Borehole
Drilling
Vertical boreholes for ground source heat pump systems, drilled by our own team to depths of up to 180 metres. Closed loop, open loop, and simultaneous casing for difficult ground — all handled in-house.
Borehole
Drilling
Vertical boreholes for ground source heat pump systems, drilled by our own team to depths of up to 180 metres. Closed loop, open loop, and simultaneous casing for difficult ground — all handled in-house.
What Is a Borehole?
A borehole is a narrow hole — typically 115–150mm in diameter — drilled vertically deep into the earth. For ground source heat pump systems, boreholes house vertical ground loop collectors that circulate a fluid to absorb the stable thermal energy stored in the ground.
The ground maintains a near-constant temperature of 10–12°C year-round below a depth of around 15 metres, making it an exceptionally reliable heat source regardless of weather or season.
The depth and number of boreholes required depends on the building's total heat demand and the thermal conductivity of the local geology. Boreholes are the preferred collector option for properties with limited garden space, requiring only a small surface footprint.
What Is a Borehole?
A borehole is a narrow hole — typically 115–150mm in diameter — drilled vertically deep into the earth. For ground source heat pump systems, boreholes house vertical ground loop collectors that circulate a fluid to absorb the stable thermal energy stored in the ground.
The ground maintains a near-constant temperature of 10–12°C year-round below a depth of around 15 metres, making it an exceptionally reliable heat source regardless of weather or season.
The depth and number of boreholes required depends on the building's total heat demand and the thermal conductivity of the local geology. Boreholes are the preferred collector option for properties with limited garden space, requiring only a small surface footprint.
What to Expect on Drilling Day
The complete process from arrival to completion
Planning & Preparation
Confirm whether planning consent is needed — most residential projects are covered by permitted development. Restrictions may apply in Conservation Areas, SSSIs or National Parks. Clear vehicle access to the drilling location is essential.
Rig Arrival & Setup
Our crew arrives with the drilling rig on a transporter, plus a compressor (4×4m, 3.5 tonnes), trailer, fuel bowser and grouting machine. The rig runs on rubber tracks and weighs 8 tonnes — it may mark soft surfaces, especially in wet conditions. All equipment is positioned as close together as possible.
Drilling Begins
The drill cuts through soil and soft materials into the rock below. Metal casing is inserted to prevent collapse — 15m is included as standard. We use air, air/mist, water or drilling mud methods depending on geology. For poor ground conditions, we offer simultaneous drilling and casing to a maximum of 150m. Borehole sizes are 115mm upwards.
Water & Spoil Management
Water is almost always encountered at depth and must be treated as foul water. We channel it to a soakaway, divert it to a foul drain or, in extreme cases, contain and remove it. Drilling produces ~1.5 tonnes of rock and soil spoil per 100m depth. Unless otherwise agreed, spoil disposal is the customer's responsibility.
Loop Installation & Grouting
Geothermal loops (PE100 pipe, 32–40mm diameter) are inserted into the completed boreholes — single or double-loop configurations. Every loop is flow and pressure-tested, then sealed with a Thermal Bentonite Grout combined with Silica Sands. The grout is mixed on site and pumped from the bottom to the top of the borehole, filling all air gaps to maximise heat transfer and prevent ground contamination.
Connection & Completion
Your ground worker excavates around each borehole (1–1.2m deep × 1m wide) so we can cut the casing below ground and fusion weld header pipes. These are laid in trenches to the manifold, tested, then backfilled — leaving no visible evidence. The manifold connects all boreholes to one point with header pipework running to the plant room. We supply trench drawings and require two access points (500mm apart) with sweeping bends into the plant room.
What to Expect on Drilling Day
The complete process from arrival to completion
Planning & Preparation
Confirm whether planning consent is needed — most residential projects are covered by permitted development. Restrictions may apply in Conservation Areas, SSSIs or National Parks. Clear vehicle access to the drilling location is essential.
Rig Arrival & Setup
Our crew arrives with the drilling rig on a transporter, plus a compressor (4×4m, 3.5 tonnes), trailer, fuel bowser and grouting machine. The rig runs on rubber tracks and weighs 8 tonnes — it may mark soft surfaces, especially in wet conditions. All equipment is positioned as close together as possible.
Drilling Begins
The drill cuts through soil and soft materials into the rock below. Metal casing is inserted to prevent collapse — 15m is included as standard. We use air, air/mist, water or drilling mud methods depending on geology. For poor ground conditions, we offer simultaneous drilling and casing to a maximum of 150m. Borehole sizes are 115mm upwards.
