How to determine if a plot of land is buildable?

*Update: Please contact our team for current pricing.

Today, we explain how to determine if a plot of land is buildable. Purchasing land is a significant investment many families undertake as a life project after years of saving or selling a house or apartment – and it is crucial to buy with full assurance of its buildability.

In our studio, we offer free advice for pre-purchase land review. Over the years, we have encountered all sorts of situations that complicate the legal or technical viability of building on a plot of land.

From issues with the municipal council’s acceptance of the urbanization and the consequent problems with obtaining building permits, to technical complications due to steep slopes and poorly cohesive soils that make foundations unfeasible or so complex that costs skyrocket. Many aspects need to be reviewed, and it is important to be well-informed or to consult with a competent professional.

Although we offer free advice, which for us is a way to initiate contact with clients and ensure we proceed to the project phase with a suitable plot, today we summarize the key points to consider. Of course, you can contact us if you have any questions or would like our assistance with the review.

Prior Consideration: Financial Feasibility

Before starting the technical and legal review, it is important to consider the financial viability of our project.

We always recommend to all our clients that before starting to look for land, it is necessary to go to the bank and confirm the available investment, combining personal savings and financing. To give you an idea, the investment for a 100 m² house is around 350,000 euros, including design, construction, and taxes – regardless of the company you contract with.

It is also important to know that today, banks do not finance or mortgage land, so the first thing we need to be clear about is that to buy a plot of land, we must be able to cover the purchase with our own capital.

There is an alternative: having 20% of the total operation (land purchase + house construction) available. In this case, the bank can assist with the land purchase. However, this option depends on presenting a certified project with a building permit to the bank for land financing, which can take several months and must be agreed upon with the land owner in the earnest money contract.

Finally, we must consider that a plot of land incurs approximately 12% in taxes if it belongs to a private individual, and 21% VAT if it belongs to a company such as a developer or a bank.

Once the investment is clear, it’s time to start looking for land within our price range. Generally, the price of the land should align with the amount we have saved.

We recommend reviewing our article Basic 3-Step Guide to Finding Land.

To assist you with land review, the aspects to consider will be divided into 3 distinct groups: technical, administrative, and legal.

How to Determine if a Plot of Land is Buildable: Technical Aspects

Before describing the technical aspects when asking how to determine if a plot of land is buildable, we must emphasize the three temporal stages of the land review procedure: general pre-visit checks, checks with the municipal council, and general checks during the visit.

Thus, technical aspects refer to the physical characteristics of the land, and will therefore be addressed primarily during the visit itself. We divide these aspects into 5 main concepts that will affect the possibility of building on the land: sun exposure, topography, geology, urbanization, and services.

Sunlight

Sun exposure refers to the amount of sunlight the land receives, and therefore how much we can capture inside our future home—a crucial need when discussing bioclimatic architecture.

If we are looking to build an ecological, zero or near-zero energy consumption home, direct sun exposure for most of the day will be essential to ensure optimal climatic performance for our future home.

The characteristics of this sun exposure are governed by the orientation of the land; in the northern hemisphere, a south orientation is ideal. The larger the south-facing facade or side of our land, the better. Other good orientations include southeast or southwest.

Similarly, the presence of obstacles that prevent sunlight from reaching the plot negatively impacts solar incidence. In general, an ideal plot is flat with no surrounding obstacles, a situation that gives us free rein to orient our project as desired.

While we often emphasize the importance of solar protection in our climate for achieving thermal comfort in summer, it is always possible to add protection. However, it is not possible to add sun to a plot that lacks it.

Another factor to consider is that a good south orientation combined with an effective layout of our rooms, creating north-south cross-ventilation, will allow us to naturally cool the house in summer.

Topography

The topography of the land primarily refers to any slopes it may have. Excessive slopes represent a significant disadvantage for the construction of the future property, as earthmoving work and additional foundation costs will substantially increase the budget for our future home.

A tip for approaching the design of a house on a sloping plot is to prioritize plots with access from above to minimize the costs of ramp construction, which are often economically unfeasible today, and to facilitate access, as we typically want to place the house at the top for views and sun.

A topographical study is conducted once the land has been purchased and costs around 300-400 euros. If there are doubts about the implications of a steep slope on the final project cost, it is advisable to consult a professional who can visit the site before purchase.

Geology

Again, the economic aspect becomes important when studying the geology of our land, which requires a geotechnical study costing around 800 euros, usually performed after the land has been purchased. This study could be carried out beforehand, or at least some preliminary soil tests, if there are doubts about the construction viability of the land.

Land that cannot support sufficient loads, with poorly cohesive soil or where the resistant stratum is at great depth, can lead to additional foundation costs that, in some cases, might make construction unfeasible.

The geological study will define the morphology of the land, detailing the arrangement and characteristics of the soil layers present, as well as the presence of water.

What interests us most will be the depth at which we can find a sufficiently resistant substrate to support our foundation. With the information from the study, we will have enough data to define the type and dimensions of foundations and retaining structures, as well as their economic cost.

Regarding water, it will be essential to know the depth of the water table, as building below it exposes us to risks such as water infiltration or internal erosion.

Similarly, foundations also suffer in contact with water, which can destabilize and cause differential settlement of the structure.

If we have doubts about the resistance of the land, an alternative to performing a complete geotechnical study (which is usually not done until after the land purchase) would be to conduct a test pit to determine the depth of the resistant stratum. These test pits can be carried out by the same geologist who will later perform the full study.

Finally, a good recommendation is always to ask neighbors who have already built nearby houses what type of subsoil they encountered to get a preliminary idea of potential problems.

Urbanization

When considering how to determine if a plot of land is buildable, it is important to check the urbanization status of the street.

