What is a screw pile foundation? 

A screw pile foundation is a high strength steel shaft fitted with helical blades that are screwed into the ground using specialised hydraulic equipment. Each shaft is installed to a predetermined depth and torque, which transfers loads to competent load-bearing strata, which may include dense soils, weathered rock or bedrock depending on site conditions.  

Although the term helical pile foundation is often used interchangeably with screw pile, they both refer to the same technology. The terms can vary between regions or even suppliers, but the benefits are the same. Screw pile foundations are typically used for: 

• Garden rooms, offices and outbuildings

• Extensions and conservatories

• Decking and raised structures

• Retaining walls and garden fences

• Slopes or floodplains

Screw piling doesn’t require excavation or concrete, which makes them ideal for projects where speed, precision, and minimal site disruption matter. 

Understanding Ireland’s challenging ground conditions 

What makes Ireland’s geology so challenging for foundations? 

• Poor load bearing capacity or weak soil types: Ireland is dominated by variable soils, which poses challenges for property foundations. Peat soils, which are known for their low load bearing capacity and high compressibility, cover approximately 23% of Ireland's land area. Clay soils also present a challenge because of its shrink-swell cycle. Challenging ground conditions have a significant impact when it comes to selecting a foundation system.

• High and variable water tables: This is another common problem through Ireland low-lying central area. Saturated ground with water table levels close to existing ground levels makes excavating foundations challenging. These conditions may mean that the area needs to be drained and may require more extensive remediation works, leading to higher costs and more time on site.

• Variable terrain: Glacial features such as drumlins and glacial moraine create sloped and hilly landscapes and are common across much of rural Ireland. Traditional strip or raft foundations on sloping ground typically require extensive levelling, retaining structures, or deep excavation to reach competent, load-bearing soil.

These conditions call for an alternative approach to conventional foundation design and in such situations screw piles can offer a cost effective and viable solution. 

Why screw pile foundations perform well in Irish soils 

What makes screw piles ideal for challenging Irish soils? 

The helical plates transfer load through a combination of end bearing and shaft resistance. This allows the pile to reach competent, load-bearing soils deep into the ground without the need for extensive excavation; even where soil quality variation occurs over relatively small areas. 

Additionally, the installation work doesn’t require in-situ concrete. This ensures that there is no need to undertake extensive de-watering works to gain access or improve soil conditions. Screw piles are installed using easily transportable and relatively lightweight equipment. Such plant can access sloping sites that would be difficult to reach with traditional groundworks machinery. 

The benefits of choosing screw piles in Ireland 

For homeowners and developers, screw piling offers significant benefits. 

Getting professional advice 

Since ground conditions can vary significantly, a thorough assessment of soil type and the ground’s load-bearing capacity is vital before remedial works take place.  

Mainmark’s ground engineering specialists work with homeowners and developers to assess soil conditions and identify the most appropriate method of remediation works. In areas where subsidence, soft soils or ground movement are a cause for concern, Mainmark can improve site conditions through non-invasive techniques including screw piling and resin / geopolymer injection solutions. Mainmark specialises in the design and installation of all such foundations, with each installation designed following a detailed geotechnical assessment to determine the correct pile design for optimal performance. 

A practical solution for modern Irish construction 

With much of Ireland’s landscape dominated by soft ground, clay-rich soils and high-water tables, screw pile (or helical pile foundations) offers a practical, flexible alternative to many traditional concrete foundation systems. Screw piling is a less disruptive method that’s faster to install and ideally suited for a range of projects. 

If you're planning a new extension or garden room and want to understand whether screw pile foundations are suitable, get in touch with Mainmark Ireland today.