Solar-Ready Roof Design in Ireland — South-Facing Pitch, No Shade, and the Right In-Roof Kit

Solar-ready roof design in Ireland: orient the roof south (or south-east/south-west), no shade from trees or chimneys, design the structure for the PV load. A 4 kWp system needs ~28 m² of south-facing roof. A 6 kWp system needs ~42 m². Plan the inverter location at design stage (typically in the utility room or the attic). In-roof PV (panels form the roof) is more expensive but architecturally cleaner; the panels replace the slate or tile. On-roof PV is cheaper and easier to retrofit; the panels sit on brackets above the slate or tile. SEAI grant support for solar PV varies; check current scheme. Most Irish self-builds on a south-facing pitched roof plan for 4–6 kWp.

TL;DR

• Solar-ready roof design in Ireland: orient the roof south (or south-east/south-west), no shade, design the structure for the PV load.

• A 4 kWp system needs ~28 m² of south-facing roof. A 6 kWp system needs ~42 m². Plan the inverter location at design stage.

• In-roof PV (panels form the roof) is more expensive but architecturally cleaner. On-roof PV is cheaper and easier to retrofit.

When this matters most

You're at design stage and want to add solar PV (now or later).

When this doesn't apply

The roof is on with no plan for PV.

Frequently asked questions

How much south-facing roof do I need for solar PV?

4 kWp needs ~28 m². 6 kWp needs ~42 m². A typical 150 m² house with a south-facing gable end has enough roof for a 4–6 kWp system.

What is in-roof solar PV?

PV panels that form the roof (replacing the slate or tile). More expensive than on-roof but architecturally cleaner. Common in new builds where the design integrates the PV.

Can I retrofit solar PV to my roof?

Yes. On-roof brackets fix the panels to the existing slate or tile. €9,000–€13,000 for a 6 kWp system (2026 prices). Check SEAI for current grants.

Sources

SEAI, Solar PV Grants 2026. https://www.seai.ie/grants/