📋 Key points: Personally, I believe that 80% of veranda problems come from poorly prepared ground. I’ve seen too many projects fail due to initial negligence. The 5 essential tips ensure a solid foundation for 20-30 years of lifespan.
You are tempted by the installation of a veranda. You have a suitable plot of land and have gathered enough information about administrative procedures. With the price of a veranda, you have the necessary budget to realize the project.

To carry it out successfully, it is better to entrust it to a professional. If you are not in the trade, nothing prevents you from learning about masonry work. This article provides details on ground preparation before the installation of the veranda.
🗣️ My experience: Last year in Lyon, I prepared a plot for a 15m² veranda neglecting drainage, costing an extra €800 to fix. The lesson: always test water infiltration upstream to avoid damp rising.
Preliminary steps before installing the veranda
✅ Advantages
- Prevents 90% of cracks
- Quick installation
- +25% real estate value
👎 Disadvantages
- High initial cost
- Heavy work
Choosing the right ground:
So that you can fully enjoy your veranda, the selection of the ground should not be taken lightly. Your goal is to make it a pleasant place to live.
To achieve this, it is useful to protect it from the sun. The sun should warm and illuminate it for optimal comfort. So think about its orientation.
For those in cold areas or in the north of France, a South exposure is strongly recommended. This allows them to benefit from the natural warmth of the sun during the day.
If you live, on the other hand, in warmer regions or in southern parts, you can opt for East or southeast exposure.
The latter helps you enjoy the morning sun rays and benefit from some shade when it gets extremely hot.
To go deeper, I recommend veranda materials which complements this topic well. veranda price also provides useful insights. And to go further, extension obligations offers interesting perspectives.
Carrying out earthworks:
After you have chosen the orientation of the veranda, the next step is to carry out the earthworks. These works play a crucial role as they ensure the strength and stability of the construction.
This operation consists of clearing the land of clay, glass, rocks, and any other material that could cause imbalance. It must be done before pouring the slab.
So that the veranda does not slip or sink, the concrete slab must be poured entirely into an excavation. It should be noted that its depth depends on the shape and surface area of the future room.
Aside from the earthworks or leveling operation, electrical installation can also be carried out. The electrician must follow the plan of the craftsman or mason in charge of the work in order to jointly determine the electrical supply points.
⚠️ Common mistake
Neglecting soil compaction: the ground sinks under 5 tons of veranda, causing imbalances and leaks. Always use a vibrating plate in successive passes.
Properly insulating the floor:
Before installing the veranda, make sure to ensure floor insulation. Between the excavated earth and the slab, it is recommended to install compaction plates or a waterproof coating. They help eliminate problems of moisture and infiltration.
Take the necessary measures to avoid a possible thermal bridge. Specialists often install a strip of bituminous felt. It should be remembered that poor ground insulation can be difficult to repair.
| Step | Required tool | Average cost (€) | Estimated time (h) | Minimum depth (cm) |
|---|---|---|---|---|
| Excavation | Mechanical shovel | 500-1500 | 8-12 | 30 |
| Leveling | Laser level | 50-100 | 4-6 | – |
| Drainage | PVC pipes Ø100 | 200-400 | 6-10 | 40 |
| Compaction | Vibrating plate | 100-200/day | 2-4 | – |
| Concrete slab | Concrete C25/30 | 80/m² | 24 (drying) | 12 |
🌍 Did you know?
A veranda on undrained ground sees its maintenance cost double in 5 years due to cracks caused by frost, affecting 40% of poorly prepared installations.
Pouring the slab:

Once you have properly dug the foundations and ensured insulation, you can now pour the slab.
It is made up of many materials, namely an insulator, a polyethylene sheet, and welded meshes intended for reinforcement. The whole is about 20 cm thick.
If you want to provide a solid base for the veranda, concrete footings will be perfect for you.
This is a concrete block designed to accommodate a post.
To do this, install the slab in a previously dug hole. Then, place the concrete footing on top. All that remains is to fix the post to it. Thanks to this method, the new piece will be firmly planted in the ground.
In general, assembling the veranda takes between 2 and 3 days. However, this timeframe relates to the standard model. For a large extension, you will need several days or even a week. The same applies to verandas made with delicate materials.
🔧 Tip
Compact in layers of maximum 20cm, water to 95% Proctor density. Mix concrete at 350kg/m³ for a reinforced slab 12cm thick.
Finishes:
After the foundations and the installation of the slab as well as the veranda, you can carry out the finishes by laying the floor covering. You have a choice of various materials such as parquet, tiles, and much more.
If necessary, take the opportunity to do the painting. Consider installing heating, shutters, blinds, or any other shading equipment.
Main advantages of a veranda
Whether made of PVC, steel, aluminum, or wood, the veranda allows you to gain space in your home.
It is an ideal solution to shelter your plants during winter. If you want to enjoy the outdoors while savoring your meals, it can very well replace your dining room.
| Advantage | Description |
|---|---|
| Space extension | A veranda allows you to enlarge your house by creating a new bright and friendly room. |
| Natural light | Thanks to its large glazing, the veranda brings a large amount of natural light into the house. |
| Comfort all year round | With good insulation and suitable glazing, it offers a pleasant living space in all seasons. |
| Increase in property value | Adding a veranda increases the value and appeal of your property on the market. |
| Customizable aesthetics | Available in several materials and styles, the veranda adapts to the architecture of your house. |
| Versatility of use | It can serve as a living room, dining room, office, winter garden, or relaxation space. |
| Natural heat gain | The veranda captures the sun’s heat, helping to heat the house passively. |
Some households convert it into a kitchen, others arrange it to become an office or a friendly space just to relax. In any case, the veranda offers you a few extra square meters.
In terms of aesthetics, it helps beautify your home. With a successful design, the extension plays a decorative role enhancing the exterior appearance of the dwelling. To maintain its original condition, it is advisable to maintain it regularly.
If you have a pressure washer, you will be able to easily clean the windows as well as the roof. The latter becomes covered with moss over time. The device can remove it even without using specific products.
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This step can prove crucial as it ensures the stability of the extension. Otherwise, it risks tipping over the years. Preparing the ground thus guarantees its lifespan.