Water & Spoil Management
Water is almost always encountered at depth and must be treated as foul water. We channel it to a soakaway, divert it to a foul drain or, in extreme cases, contain and remove it. Drilling produces ~1.5 tonnes of rock and soil spoil per 100m depth. Unless otherwise agreed, spoil disposal is the customer's responsibility.
Loop Installation & Grouting
Geothermal loops (PE100 pipe, 32–40mm diameter) are inserted into the completed boreholes — single or double-loop configurations. Every loop is flow and pressure-tested, then sealed with a Thermal Bentonite Grout combined with Silica Sands. The grout is mixed on site and pumped from the bottom to the top of the borehole, filling all air gaps to maximise heat transfer and prevent ground contamination.
Connection & Completion
Your ground worker excavates around each borehole (1–1.2m deep × 1m wide) so we can cut the casing below ground and fusion weld header pipes. These are laid in trenches to the manifold, tested, then backfilled — leaving no visible evidence. The manifold connects all boreholes to one point with header pipework running to the plant room. We supply trench drawings and require two access points (500mm apart) with sweeping bends into the plant room.
Our Drilling Capabilities
A fully equipped in-house operation for all borehole types
Our Drilling Capabilities
A fully equipped in-house operation for all borehole types
Good to Know Before We Arrive
Important practical information for a smooth drilling project
💧 Water Is Inevitable
At 100m depth, water is almost always encountered. It must be treated as foul water. We manage it via soakaways, foul drains or containment. Additional disposal costs, if any, are detailed on your estimate.
🪨 Spoil & Sand
Expect ~1.5 tonnes of broken rock per 100m. Unless otherwise agreed, disposal is the customer's responsibility. Surplus grouting sand can be used to bed pipework and protect against sharp rocks after backfill.
🚛 Equipment Footprint
The rig (8 tonnes, rubber tracks), compressor (4×4m, 3.5 tonnes), trailer, fuel bowser and grouting machine all need space. Soft surfaces may show marks — especially in wet weather. All kit must be positioned close together.
📋 Planning Permission
Most residential borehole drilling is permitted development under the Town and Country Planning Act. Restrictions may apply in Conservation Areas, SSSIs and National Parks — always check with your local authority beforehand.
🏗️ Your Ground Worker's Role
All digging, backfill and materials are the ground worker's responsibility. We supply trench drawings and specs. Two plant room access points (500mm apart) with sweeping bends are needed. Your builder provides these and handles remedial works.
🔗 After Drilling: The Manifold
The manifold connects all boreholes to one point, then runs header pipework to the heat pump. It has a plastic manhole cover and is best placed in a soft landscape area where it can be concealed with planters, shrubs or garden furniture.
Good to Know Before We Arrive
Important practical information for a smooth drilling project
💧 Water Is Inevitable
At 100m depth, water is almost always encountered. It must be treated as foul water. We manage it via soakaways, foul drains or containment. Additional disposal costs, if any, are detailed on your estimate.
🪨 Spoil & Sand
Expect ~1.5 tonnes of broken rock per 100m. Unless otherwise agreed, disposal is the customer's responsibility. Surplus grouting sand can be used to bed pipework and protect against sharp rocks after backfill.
🚛 Equipment Footprint
The rig (8 tonnes, rubber tracks), compressor (4×4m, 3.5 tonnes), trailer, fuel bowser and grouting machine all need space. Soft surfaces may show marks — especially in wet weather. All kit must be positioned close together.
📋 Planning Permission
Most residential borehole drilling is permitted development under the Town and Country Planning Act. Restrictions may apply in Conservation Areas, SSSIs and National Parks — always check with your local authority beforehand.
🏗️ Your Ground Worker's Role
All digging, backfill and materials are the ground worker's responsibility. We supply trench drawings and specs. Two plant room access points (500mm apart) with sweeping bends are needed. Your builder provides these and handles remedial works.
🔗 After Drilling: The Manifold
The manifold connects all boreholes to one point, then runs header pipework to the heat pump. It has a plastic manhole cover and is best placed in a soft landscape area where it can be concealed with planters, shrubs or garden furniture.
Frequently Asked Questions
Common questions about borehole drilling for heat pumps
Most domestic boreholes are around 100 metres deep, though this varies depending on the building's heat demand and the thermal conductivity of the local geology. We can drill to a maximum depth of 180 metres. A typical 100m borehole takes approximately one day to complete.
The number depends on the building's total heat demand and domestic hot water requirements. A typical 3–4 bedroom home usually needs 2 to 3 boreholes. Larger properties or commercial buildings may require more. This is determined during the system design stage.
