Category: Advice

What is Volumetric Concrete and how does it work?

Volumetric concrete is a mobile batching plant that allows on-site mixing of concrete. Unlike traditional ready-mix concrete, where the concrete is pre-mixed and transported to the construction site, volumetric concrete mixers carry the raw materials separately and mix them on-site as needed.

The process involves a volumetric mixer, which is essentially a mobile concrete batching plant mounted on a truck or trailer. The mixer has separate compartments for sand, cement, water and aggregates. These components are precisely measured and mixed on-site based on the specific requirements of the project. This on-demand mixing capability provides a level of flexibility and efficiency that traditional concrete delivery methods struggle to match.

Benefits of Volumetric Concrete

Efficiency

As volumetric trucks are able to mix the exact quantities of concrete, your risk of ordering too little or too much concrete for a project is significantly reduced, which offers a huge advantage over other forms of ready mix concrete, both in terms of cost risk and concrete waste disposal.  

For example, if too much concrete has been ordered the material can remain on the lorry and be used for another job, as the components of the concrete (sand, aggregate, cement and water) have not been mixed together, and you will only be charged for the material used.  

On the flipside, if more concrete is required than has been ordered, providing there is sufficient spare material on the truck, additional concrete can be mixed to complete your pour, avoid the need to order in additional trucks and possibly having to bring labour back to site another day.

Flexibility and Customisation

Volumetric concrete allows for real-time adjustments to the concrete mix, enabling construction professionals to tailor the material to the specific needs of each project. This flexibility is particularly valuable when dealing with varying project specifications and requirements.

Reduced Waste

Traditional ready-mix concrete often results in leftover material that goes unused, leading to waste. With volumetric concrete, the mix is created on-site, eliminating the risk of overordering and reducing waste. This aligns with the growing emphasis on sustainability in the construction industry.

Time Savings

Volumetric concrete can significantly reduce construction time by eliminating delays caused by waiting for concrete deliveries. Construction teams can have a continuous and controlled supply of fresh concrete, enhancing project timelines.

Quality Control

On-site mixing allows for better control over the quality of the concrete. Construction professionals can make adjustments as needed, ensuring that the final product meets the desired strength and durability standards.

When is it best to use Volumetric Concrete?

Remote or Challenging Sites

Volumetric concrete is particularly valuable in remote or challenging construction sites. The ability to be able to batch on site enables the lorries to travel longer distances and remain on site for longer periods of time as the concrete is batched on demand, rather than being transported to site ready mixed, where there is a risk of the concrete curing in the truck overtime.  Working in conjunction with a concrete line pump it is possible to deliver Volumetric concrete to pretty much anywhere it is needed.

Road Construction

Road projects, such as repairs and maintenance, benefit from the versatility of volumetric concrete. Construction teams can produce concrete on-site, responding promptly to changing conditions and ensuring a continuous supply.

Small to Medium-Scale Projects

Volumetric concrete is ideal for small to medium-scale construction projects where precise quantities of concrete are needed. Its flexibility and cost-effectiveness make it a preferred choice for residential and commercial developments.

Infrastructure Development

Major infrastructure projects, including bridges and tunnels, can capitalise on the advantages of volumetric concrete. The ability to adjust the mix on-site ensures that the concrete meets the specific requirements of these critical structures.

Volumetric concrete is reshaping the construction industry by offering a dynamic and efficient alternative to traditional concrete delivery methods. Its flexibility, reduced waste, and on-demand mixing capabilities make it a valuable choice for a wide range of construction projects.

The concrete mix for farm and agricultural sites needs to be particularly durable, especially for external areas and routes between units. This is due to higher levels of wear and tear from farm equipment scraping surfaces, in addition to variable weather conditions and temperatures throughout the year. 

The same goes for livestock feeding / housing areas, where the integrity of concrete for hygiene purposes and ease of cleaning is of utmost importance. This is in order to comply with Quality Assurance Schemes and the Food Safety Act. These areas need to withstand high levels of animal traffic, mud and a mixture of wet and dry conditions, with minimal / no degradation in surface quality. 

Types of concrete needed for agricultural purposes

Below we have set out the options for concrete choices for agricultural sites. The key here is to consider whether your site has ‘high’, or ‘severe’ exposure to the elements. RC35 is a great option for high exposure sites, but if severe exposure is likely, you may wish to consider RC40 concrete. 

Both are appropriate for stable floors, livestock areas and agricultural paving. 

Light storage and livestock areas

RC35 concrete / PAV2

We recommend RC35 concrete, which is a heavy duty concrete for use with embedded reinforcement. It offers a durable, high quality finish, similar to RC30, but is much more substantial making it suitable for commercial and industrial use. 

Common applications include piling and external slabbing and paving that will be subject to the constant loading and scraping imposed by industrial vehicles and machinery.

