Solar Panels 
Inverters 
CHARGE CONTROLLERS 
SOLAR PACKS 
Solar Equipment 
ENERGY STORAGE SOLUTIONS 
HEATING, COOLING AND HOT WATER 
ELECTRIC VEHICLE CHARGERS 
Solar Lighting Solutions 
Short answer: Suitability depends on more than roof size
For a roof to be considered suitable for solar panels, usable area, orientation and pitch, year-round shading, structural support, roof covering, electrical infrastructure, consumption profile and safe access must all be assessed together.
A map or satellite-image review is a useful starting point, but a site survey, structural assessment and electrical design are required to determine the final panel layout, estimate production and make an installation decision.
Is your roof suitable for solar panels? An 8-step pre-check
The points below will help you gather the right information before requesting a quotation. This check does not replace structural calculations prepared by an authorised engineer or the electrical project.
Determine the usable net area
The total roof area is not the same as the area available for panels. Chimneys, parapets, skylights, ventilation equipment, antennas, ridges and safe access routes restrict the layout. When taking measurements, record not only the square metres but also the divided geometry of the roof and the distances between obstacles.
Examine orientation and pitch together
The direction of the panel surface and its angle from the horizontal affect how solar irradiation reaches the panel plane. A south-facing surface is not the only option; east-west surfaces can also be used. The most suitable layout is determined by the roof's physical constraints and the morning-evening consumption pattern, as well as the annual production target.
Account for seasonal shading
Shadows from nearby buildings, trees, chimneys and technical equipment move throughout the day and across seasons. The European Commission Joint Research Centre's PVGIS tool can model the effect of the terrain horizon, but its approximately 90-metre terrain data cannot automatically capture shading from nearby objects. An on-site or detailed three-dimensional shading analysis is therefore important.
Have the supporting structure checked
The assessment is not limited to panel weight. The mounting structure, cable trays, maintenance loads and location-specific snow and wind effects must also be considered. The existing plans, the building's current condition and the connection points need to be examined by an authorised engineer.
Assess the roof covering and remaining service life
Tiles, trapezoidal sheet metal, sandwich panels, standing-seam roofs, membranes and concrete terraces require different fixing solutions. If there are leaks, corrosion, loose covering or a need for renovation in the near future, planning the roof improvement first can prevent the panels from having to be removed and reinstalled later.
Review the electrical infrastructure and equipment location
The main distribution board, meter, existing protective devices, earthing, phase configuration and cable route are part of the survey. The inverter requires an accessible and ventilated location that meets the manufacturer's installation conditions. Cable lengths and routing affect both safety and project cost.
Size the system according to consumption
The maximum number of panels that can fit on a roof is not always the right system size. Electricity bills for the last 12 months, monthly consumption, the hourly load profile where possible, contracted power and future loads such as a heat pump or electric vehicle should be assessed together. This enables a more realistic estimate of how much production can be consumed directly.
Plan access, safety and the approval process
Safe roof access for installation and maintenance teams, edge protection, walkways and emergency access should be addressed from the start of the design. Application and approval requirements for grid-connected projects may vary according to the type of facility; confirm the current process with the relevant distribution company and an authorised project team.
Which considerations stand out for each building type?
| Building type | Priority checks | Frequently overlooked issue |
|---|---|---|
| Detached house | Net roof surface, shading, existing electrical board, daytime consumption | Chimney and tree shadows lengthening with the seasons |
| Apartment building | Use of common areas, consumption model, roof access, technical and legal decision-making process | Assuming the total area is directly available to individual units |
| Factory or warehouse | Supporting structure, roof covering, fire and maintenance access, hourly load profile | Failure to coordinate the remaining life of the roof covering with the PV investment schedule |
| Flat concrete roof | Parapet shading, water drainage, structural loads, distance between rows | Wind effects caused by panel tilt and rows shading one another |
What is measured during a technical survey?
