The 12 Steps of Self Build: Groundworks & Foundations

This month we look at the essentials of groundworks — basically, everything that goes on a building site below ground level. Generally the groundworks will cost between 10 and 15% of the final build cost, but this figure can rise appreciably on difficult sites — sometimes as much as doubling. So there is an appreciable financial risk associated, and managing groundworks is all about managing this risk. As ever, thorough planning is the key, plus having a healthy contingency sum to hand in case of emergency. In this article we explain the main issues you need to consider, along with a few key questions you should ask yourself.

Ask Yourself This...

Before starting work on site, there are some important questions you need to find the answers to in order to ascertain what, if any, action needs to be taken:

Trees

• Are there any significant trees on site, and if so what species – and how big – are they?
• Are there any on adjoining land that may affect you?
• Are any Tree Preservation Orders in force on your plot?

Ground conditions/ Subsoil

• Is there ground water or signs of a high water table?
• Is the plot shown on flood plain maps?
• Does the ground consist of rock or heavy clay?
• Are there any streams/watercourses?
• Are radon gas precautions necessary?
• Any sign of local buildings employing special foundations?
• Is there any evidence of filled ground?
• Any existing foundations?
• Is the ground sloped?

Find out more:

• Groundworks & Foundations: Excavations
• Groundworks & Foundations: Foundations
• Groundworks & Foundations: Ground Floors
• Groundworks & Foundations: Drainage
• Groundworks & Foundations: Rainwater Management

The 12 Steps of Self Build:

• Step One: Starting Out
• Step Two: Your Route
• Step Three: Construction Systems
• Step Four: Groundworks & Foundations
• Step Five: Roofs
• Step Six: Windows & Doors
• Step Seven: External Appearance
• Step Eight: Heating & Plumbing
• Step Nine: Electrics
• Step Ten: Kitchens & Bathrooms
• Step Eleven: Internal Finishes
• Step Twelve: Outside Spaces