What is PAV2?

PAV2 mixes have an air entrainment additive, to create standard sized air bubbles in concrete. This helps to protect the surface from freeze-thaw cycles, making it especially useful for outdoor paving.

Benefits of RC35 concrete for agricultural purposes: 

• High durability and finish to withstand heavy machinery and traffic
• Non-slip finish for safe handling of equipment and livestock
• Supports compliance with Quality Assurance Schemes
• Provides a barrier between ground moisture and stored materials / machinery 

Other options for agricultural yards and external areas

For external paving / routes between different units on farms, while you can use C35, C40 is also a viable option as mentioned for ‘severe’ exposure areas (those that won’t have protection from elements at all, or on sites where conditions are extreme all year round). 

Similarly to RC35 concrete, RC40 has the same uses – stable floors, high traffic agricultural paving and roads – to provide a tough, durable barrier against regular scraping from machinery and between ground floor moisture and materials / livestock feed / equipment. 

Benefits of RC40 concrete for agricultural purposes: 

• Best for ‘severe’ exposure sites
• High durability and finish to withstand heavy machinery and traffic
• Non-slip finish for safe handling of equipment and livestock
• Supports compliance with Quality Assurance Schemes
• Provides a barrier between ground moisture and stored materials / machinery 

Working out how much concrete is needed for agricultural and farming sites

Estimating concrete quantities can be a tricky and often unnecessarily expensive task due to inadvertent over ordering. 

Use our concrete calculator to work out how much you think you will need and we will arrive on-site and mix the exact requirements for the job.

For sites that are difficult to access, such as facilities narrow access entrances, and for large concrete pours where the use of wheel barrows will be very time consuming, we would recommend using one of our concrete pumps, which will pump the concrete from the concrete lorry to the pour-site area saving you on time, labour and hard work! Call us for a quote on 01273 594394, or fill in our handy contact form. 

What are building foundations and why are they so important?

Building foundations – while not visible and below ground level – are one of the most crucial aspects of any build. They are used to ensure a building’s weight is distributed in an even fashion and to facilitate a solid footing for the building as a whole. Getting the footings and foundations right is paramount to avoid costly remedies later down the line, or, in worse case scenarios, even having to knock the building down and start again!

We’re here to guide you on the type of concrete and foundation needed to ensure your project is completed without a hitch. You should also work closely with a structural engineer and building control to ensure any footings you have plans for are appropriate for the building type / improvements you are planning.

Things to consider when laying foundations

Trees and soil:

Ordinarily carried out by digging a series of holes (trial holes) across your site, you can then use the analysis of soil type to judge general conditions for the location as a whole. It’s important to know the type of soil where you’re building, as certain soil makeups can cause subsidence and these need to be negated by building the correct footings and foundations.

Even trees have a role to play in your decision making. In simple terms, depending on various factors, the closer a tree is to a new building the deeper the foundations must be taken down. To give an example – poplar trees have a high water demand and can potentially cause serious problems to foundations in shrinkable clays and soils, which may lead to cracking and sometimes movement. Also, should you have an existing tree in your garden, having it felled will not mean that the foundations will not be affected – heave in clay soil can take place when it takes up moisture and swells after the felling or removal of trees and hedgerows. In these instances, your structural engineer will advise what is necessary to overcome these issues and, in extreme cases, it may be necessary to use a different type of foundation, such as piled or raft foundation.

Drainage and nearby structures:

Drainage issues close to foundations can be very expensive to rectify. The proximity to your project can make excavation works more difficult, even impacting the structural integrity of your foundations.

It may sound obvious, however the simplest way to negate problems with drainage pipes is to reroute the trenches that house the drainage a greater distance away from your foundations, if practical.

The important aspect to remember – if drainage is close to your foundations – is to make sure no further loads from your foundations are put on the trenches for the drains. You can avoid this by simply increasing your foundation depth

Types of foundations

You get shallow or deep foundations, mainly. Commercial projects often require deep foundations, to allow a greater depth of soil to support taller and larger structures.

Domestic projects on the other hand – for example for a new build home or extension – will only require shallower foundations, generally with less depth than the width of the property.

Types of shallow foundations:

Isolated footings / Pad foundation

These are designed to support an individual column and are either square, circular or rectangular. Created to carry concentrated loads, with the thickness worked out by assessing the weight of the load and surrounding ground conditions.

Combined footing

When two or more columns are too close together, such that if you used isolated footings they’d overlap, then combined footings are the solution. Rectangular in shape, the extra length allows more than one column to sit atop.

Strip foundation

These are used to support continuous or sometimes stepped above ground structures, such as a wall, or multiple closely spaced columns. A good example of when these are used is for house foundations or footings for conservatories and extensions.

