How much does excavation work cost?

Significant Factors in Your Excavation Cost

There are all sorts of reasons you might need to excavate earth, and the costs will depend on the below factors:

The size of the excavation, and what sort of foundations you need to lay.

Below you can see average costs laid out for different size projects and based on alternative foundation types.

Contractors may quote in different ways – for example, they might provide an ‘all-in’ price for a total job, a charge per day, per cubic metre, or per acre. It is, therefore, essential you calculate the complete excavation requirements before comparing quotes.

The deeper the excavation works and the larger the overall project, the higher its cost.

Purpose of your excavation and the site layout.

Another key cost factor is the exact layout of the excavation, with a simple hole being a straightforward project. However, you may need to have steps built to access sloped sites or batons erected to support the sides of the excavation and prevent slippage.

We’ve looked above at comparable costs for two typical foundation types, but these can vary depending on the nature of the project.

For example, digging excavations for the same seven by ten-metre building with one internal cross wall would cost approximately £4,200 for deep strip foundations, £6,400 for trench fill foundations and £11,500 for trench fill foundations at two metres deep.

Excavation process and soil type.

Finally, the type of soil and the excavation method will impact the overall costs. Machinery could include grab lorries, diggers or hand excavations – all dependent on the volume of the excavation and access to your property.

You’d be looking at around £160 per person per day for manual excavation works, plus the cost of a grab lorry to remove the waste and potentially skip hire for land clearance waste. The more tonnes of soil you need to be removed, the cheaper the cost per tonne but the higher the total budget.

Soil types will also be a factor, with sandy soils taking longer to excavate and needing more reinforcements during the work to ensure the sides of the excavation remain stable.

Additional Charges in Excavation Works

One of the most considerable costs in excavations that sometimes isn’t budgeted for relates to the piping and drains underneath the property.

You may need to consider:

• A CCTV Drain Survey to inspect the location and conditions of drainage systems underneath the excavation site to identify whether they need to be moved.
• Drain Repair callouts to fix any problems caused by the excavation – which can be costly, so is best avoided by relocating mains pipes before the work starts.
• Plumber Callout charges if you need to reposition any outside taps or repair any water supply pipes running into your property.

Other cost considerations include:

• Landscaping or laying turf to repair the soil around the excavation site – the average cost of patching up a lawn is £14 per square metre.
• Access requirements include clearing a side return, removing fences, or building a new pathway to allow access to the excavation area and subsequent construction work.
• Replacing or repairing tarmacking impacted by the excavation – an average cost of £2,000 depending on the size of the area.
• Dropping the curb outside your home, essential if you are building an extension for a garage space.

Breaking Down an Excavation Cost Quote

Quotes for an excavation project will generally be given as a total price, provided you have supplied the contractor with the exact specification and size of the excavation area.

Generally, contractors will split the total cost into:

• Materials (including equipment hire) – 55%
• Labour – 30%
• Waste removal – 15%

There are multiple possible elements to an excavation project, so it’s advisable to ask for an itemised quote to know exactly what is included.

Elements include waste removal, preparatory groundwork, site inspections, vehicle hire, skip hire, reinforcing batons and repair works to the property.

Which Projects or Home Improvements Require Excavation Work?

All of the above factors will determine your excavation cost – but will you need to hire a professional for your project?

The majority of jobs that require excavations will benefit from an experienced contractor. They will provide services such as equipment, waste haulage and labour included in the price and can complete an excavation much faster than digging by hand.

Typical projects where excavations are required include:

• Building an extension to the side or rear of your property.
• Installing a swimming pool.
• Building a rock wall as a perimeter or decorative feature.
• Converting a basement or building a new one.
• Laying the foundations for a new garage or brick outbuilding.

If you’re unsure whether you need excavation works, it’s best to consult a contractor before budgeting.

FAQs - Budgeting for Excavation Works

Let’s run through some of the most popular questions regarding the costs of excavation work!

How Much Earth Can Be Excavated Per Day?

The exact volume depends on the type of soil and what equipment you have. Manually excavating can take substantially longer than using a commercial machine, hence the cost-effectiveness of using a professional contractor.

With a 40 HP JCB and excavating standard soil types, you might expect to remove up to 30 or 40 cubic metres per hour. Higher spec machinery can increase the excavation speed by around 20% per day.

Do I Need Planning Permission for Excavation Work?

You might do, yes. If you are creating an excavation to build a new property or construction or extend into a basement, you will likely need permission. This also applies to any works that will alter the property’s external appearance, such as adding a light well.

Excavations close to a neighbouring property may also require a party wall agreement.

What Happens if There are Mains Pipes Where I Need to Excavate?

A land survey is essential to identify whether piping, such as sewage pipes or drainage, sits underneath the excavation area. Breaking or damaging mains power lines can be extremely costly.

The best course of action is to look at having these pipes moved or rerouted to allow the excavation to take place safely.

Can I Excavate Land at Any Time of Year?

Most contractors will prefer to carry out excavation work during the dryer summer months. This avoids problems with rainwater flooding the excavation site – which can cause contamination, slippages and safety hazards.

Extensive excavations can be pumped out to ensure water doesn’t cause a problem and delay progress, although working in dryer periods will avoid many potential issues.

How Long Do Excavation Works Normally Take?

Your project’s duration will very much depend on the size of the required excavation, what equipment is being used, and the type of soil on your property.

General jobs to excavate land for a construction project take between two and four weeks, including preparation works, site clearance, and concrete pouring.

References:

• https://www.homebuilding.co.uk/advice/foundations-cost-guide
• https://www.planningportal.co.uk/info/200130/common_projects/5/basements#:~:text=Excavating%20to%20create%20a%20new,likely%20to%20require%20planning%20permission.
• https://www.homeadvisor.com/cost/landscape/excavate-land/