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How Deep Do Foundations Need to Be for a Conservatory?

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Date : May 11, 2023
“How Deep Do Foundations Need to Be for a Conservatory?”

Conservatories, in most cases, do not require planning permission. However, care should be taken in the design phase. This is because, once walls are a certain height, the conservatory would be classed as an extension and would in this case need planning permission.

If the planned conservatory is at ground level and separated from the house by quality doors and windows then it will not be subject to building regulations. If the new construction’s footprint is over 30 square meters, then seek advice about permissions.

When it comes to the foundations of a conservatory, it is not always clear how deep they need to be.

Here’s some advice on conservatory foundations from Orangeries UK:

How important are conservatory footings?

As with any new structure, the conservatory will only be as strong as its foundations. Well prepared and laid foundations can make the construction easier. The foundations will avoid any future structural failings or possible subsidence.

How deep do foundations need to be?

The minimum depth of foundations required for a conservatory depends on several factors, including the size of the conservatory, the type of soil, and local building regulations. It is important to consult with a qualified structural engineer or a building professional to determine the specific requirements for your project. Obviously this will affect the conservatory building costs but corners should never be cut with foundations.

That being said, as a general guideline, the minimum depth of foundations for a conservatory is typically around 1 meter (3 feet). This depth helps provide stability and prevent settling or movement of the structure. However, it’s important to note that this is a rough estimate, and the actual depth may vary depending on the specific circumstances of your project.

To ensure proper foundation design, it is recommended to consult with professionals who have expertise in construction and building regulations in your area. They will be able to assess the soil conditions, consider the weight and design of your conservatory, and provide specific guidance on the minimum depth of foundations required.

Good foundations will guarantee years of pleasure from your conservatory. It is important to have professional advice on the foundation depths for your new conservatory.

How to build a conservatory?

For maximum strength, the trench should be filled with concrete, with additional consideration given to any drains or pipework exposed during excavation. Steel reinforcement can be used to strengthen the concrete over drains. A brick cavity base wall will be built onto the foundations, using concrete lintels over any pipework and insulated, as it would be in house construction.

The base within the conservatory will be formed by a layer of hardcore. It will then be concreted over, insulated and feature a damp proof membrane. The floor will then have a screed finish ready for the chosen flooring to be laid on.

Are the foundations essential?

Whilst it is possible to build a conservatory without foundations it is not generally recommended, regardless of whether there is a dwarf wall or not.

The construction’s base need not always be concrete. A wooden conservatory base could also be used. This would be constructed from heavy duty, treated timber. With a fixed outer frame, joists would be hung, braced at intervals and secured by joist hangers. A well constructed wooden base could be just as strong as concrete. This might be used to keep costs down where the conservatory has extended over sloping ground.

Another option is a metal base, constructed in a similar fashion to wooden bases. These will also have the advantage of covering awkward ground to lay a concrete base on.

There are also self build conservatory kits available. These aren’t just for simple lean-to conservatories, a confident DIYer can construct an elaborate conservatory. Care should be taken to ensure that footings and any supporting walls are constructed to the exact dimensions and specifications to accommodate the structure.


Whatever your conservatory ideas, here at Orangeries-UK we can offer support and advice for planning you conservatory. We offer a fabulous range of conservatories and orangeries to give your home the wow factor.

Conservatory Building Regulations – All You Need to Know

When building a conservatory, it is important to adhere to industry standards and regulations to ensure safety, structural integrity, and compliance with local building codes. While specific regulations can vary by region, here are some general guidelines that are commonly followed:

Building Regulations:

In many countries, including the United Kingdom, there are specific building regulations that apply to conservatories. These regulations cover areas such as structural stability, thermal performance, ventilation, fire safety, and accessibility. It is crucial to consult with local building authorities or a qualified professional to understand and comply with the applicable building regulations in your area.

Planning Permissions:

Depending on the size, location, and design of the conservatory, you may need to obtain planning permission or comply with permitted development rights. These permissions ensure that the construction aligns with local planning regulations and does not significantly impact neighboring properties, the environment, or the overall aesthetics of the area. Check with your local planning department to determine the requirements.

Structural Design:

The conservatory should be designed by a qualified architect or structural engineer who can assess the load-bearing requirements, including the weight of the structure, glass panels, and any additional features. The design should account for wind and snow loads, as well as potential subsidence or ground movement, depending on the soil conditions in your area.

Glazing and Thermal Performance:

The glazing used in the conservatory should meet relevant standards for safety, such as impact resistance and shatterproofing. Additionally, energy efficiency and thermal performance requirements may apply, specifying factors like U-values, which measure heat transfer through the glass. Compliance with these standards helps maintain a comfortable temperature and minimize heat loss.

✅ Electrical and Plumbing Regulations:

If the conservatory incorporates electrical wiring, lighting, or plumbing systems, it is essential to follow the applicable electrical and plumbing regulations to ensure safety and compliance. This may involve using certified electricians and plumbers and adhering to specific installation and safety standards.


Consideration should be given to accessibility standards to ensure that the conservatory is accessible for individuals with disabilities. This may involve provisions such as ramp access, wide doorways, and appropriate flooring materials.

These are general guidelines, and the specific regulations and standards can vary depending on your location. It is crucial to consult with professionals experienced in local building regulations and seek the necessary approvals before starting construction on your conservatory.

Author:  Daniel Foley Carter


Daniel Foley Carter has 10 years of experience in the joinery and wood fabrication sector. Daniel has written for major publications such as House and Home, Timber Weekly, and Construction UK. Daniel has worked with a large number of construction and woodwork projects and has extensive experience with wood properties, wood selection, and the utilization of wood in home extensions and construction.


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