Raft or mat foundation

This type of foundation will need careful design by a structural engineer to ensure it’s suitable for your project. It’s designed as a solution if you can’t use strip foundations for any reason.

Essentially, a raft solution gets its name because it’s a concrete slab that sits under the entire extension and ‘floats’ on the ground like a raft on water.

Types of deep foundations (most often more commercial projects):

Caisson – also known as pier / drilled shaft foundations

These are cast on site, where a column of the required depth is drilled into the ground, then the hole has reinforced steel lowered into it, which is then filled with concrete.

Pile foundations

When the ground close to the surface isn’t appropriate for heavy loads, piles are put into the ground and filled with concrete. A ground beam then is used to enable the surface to be built upon.

How to create your concrete footings and foundations

Before you start any project, it’s vital that you seek expert advice on the type of foundations you will need, from a structural engineer. You will also need planning permission for any major project involving the need for new foundations, and your project will need to be signed off by Building Regulations.

Once you’ve sought the appropriate advice, you are ready to do the following:

Get your ground ready, cleared and dug to the right depth

Mark out the area where your concrete is going to be poured, using string and pegs, allow an additional 50-75mm if you are planning to use formwork (which is what holds your concrete in place while it is curing).

Once ready, dig your foundations to the specified depth. If you have sufficient space at your property, this is much easier if you use a digger to do so Depending on the ground conditions, the stability of the side walls of the trenches may not be great and there could be a risk of the side falling in, particularly if heavy rain is forecast, so it’s important to get your Building Inspector lined up and concrete booking scheduled in advance, to avoid any such issues.

Once you’ve dug your foundations, You’ll also want to clear the ground of any stones / rocks / tree roots etc. and then level and compact the area. For floor slabs and isolated footings, you’ll want to leave enough depth for sub base (i.e. hardcore laid over the top of soil (approx. 100mm – subject to ground conditions), damp proof membrane (DPM), then the concrete itself.

Add your sub base and make it compact the ground again

Add your sub base and compact the ground, then add your Damp Proof Membrane (DPM) and set up your formwork for your concrete. Use our handy guide on laying concrete to guide you through this process.

Order and pour your concrete!

If you’ve followed the above steps, then you’re all set to order and pour your concrete. However, don’t forget to book your concrete well in advance to avoid any delays on site, you can always make a provisional booking and if necessary move your pour to another day if you have problems on site.

Our ready mix concrete lorries will deliver the exact amount you need to site and our concrete pumps will pump the concrete from the lorry directly into your foundation excavation. Simply get in touch and we’ll help you work out what you need to successfully complete your project.

It is essential that your building is positioned on a flat, solid and stable base, in order to bear the substantial weight and allow doors and windows to hang correctly and open smoothly.

The base should always be the same size as the footprint of the building, making a base larger than your building is not recommended, this increases the risk of water ingress.

Type of concrete needed

C20/Gen 3 or C25 are the most suitable types of ready mixed concrete for sheds, log cabins and garden offices. Higher strength concrete and reinforcement may be required for larger structures and therefore mix strengths should always be checked with your builder or building supplier.

How to measure a concrete base

1. Location – Consider shade vs natural light. For a potting shed, you’ll want a shaded area, whereas a greenhouse obviously needs natural light and sunshine. Take time to consider proximity to mains for power supply, or the need to get a qualified electrician to install and RCD (Residual Current Device) from the main panel box. Leave a one-metre gap between your shed and any surrounding walls or fencing, being careful of overhanging branches.

2. Measure your base – accurately measure and mark out the dimensions of your base. Check your dimensions are even by measuring diagonally; if they are the same, then the sides are equal.

3. Level the site – either dig down to firm subsoil or put a layer of hardcore down and leave enough depth for the concrete to go on top.. About half of the depth of your base should be above ground level.

4. Create a timber frame to contain the concrete. Use a spirit level to check the frame sits level on top of the hardcore and make any necessary adjustments. Place wooden pegs inside the frame and regular intervals to hold it in place. Sit pegs below the top level of the frame to make it easy to level off the concrete.

How much concrete needed for a base

Estimating concrete quantities can be a difficult, frustrating and often expensive task. You can use our concrete calculator to calculate how much you think you will need and we will arrive on-site and mix the exact requirements for the job.

For bases that are difficult to access, such as at the bottom of your garden and for large concrete pours where the use of wheel barrows will be very time consuming, we would recommend using one of our concrete pumps, which will pump the concrete from the concrete lorry to the pour area saving you on time, labour and hard work! Call us for a quote

1. Preparing the garage base

To prevent your garage floor concrete slab from cracking, it’s important to have a solid and level base. Additionally, if the ground level is to be built up, then proper compaction must be ensured to avoid uneven settlement.

