Building Foundations Near Water: Solutions for Waterside Construction

Water has a mind of its own. Build near it, and you quickly learn that conventional foundation logic goes out the window. 

Whether it’s a deck overlooking the lake, a riverside cabin, or perhaps a boathouse, water introduces variables that complicate even the most straightforward projects.

Luckily, there are a few creative foundation solutions for waterside construction. 

This guide explores real solutions for waterside construction foundations. We’ll compare methods that work when water is involved – from floating systems to stilts to ground screws – and explain when each suits your specific project.

What Are You Building Near Water?

Chances are, you’ve got a specific project in mind – something close to water that needs a solid foundation. 

Whether it’s for leisure, work, or something in between, here are some of the most common projects we see along lakes, rivers, and ponds:

• Deckings and platforms: Great for relaxing by the water, setting up a BBQ, or creating a social space. Deckings can extend over or sit right beside the bank or shoreline.
• Boathouses: Can be simple storage for boats, or include a clubhouse or other features. Often built across both land and water, which makes foundation planning more interesting.
• Garden rooms and cabins: Ideal for a quiet workspace or seasonal retreat. Waterside garden room builds take advantage of the view but need to be sturdy through all kinds of weather.
• Fishing shelters: Ranging from covered benches to more substantial structures with seating and storage. Popular on both private properties and commercial lakes.
• Boardwalks and walkways: Help you move safely across marshy ground or along the water’s edge. These can be residential or part of larger public or natural areas.
• Steps and landing stages: Smaller builds like stairways down to the water or boat access points – but they still need to handle movement, moisture, and shifting soil.

Whatever you’re working on, one thing’s certain: building near water is not just business as usual. So — let’s talk about laying the ideal foundations when water’s part of the picture.

Your Foundation Options When Water’s Involved

Building near water brings its fair share of quirks and nuances to the table. Each method has strengths and annoying limitations. Here’s what to consider for your plans:

1. Traditional Concrete Base

The old faithful of construction. Dig a hole, pour in concrete, job done. Except when water’s involved, it’s rarely that simple.

You’ll need to excavate the site (tough work if it’s already wet), possibly add steel reinforcement, and then pour concrete that needs proper curing conditions.

On the upside, concrete can handle hefty loads once it’s properly set. It distributes weight evenly, and most builders are familiar with working with it. 

However, you’ll need dry weather for installation and access to heavy machinery without sinking into soft ground. Then there’s the environmental angle – concrete runoff isn’t exactly friendly to aquatic ecosystems and may not be permitted depending on local planning and environmental regulations. 

Even if all is well, post-installation, the shifting ground underneath can still crack your base within months.

2. Concrete Block Piers

Instead of pouring a complete base, you’ll create support columns at strategic points. Less concrete is used, and there’s better drainage between piers.

This works well for smaller structures, such as modest decks or simple sheds. You can adjust pier heights to handle sloping ground without excavating the whole area – handy on a riverbank with a gradient.

The catch? Getting every pier perfectly level is tricky. And if one pier settles faster than others over time (which absolutely happens near water), your whole structure twists. 

3. Floating Platforms

Instead of fighting the water, why not float on it? Pontoon systems support structures directly on the water surface, rising and falling with water levels. 

The beauty is that these systems adjust automatically to water level changes. No mechanical systems, no adjustments needed. They have zero impact on water flow patterns, and they’re movable if your plans change. 

You’ll need to watch your building’s weight to not exceed the buoyancy limit. 

Overall, while a niche option that suits some installations, floating platforms are not widely applicable. 

4. Elevated Stilts

The classic waterside solution. Jack your building up on posts, keeping it high and dry above the fluctuating water level. It’s straightforward, creates useful space underneath, and handles flooding well.

As for limitations, weight capacity depends entirely on post strength and ground conditions. In highly soft soil, even strong, substantial posts can start to tilt over time, as they don’t tend to anchor well unless driven extremely deep below the water line. 

5. Ground Screws

Instead of just sitting on the ground or being hammered in, ground screws are driven deep into the soil, their design anchoring properly in the soil. 

The helical plates along the screw shaft cut through different soil layers and compact the ground around them. Once installed, they create exceptionally stable points that resist both downward pressure and sideways forces – similar to stilts in principle but far stronger and more resilient. 

Installation is simple and doesn’t require heavy machinery. You can adjust heights above ground for perfect levelling. Like stilts, they suit areas where environmental preservation is important or mandatory. 

Why Ground Screws Work Near Water

Of all these options, ground screws offer something genuinely different for waterside building. They deliver stability without massive ground disruption, which can be decisive. 

Here’s an exploration of why they work where other methods struggle:

Ground Screws Handle Weather Disruptions

You’ve scheduled work, hired people, ordered materials… then the rain arrives. With traditional foundations, that often means delays – pack up and try again when conditions improve.