Economically, plots located in undeveloped areas are typically subject to urbanization charges from the municipal council, as we will detail later in this article, which will imply an increase in the budget that we must take into account.

Furthermore, there may be situations where a street re-urbanization is planned, either to renew an existing service, bury it, or improve the accessibility of road surfaces and pavements. Therefore, it is always important to consult with the municipal council before purchase to confirm that the urbanization is complete and that there are no pending charges.

Utilities

Within the level of urbanization we discussed, it is important to focus on the available services, which may include gas, electricity, potable water, sanitation (sewerage), and fiber optics.
In addition to considering them for future installation costs, it is crucial to thoroughly review telecommunications installations.

We must check that there are no nearby mobile phone or telecommunications network antennas, as well as electrical substations and high-voltage lines. This should be consulted with a measurement professional who has sophisticated measuring devices capable of detecting high and low-frequency waves that may affect the land.

At our office, we collaborate with one of Spain’s leading companies specializing in measurements. If you are interested in having a land measurement performed, you can contact us so we can help you assess which measurements will be necessary and advise you on the appropriate professional.

Regarding high frequencies (those emitted by mobile phone antennas, among others), prolonged exposure to waves produced by mobile phone antennas or telecommunications networks (radars) is known to negatively impact human health. Although limits are still being debated, and there are controversies between Spanish, European, and international maximum exposure regulations, we always recommend applying the precautionary principle and maintaining a prudent distance from phone antennas.

In addition to conducting an electromagnetic measurement study to check the incidence of waves on the land, the Spanish mobile antenna map can be consulted online for free, showing the exact location of mobile transmission antennas in Spain.

Regarding low frequencies (those emitted by power lines, among others), we must consider that the larger the power line, the greater the electric and magnetic field emitted. We should also stay away from electrical substations. The risk is similar whether they are overhead or underground, and their impact is significantly reduced with distance as well as depending on the time of day when the measurement is taken. In measurements taken near electrical wiring and high-voltage towers, we were able to verify that during the night the fields decrease significantly.

How to Determine if a Plot of Land is Buildable: Administrative Aspects

Cadastre

The Cadastre is an administrative register dependent on the state, where all rural, urban, or special-category real estate properties are recorded. This is where we must consult the classification and categorization governing our land to verify that it can indeed be developed.

Land classification distinguishes between three urban planning regimes: urban, developable, or undeveloped. The third type prevents building, usually due to protection contemplating its historical or landscape value. Within this classification, a specific categorization assigns specific purposes and uses to the future property.

Another necessary check is the square meters registered in the Cadastre which, as we mentioned in the topography section, we must verify on-site to ensure they correspond to the actual size of the plot. If fewer meters are observed than those registered by the Cadastre, we should check the municipal council’s plan and the deeds for the actual dimensions and boundaries of the land to address this conflict as soon as possible.

Regulations

To ensure obtaining a building permit, we move on to the most bureaucratic section of regulatory checks. The current regulations for the land are governed by the municipal urban planning ordinance.

Similarly, we must consult municipal plans, which detail future urban development projects. These are important to consider for anticipating potential impacts on a plot of land, such as re-urbanization that would entail a special assessment for each neighbor, as well as possible problems when purchasing land.

These regulations involve a set of construction parameters that will condition the design of our future home. Two of these factors are the permitted buildability and land occupancy, which limit both the maximum number of m² we can construct and the percentage of the plot area we can occupy. Furthermore, the regulations also govern boundaries with the street and neighbors, establishing the minimum distance between street-building and building-building.

Additionally, based on our studio’s experience in how to determine if a plot of land is buildable, we always recommend visiting the municipal technical officer. They may have information that is not published online, such as re-urbanization proposals or unapproved urban plans that could affect our land.

Building Permit and Taxes

A building permit is the municipal authorization to construct in a given municipality. Typically, an urbanization accepted by the municipal council guarantees that the council will cover the costs of repairs and maintenance of exterior and public spaces. In the case of private urbanizations that have not been accepted, residents must pay these costs. In the worst-case scenario, an unaccepted urbanization might not be managed by anyone, and therefore the municipal council would not grant building permits.

The building permit typically costs around 4-5% of the total Material Execution Budget (PEM) of our project and must be paid in full before construction begins. Additionally, the municipal council usually charges an extra tax, called the Tax on Constructions, Installations, and Works (ICIO). This is a state tax that each municipal council decides whether to apply, but it is generally applied to all new construction projects and is around 4% of the Material Execution Budget (PEM).

How to Determine if a Plot of Land is Buildable: Legal Aspects

Simple Note (Nota Simple)

The Nota Simple is the name given to the summary of information about a plot of land contained in the Property Registry, which must be requested to verify the legal status of the property.

Thanks to the Nota Simple, we can effectively identify the owner of the plot, as well as check for any potential encumbrances or easements associated with the land. Encumbrances or debts represent an additional economic cost added to the price of the land, as would be the case we recently described of a special assessment for street urbanization, for example.

Easements refer to services of another user that pass through our future plot, creating an easement situation to consider, whether from other neighbors or the municipal council itself. For example, a water pipe coming from another municipal or private plot, or a previous agreement with neighbors to run a cable.

Special Cases: Plots Resulting from a Subdivision

When learning how to determine if a plot of land is buildable, we will find that not everything follows exact formulas, as there are many special cases that we must review. One example of a special case is a plot resulting from the subdivision of a larger parcel, in which case we must add two extra checks.

Firstly, we must check if, after subdivision, the plot has sufficient surface area according to building regulations.

Secondly, confirm that services, especially sanitation, have been duplicated.