screed guides so the placed concrete remains close to the specified thickness. This is particularly important below insulation or membranes.
Step 3 — Place and Level Quickly
C8/10 does not need a decorative finish, but it should be level enough for the next stage. Spread with rakes and shovels, then tamp or screed lightly. Avoid excessive water addition; wetting the mix on site can reduce surface stability and create segregation.
Step 4 — Protect the Surface
Protect the blinding from heavy rain, frost and rapid drying. In hot or windy weather, stop the surface drying too quickly. In cold weather, never pour onto frozen ground and protect fresh concrete if temperatures may fall close to freezing. For winter planning, see ourFrost Protection Cold Weather Concreting Guide.
Step 5 — Inspect Before Follow-On Work
Before installing a DPM, gas membrane, waterproofing layer or reinforcement, check for high spots, sharp stones, cracks, contamination and standing water. A blinding layer should make the next stage easier, not hide problems below the permanent construction.
C8/10 vs Other UK Concrete Grades
C8/10 sits at the low-strength end of the normal practical grade range. It is useful because it is economical, but it is not a general replacement for stronger grades. The table below gives a practical comparison for common domestic and commercial decisions.
- Grade: C8/10; Common Context: GEN 1 / low-strength; Typical Use: Blinding, fill, kerb backing; Use Instead of C8/10 When…: Non-structural only
- Grade: C12/15; Common Context: General mass fill; Typical Use: Light groundworks, bedding, paths; Use Instead of C8/10 When…: More strength is needed but still light-duty
- Grade: C16/20; Common Context: Light domestic; Typical Use: Some foundations, floors, paths; Use Instead of C8/10 When…: Element carries more load than blinding
- Grade: C20/25; Common Context: Standard domestic structural; Typical Use: Foundations, slabs, footings; Use Instead of C8/10 When…: Building Control or engineer specifies structural use
- Grade: C25/30; Common Context: Driveways / structural slabs; Typical Use: Vehicle slabs, reinforced floors; Use Instead of C8/10 When…: Traffic, reinforcement or durability is important
- Grade: C30/37+; Common Context: Commercial / engineered; Typical Use: Beams, columns, heavy slabs; Use Instead of C8/10 When…: Designed structural performance is required
For a full grade-by-grade breakdown, use ourConcrete Grades Comparison UKandC8/10 to C40/50 Mix Design Guide.
Quality Checks, Site Mistakes & Practical Acceptance
A C8/10 blinding layer is low strength, but it still needs basic quality control. The aim is not to achieve a power-floated finish or structural load capacity; the aim is to provide a clean, stable and reasonably level working surface. A poor blinding layer can cause problems later because reinforcement chairs rock, membranes puncture, insulation boards bridge over high spots, or the structural concrete thickness becomes inconsistent.
What Good C8/10 Blinding Looks Like
- Even coverage:The blinding should cover the full excavation footprint without thin bare patches or exposed hardcore.
- Reasonable level:It should follow the required formation levels and not create high spots that reduce structural concrete depth.
- Clean surface:Loose mud, debris, standing water and broken laitance should be removed before membranes or reinforcement are installed.
- Stable enough for follow-on trades:Operatives should be able to work on it without the surface breaking up excessively.
- Protected early age:The surface should not be damaged by frost, heavy rain, drying winds or premature traffic.
Common Mistakes to Avoid
The most common mistake is ordering too little concrete because the working assumes a perfectly flat excavation. Real excavations are rarely perfect. Clay, chalk, made ground, compacted hardcore and hand-dug trenches all create small level variations. A 50mm blinding layer over uneven ground can easily consume more concrete than the neat drawing suggests. A 10% allowance is usually sensible, and more may be needed where trenches are rough or over-dug.
Another mistake is treating blinding as a way to hide bad ground. Blinding can tidy a surface, but it cannot make soft ground suitable, remove water pressure, fix contamination or replace proper sub-base preparation. If the excavation pumps water, moves underfoot or contains unsuitable material, deal with the ground condition first.
Do not make the mix wetter on site just to make it flow. Adding water after batching can reduce strength, increase segregation and leave a weak dusty surface. If the site needs easier placement, ask the supplier for the right consistence or admixture before the load is dispatched.
Red Flag
If the drawing, engineer or Building Control note specifies a structural concrete grade, exposure class, minimum cement content or designed mix, do not substitute C8/10 unless the specifier approves it in writing. Blinding is usually separate from the structural concrete above it.
Low-Carbon and Sustainability Notes for C8/10 Blinding in 2026
UK concrete specification in 2026 is increasingly focused on carbon reduction, material efficiency and avoiding unnecessary over-specification. C8/10 blinding is already a relatively low-strength use, so the biggest sustainability gains usually come from ordering the correct volume, avoiding waste, choosing the right thickness and not using a high-strength structural mix where a low-strength working layer is sufficient.
BS 8500 updates have increased attention on lower-carbon concretes and the use of cement combinations where appropriate. For blinding, ask whether the supplier can provide a lower-carbon option that still meets the required strength class, setting time and site programme. This may include suitable cement additions or recycled aggregate options depending on local plant capability and project requirements.
Practical Ways to Reduce Waste
- Measure before ordering:Recheck trench widths, overbreak and actual excavation levels on the day before the pour.
- Plan leftover use:Prepare small pads, post bases or kerb backing areas if a small surplus is expected.
- Avoid over-thick blinding:Increasing from 50mm to 75mm raises volume by 50%, so only increase thickness when site conditions justify it.
- Coordinate deliveries:Combining blinding with other non-structural fill work can reduce small-load surcharges and wasted haulage.
- Use local suppliers:Shorter delivery distances can reduce transport cost, waiting time and disruption.
Do not reduce concrete grade, cement content or thickness below the project requirement just for carbon savings. Sustainable construction means using the right concrete in the right place: enough performance for durability and safety, without unnecessary over-specification.
Always Match the Grade to the Job — Not Just the Price
C8/10 is an efficient blinding and low-strength fill grade, but it is not a universal concrete. Confirm the correct strength class, exposure condition, consistence and aggregate size before ordering, especially if the concrete forms part of permanent structural work.
C8/10 Concrete Grade FAQs — UK 2026
Common questions about C8/10 concrete, GEN 1 concrete, blinding layers and UK ordering practice.
Related Concrete Guides & UK Guides
Continue planning your concrete project with these practical UK construction resources.
For related concrete mix design and proportion working, see MixDesignCalc.xyz.