How to Build Foundations on Difficult Sites
For many developers, awkward or ‘tricky’ plots of land are best avoided. They can lead to huge groundwork costs, lengthy project delays, and lots of uncertainty. In other words, they’re a bit of a gamble. Without the right strategy, team, and equipment in place, it is a gamble that isn’t guaranteed to pay off.
Yet, there are many reasons why tricky plots are worth the risk. Houses built among lots of greenery, particularly trees, are highly valuable. The foundation work can be complex because tree roots have a tendency to weaken the soil. When successful, though, these projects are among the most prized and beautiful.
So, a tricky plot of land shouldn’t spell the end of your development dreams. However, you may need to think about investing in reinforced ground beams.
Understanding the Basics
The problem with traditional trench foundations is that they start to become really inefficient beyond 2cm in depth. This means that, in unstable or weakened soil, something a little more advanced is needed to hold the structure in place and prevent movement of the ground.
The first thing that you should do, after having problems with the soil diagnosed, is consult with a structural engineer. Find a reliable (preferably local) provider of reinforced ground beams. With their support, you’ll be able to start planning around the vulnerabilities and create a foundation strategy that safely accommodates them.
It is important to remember that non-conventional foundations will always be more costly than the traditional methods. They’re also likely to result in a slightly longer project timeframe. On average, the application of reinforced ground beams adds between 7-14 days to the foundation stage. However, this is something that you should discuss with your provider.
How Reinforced Foundations Work
Concrete columns called piles are inserted deep into the ground until they reach the firmest bedrock. They can then be used to anchor the structure to the earth, without fear of shifting or movement. Over the years, the method has become much more popular, because short bored systems are less expensive than they were.
It is currently the second most popular foundation building technique, after standard trench foundations. It works by positioning piles beneath the primary walls, corners, and intersections, at intervals of around 2.5 metres. Once they are sturdy and secure, pile caps are added on top, so that the piles can carry the reinforced ground beams.
The Impact of Your Construction System
On land where the load bearing support is found fairly deep within the earth, piled foundations are the safest and most economical solution. They are a suitable choice, for example, on made up ground, shrink-prone clays, or soil that contains deep rooted vegetation. If the land is deemed to be very insecure, a reinforced concrete raft can be used to, essentially, ‘float’ the foundations. This puts less pressure and strain on unstable ground.
It is important to work closely with your lead engineer and foundation building team because the method chosen will depend on how you want to erect the structure. For instance, traditional masonry walls are best used in combination with conventional raft or trench foundations. On the other hand, pile foundations are a viable option for both masonry and timber structures.