Ground screws are only limited by the tenacity of the installation team itself (and we’ve installed them in all sorts of conditions…). Wet ground and additional moisture don’t significantly affect the process. This resilience means:

• No more cancelled installation days due to rain
• No rushing to finish before forecasted downpours
• No waiting for ground to dry out before you can start
• No concrete curing times that extend in damp conditions

Ground screws’ reliability completely changes how you plan waterside projects – you can schedule with confidence and stick to your timeline.

Ground Screws are Gentle on Banks and Shorelines

Waterside areas are often environmentally sensitive. Banks erode, wildlife habitats need protection, and heavy machinery may not be permitted. Concrete is often forbidden or strictly controlled for waterside construction as it’s highly alkaline and leaches into the waterways. 

Ground screws pose no such issues, and the equipment needed to install them is lightweight compared to concrete mixers and excavators. This means:

• No damaged access paths that turn to mud
• Reduced risk of bank instability during installation
• Minimal soil disturbance that could lead to erosion
• No concrete spillage contaminating water

Interestingly, ground screws often strengthen the surrounding soil rather than weakening it. The spiral plates compress the ground as they go in, creating a denser, more stable environment around each screw.

Ground Screws Start Working Immediately

Time matters in construction, especially near water, where conditions can change quickly.

Ground screws can bear weight the moment they’re installed. This instant load-bearing capacity means:

• Start building the same day foundations are installed
• Reduced exposure to weather changes during the critical early phase
• No waiting to see if curing concrete gets damaged by unexpected rain
• Faster project completion from start to finish

This immediacy compresses the construction timeline and actively reduces risk in waterside environments where conditions can change rapidly.

Ground Screws Can Be Fine-Tuned Even After Installation

Unlike concrete, which is permanently fixed once set, ground screws offer ongoing adjustment potential. The brackets connecting to your structure can be adjusted to maintain a perfect level, even if ground conditions change.

This proves invaluable for waterside structures where:

• Seasonal water level changes affect the surrounding ground
• Erosion gradually alters the landscape
• Freeze-thaw cycles cause ground movement in winter
• Settlement occurs unevenly across the site

As ever, all of these benefits and others hinge on proper installation. So let’s take a walk through some tips for ensuring successful waterside ground screw projects. 

Installation Tips for Waterside Ground Screws

Installing ground screws near water needs a bit of extra thought. Here’s what makes the difference between a successful installation and one that causes issues down the line:

Know Your Water Levels

Water levels change seasonally, with rainfall, and even by the time of day in tidal waterways. Before installation, check:

• Historical high-water marks on nearby structures
• Local knowledge about seasonal flooding
• Environment Agency flood maps
• Seasonal water table variations

Robust research helps you choose the right screw length and positioning. In flood-prone areas, longer screws anchored into deeper, more stable soil layers provide extra security when water rises.

Plan Site Access Carefully

While ground screw installation tools are lightweight, moving installation equipment to the waterside without damaging the surrounding environment still takes planning. Look for:

• Firm access points that won’t get churned up
• Existing paths that can handle light machinery
• Areas where temporary protection can be laid down

If a bank shows signs of previous movement or erosion, it’s often wise to position screws slightly back from the edge where ground is more stable. Remember that preserving bank integrity is crucial for long-term site stability.

Test Before You Commit

Thorough testing helps ensure proper screw selection:

• Trial screws check soil resistance at different depths
• Soil sampling identifies hidden clay or sand layers
• Load testing confirms weight-bearing capacity

Testing isn’t a bureaucratic ordeal – it offers insurance against future problems, especially when you’re installing heavier buildings. 

Consider Professional Installation

While ground screws are easier to install than concrete, waterside locations leave little room for error. Depth and angle matter, especially in variable ground conditions.

Professional installers like our team at GSC bring:

• Experience in reading waterside ground conditions
• Specialist equipment when difficult access poses issues 
• Knowledge of correct screw types for specific challenges
• Precise levelling techniques for uneven terrain

This can be absolutely vital for a waterside project, as it’s not quite as easy as setting up in a dry back garden!

Get Started with Ground Screws From GSC

If you’re building near water, ground screws are a practical, no-fuss alternative to concrete. They’re quick and effective to install, work in soft or wet ground, and keep disruption to a minimum – ideal for banks, shorelines, or anywhere access is tricky.

Here’s how GSC can help with your project:

• Online calculator: Work out what size and how many screws you’ll need for your project.
• Browse the range: We supply reliable ground screws and brackets, built to handle varied ground conditions and changeable weather.
• Installation and testing: We offer professional fitting and load testing if you’d rather leave it to the experts.
• Need advice? Just ask. Let us know what you’re building and where – we’ll help you find the right setup for the site.

Foundations by water don’t have to be complicated. With the right kit – and a bit of planning – you can get a solid base in quickly, without churning up the environment or waiting for dry weather.