Shelter on existing retaining walls: what is possible for a silage clamp?

Do you already have a silage clamp with concrete retaining walls? In many cases, it is possible to install a shelter on top of those existing walls. The key condition is that the walls must be strong, stable and thick enough to anchor the shelter safely.

In this blog, we explain when an existing silage clamp is suitable, what to pay attention to and how you can extend it with a standard shelter.

Can a shelter be installed on existing retaining walls?

Yes, this is often possible. A Kroftman shelter can be fixed to the retaining walls using concrete anchors. That is why the quality, thickness and load-bearing capacity of the walls are especially important.

The existing wall must provide enough space for safe anchoring. If the wall is too narrow, the anchor will be too close to the edge. Under heavy wind loads, this may cause the concrete edge to break out. In practice, a wall thickness of around 210–220 mm is often considered the lower limit.

When is it likely to fit?

The chances are highest when:

1. The retaining walls are thick enough for anchoring. If the wall is too narrow, the anchor will be too close to the edge.

2. The walls are stable, straight and square, without cracks, subsidence or crumbling edges.

3. The walls do not have a rounded top.

4. The silage clamp matches a standard width of 4, 6, 8, 10, 12 or 15 metres.

5. The shelter can be placed properly in the centre of the wall.

6. Few additional adjustments are needed to the existing structure or surroundings.

Also pay attention to height, wind and snow loads. A high or narrow wall can create extra risk. This is especially the case on open sites, near water or in coastal areas.

In practice, this means that a silage clamp may fit in terms of dimensions, but may still need an additional structural assessment. The combination of wall, anchors and wind load largely determines whether installation is safe.

A solution with a standard shelter

Our bunker silo shelters are available in standard widths of 4, 6, 8, 10, 12 and 15 metres. The length is modular, starting from 6 metres and extendable in 6-metre sections.

Does your silage clamp fit within these standard dimensions? Then custom work is not needed, and the solution remains more cost-effective.

Custom solutions are often possible, but require additional engineering and therefore involve extra costs. Read more about our custom options here.

Want to know more about our custom options?

Read more

Also check the maximum wall height

When assessing the situation, we do not only look at the width, length and thickness of the retaining walls. We also look at the height of the wall. Our calculations are based on a wall height of up to 2.90 metres.

For the larger arched roof shelters of 12 and 15 metres, the calculation allows for a higher setup of up to 5.80 metres, comparable to two containers stacked on top of each other.

Is your existing silage clamp higher than these assumptions? Then each situation must be assessed separately to determine whether the shelter can be installed safely from a structural point of view.

What if the retaining walls are not heavy enough?

Sometimes the wall is suitable for installation, but additional weight is needed. In certain situations, extra concrete blocks placed against the side wall may be considered. This must always be assessed structurally for each project.

A standard shelter is often the most economical solution, but safety always comes first. A strong shelter on a weak wall is not a safe solution.

What about wind load?

Wind load is an important point of attention, especially when the opening of the silage clamp faces the wind. Kroftman shelters are calculated according to the European standard EN 13782. This takes both wind and snow loads into account.

When installing a shelter on existing retaining walls, it is not only the shelter that must be strong enough. The concrete structure underneath must also be able to carry the load safely.

Want to know exactly what EN 13782 means for your shelter?

Read more

Is a permit required?

That depends on the location, dimensions, use and local municipal regulations. Especially in agricultural applications, this must be assessed case by case.

For our standard shelters, a construction manual is available. It includes the technical drawings and calculations. This can help in discussions with the municipality or when applying for a permit.

What information do we need?

To assess whether a shelter can be installed on your existing silage clamp, we would like to receive:

• the width, length and height of the silage clamp;

• the thickness of the retaining walls;

• the centre-to-centre distance between the retaining walls;

• photos of the current situation, especially of the top of the walls;

• location details in relation to wind load;

• any drawings or structural information about the concrete walls.

Conclusion

Installing a shelter on existing retaining walls is often possible, but not every silage clamp is automatically suitable. The thickness, stability, height and condition of the concrete walls determine whether the shelter can be anchored safely.

That is why it is important to measure the silage clamp first and check the condition of the walls. Wall thickness, wind load and anchor positioning are especially important. If the silage clamp fits within a standard size, the solution usually remains simpler and more cost-effective.

Not sure whether your silage clamp is suitable? Our sales team will be happy to take a look with you.

Contact us