Make sure you remove all plant matter, rocks and debris and compact the area before adding the hardcore sub base and compacting again. You should have a solid compacted hardcore base on the soil, on which the reinforcement can be placed. The depths of hardcore will vary depending on ground conditions so we would recommend checking with your architect or builder.

Then lay a Damp Proof Membrane (DPM) – ensuring the edges are turned up to form a tray and any joints are overlapped and taped.

Create a timber frame to contain the concrete. Use a spirit level to check the frame sits level on top of the hardcore and make any necessary adjustments. Place wooden pegs inside the frame at regular intervals to hold it in place. Sit pegs below the top level of the frame to make it easy to level off the concrete.

Overall the base should be 175mm bigger than the building on all sides.

2. Measuring the thickness of the garage floor slab

The thickness of the garage floor slab depends on factors such as:

• Types of loads placed on the slab
• Climatic condition
• Mix of the concrete
• Span of the concrete

Standard thickness of the garage floor slabs used worldwide is 150mm. Depending upon the load placed on the slab, the thickness should be adjusted. Typical examples are:

1. Light Loads – For one to two light cars, the concrete should be at least 100mm thick
2. Medium Loads – If the garage is used for average-sized vehicles and/or medium to heavy trucks, the concrete needs to be 150mm thick
3. Heavy Loads – If your garage floor is going to see constant traffic from heavy vehicles, it is recommended the concrete is 150mm to 200mm thick. The floor must also be treated and sealed properly to avoid heavy loads, like large trucks, cracking the concrete

3. Reinforcement

The reinforcement steel should be used just to hold the slab in position and avoid cracks. The slab will be supported by the ground underneath.

4. Placing of Concrete

Before placing the concrete make sure you have all the necessary tools and labour available to help. Having enough labour is often over looked and you can run the risk of the concrete going off before you have had chance to level it off and finish with a trowel.

Typical basic tools required:

• Shovel
• Rake
• Timber tamp (i.e. length of 4×2” timber)
• Hand trowels
• Spirit level or laser level

When placing the concrete work in 1-2m strips across the width of the slab, levelling with a tamp and finishing with trowels as you go. A shovel and rake will be needed to help move the concrete around.  A vibrating poker can be used to help level and compact the concrete.

The edges of the base should be chamfered to allow any water to drain off.

For bases that are difficult to access, such as at the bottom of your garden and for large concrete pours where the use of wheel barrows will be very time consuming, we would recommend using one of our concrete pumps, which will pump the concrete directly from the concrete lorry to the pour area saving you on time, labour and hard work! Call us for a quote

5. Curing of Garage Floor Slab

Use slab curing methods, such as a water cure. Concrete is flooded; ponded, or a mist sprayer is used, to ensure proper curing of the garage floor slab and to help prevent shrinkage cracks

It is important to allow sufficient curing time before applying any finishes to your garage floor as moisture on the slab may cause the finishes to lift or debond.

6. Finishing for Garage Floor

You can finish the garage floor using:

• Garage Floor Epoxy
• Garage Floor Paint
• Garage Floor Mats
• Garage Floor Tiles
• Polished Concrete Flooring.

How much concrete is needed for a base?

Estimating concrete quantities can be a difficult, frustrating and often expensive task. You can use our concrete calculator to calculate how much you think you will need and we will arrive on-site and mix the exact requirements for the job.

What you need to know

Extra care must be taken when pouring concrete in cold weather. The biggest problem you will face is if concrete is allowed to cool below freezing point, the concrete may become so damaged that it will be unfit for purpose. 

It is also important to understand that even if temperatures do not drop below 0°C, the concrete will develop strength at a much slower rate than during warmer weather.

The main problem when pouring at sub zero is if freshly poured concrete cools below 0°C the water in the mix will freeze and expand resulting in damaged and unusable concrete.

The key to a successful pour is for the concrete first to be able to reach a strength of about 2 N/mm2, if this happens it is much more likely to resist any problematic expansion. In most occasions and for most mixes, this strength is achieved within 48 hours if the concrete is kept at or above 5°C. However, even after the concrete has reached 2 N/mm2 low temperatures will slow down the strength development.

During cold weather the most important thing is to keep the concrete warm (above 5°C) for the first 48 hours, then it is important to ensure that the strength is still allowed to develop, at the lower rate associated with cold weather.

Checklist for pouring on cold weather

• Plan ahead: Check the temperature the day before and on the day of your pour
• If temperatures are likely to be below 5°C then make a plan to avoid complications
• Never allow concrete to be laid onto frozen ground, ice or snow!
• Use thermal blankets to help prevent frost from forming overnight and help to retain the heat of the concrete
• Protect freshly laid concrete with thermal blankets and windbreaks (if necessary)
• Don’t let your concrete freeze within 48 hours of being poured

If you need any further advice regarding the placement of concrete during cold weather conditions please do not hesitate to contact our office on 01273 594394