A qualified survey answers more than “how many panels will fit?” It collects the data needed to show whether the project is safe, feasible and aligned with consumption.
Physical and structural data
- Roof dimensions, pitch, orientations and level differences
- Chimneys, parapets, skylights, vents and other obstacles
- Covering type, fixing details and existing damage
- Supporting-structure documents and on-site observations
- Shading sources and safe access routes
Electrical and consumption data
- Electricity consumption and bills for the last 12 months
- Hourly, or at least daytime-night-time, load profile where possible
- Subscription, connection and contracted power information
- Main board, meter, earthing and cable route
- Suitable technical space for the inverter and other equipment
Pay attention when comparing quotations
Do not compare only the number of panels and total kWp. The written quotation should also clearly state the layout plan, production-estimate assumptions, shading and system losses, mounting solution, inverter design, protective equipment, project and approval scope, warranty terms and maintenance access.
Possible outcomes after the pre-check
Suitable for direct project design
The area, structure and electrical infrastructure appear suitable during the initial review. Engineering calculations and the approval process determine the final capacity.
Suitable after improvements
The project may become feasible following roof renovation, structural reinforcement, board modifications or a different panel layout.
An alternative solution is required
Heavy shading, inadequate load-bearing capacity or limited area may call for another roof surface, a solar carport or another suitable installation model.
Create a data-driven roadmap for your roof
CW Enerji states that it provides engineering, project design and distribution-company approval services based on information obtained during site surveys. Preparing roof photographs, the structural plans where available, consumption data for the last 12 months and electrical infrastructure information for the initial meeting helps speed up the assessment.
Frequently asked questions
Can solar panels be installed on a north-facing roof?
It may be technically possible, but expected production should be compared according to roof pitch, location, shading and other usable surfaces. “It can be installed” does not mean “it is an economical and efficient choice.” Different surfaces should be analysed by scenario using PVGIS and a detailed layout study.
Is a flat roof suitable for solar panels?
Flat roofs may be suitable and can offer flexibility in panel orientation and pitch. However, shading between rows, wind loads, weight distribution, drainage, roof waterproofing and maintenance corridors must be carefully designed.
Can solar panels be installed on the roof of an old building?
The age of the building alone does not determine the answer. The condition of the supporting structure, project documents, subsequent modifications, corrosion or damage and the remaining life of the roof covering must be examined. Reinforcement or roof renovation may need to be planned before the PV installation.
How many solar panels will fit on a roof?
The panel count cannot be determined simply by dividing the usable net area by the dimensions of the selected panel. Edge distances, shading, maintenance routes, fire and access requirements, the electrical design of panel strings and mounting connections alter the layout. The final number is determined after a scaled layout plan is prepared.
Is a satellite-image survey sufficient?
A satellite image provides a quick preliminary review of area and orientation. On-site verification is required for the condition of the roof covering, supporting members, nearby-object shading, measurement accuracy, the distribution board and the cable route.
If the roof is unsuitable, is solar energy no longer an option?
Not always. Subject to technical and regulatory suitability, different roof surfaces, a solar carport or other installation options may be considered. The alternative must be designed together with the consumption point and connection conditions.
Sources and further reading
- European Commission Joint Research Centre: PVGIS 5 user manual - use of pitch, orientation and horizon data in production estimates.
- European Commission Joint Research Centre: PVGIS data sources and calculation methods - model limitations, including shading from nearby objects.
- Republic of Türkiye Ministry of Environment, Urbanisation and Climate Change: Guide to Energy-Efficient Renovation of Public Buildings - rooftop PV pre-assessment and the need for structural analysis.
- TEDAŞ: Type specification for solar power facilities up to 50 kWe - supporting-system capacity checks and the structural-calculation approach.
- CW Enerji services - survey, engineering, project design and distribution-company approval services.
This content is intended for general information and preliminary decision support. Structural, electrical and administrative suitability must be verified for each project by authorised specialists and the relevant institutions.