In most cases, no. Residential borehole drilling typically falls under permitted development rights of the Town and Country Planning Act. However, local restrictions may apply if the site is in a Conservation Area, a Site of Special Scientific Interest (SSSI) or a National Park. We always recommend confirming with your local planning authority before works begin.
A closed loop system circulates antifreeze fluid through sealed PE100 pipes inserted into the borehole — the fluid absorbs ground heat and returns to the heat pump. An open loop system draws groundwater directly from an aquifer, passes it through the heat pump, and discharges it. Closed loop is far more common for residential installations as it doesn't require a suitable aquifer or an Environment Agency abstraction licence.
The drilling rig weighs 8 tonnes and runs on rubber tracks, so it may leave marks on soft ground — especially grass in wet conditions. The compressor and support equipment also need space. However, once drilling is complete and trenches are backfilled, there is no visible evidence of the boreholes above ground. The manifold can be concealed beneath landscaping or garden furniture.
Once the geothermal loops are inserted, we pump a mixture of Thermal Bentonite Grout and Silica Sands into the borehole from bottom to top using our specialised grout mixer. This fills all air gaps between the loops and the borehole walls, ensuring maximum thermal contact and preventing contamination of local water sources. The grout composition is adjusted based on geological conditions.
We are equipped for all ground conditions. We use multiple drilling methods including air, air/mist, water and drilling muds. For particularly poor or unstable ground, we offer simultaneous drilling and casing methods to stabilise the borehole as it is drilled, to a maximum finished depth of 150 metres. 15m of metal casing through soft surface material is included as standard in our pricing.
Borehole drilling is an industrial process and does generate noise — the rig and compressor are the main sources. Noise levels are comparable to other construction activities. We work during standard hours and can discuss scheduling with you or your neighbours if noise sensitivity is a concern. Drilling a typical 100m borehole takes around one day.
Frequently Asked Questions
Common questions about borehole drilling for heat pumps
Most domestic boreholes are around 100 metres deep, though this varies depending on the building's heat demand and the thermal conductivity of the local geology. We can drill to a maximum depth of 180 metres. A typical 100m borehole takes approximately one day to complete.
The number depends on the building's total heat demand and domestic hot water requirements. A typical 3–4 bedroom home usually needs 2 to 3 boreholes. Larger properties or commercial buildings may require more. This is determined during the system design stage.
In most cases, no. Residential borehole drilling typically falls under permitted development rights of the Town and Country Planning Act. However, local restrictions may apply if the site is in a Conservation Area, a Site of Special Scientific Interest (SSSI) or a National Park. We always recommend confirming with your local planning authority before works begin.
A closed loop system circulates antifreeze fluid through sealed PE100 pipes inserted into the borehole — the fluid absorbs ground heat and returns to the heat pump. An open loop system draws groundwater directly from an aquifer, passes it through the heat pump, and discharges it. Closed loop is far more common for residential installations as it doesn't require a suitable aquifer or an Environment Agency abstraction licence.
The drilling rig weighs 8 tonnes and runs on rubber tracks, so it may leave marks on soft ground — especially grass in wet conditions. The compressor and support equipment also need space. However, once drilling is complete and trenches are backfilled, there is no visible evidence of the boreholes above ground. The manifold can be concealed beneath landscaping or garden furniture.
Once the geothermal loops are inserted, we pump a mixture of Thermal Bentonite Grout and Silica Sands into the borehole from bottom to top using our specialised grout mixer. This fills all air gaps between the loops and the borehole walls, ensuring maximum thermal contact and preventing contamination of local water sources. The grout composition is adjusted based on geological conditions.
We are equipped for all ground conditions. We use multiple drilling methods including air, air/mist, water and drilling muds. For particularly poor or unstable ground, we offer simultaneous drilling and casing methods to stabilise the borehole as it is drilled, to a maximum finished depth of 150 metres. 15m of metal casing through soft surface material is included as standard in our pricing.
Borehole drilling is an industrial process and does generate noise — the rig and compressor are the main sources. Noise levels are comparable to other construction activities. We work during standard hours and can discuss scheduling with you or your neighbours if noise sensitivity is a concern. Drilling a typical 100m borehole takes around one day.
Ready to Start Drilling?
Get in touch for a drilling quote or to discuss your project requirements. Whether it's a single domestic borehole or a multi-property ground array, our in-house team has the rigs, experience and capacity to deliver.
Part of our Partner Installer Network? Contact us for trade pricing.
Ready to Start Drilling?
Get in touch for a drilling quote or to discuss your project requirements. Whether it's a single domestic borehole or a multi-property ground array, our in-house team has the rigs, experience and capacity to deliver.
Part of our Partner Installer Network? Contact us for trade pricing.