Do I need to replace new tiles when installing solar photovoltaic panels on my roof

Yes, solar panels can be installed on a tile roof. A preferred technique is called an inset solar installation, or 'comp-out', which adds additional steps and costs but provides long-term durability and helps prevent damage to your home.

If you're planning on having the roof restored, it can be beneficial to have the work staged so cleaning and painting are done before the solar installation (including some spare tiles), and the ridges and hips are repointed afterwards so that work isn't disturbed by solar installers kicking tiles.

Terracotta tiles are kiln-fired and often aren't consistent in size and shape, so they don't always engage with the tile battens or each other very well. In contrast, solar panels are millimetre-perfect and will often show up sagging roofs, deviations in battens and other “organic” flaws tiles usually hide.

The risk for solar installers is that the tile under the bracket can be cracked if somebody rests too much body weight or steps on the racking. Cracked tiles can leak and are very hard to replace in this situation without totally disassembling the array.

Hardwood battens can spilt and move – as can rafters supporting them, which your solar frame is screwed to. So, a roof restorer who is looking for cracked tiles and otherwise focusing on repointing hips and ridges may not notice more general issues with the tile placement on the battens, and everything being perfectly straight and true.

In contrast, solar panels are millimetre-perfect and will often show up sagging roofs, deviations in battens and other “organic” flaws tiles usually hide. Hardwood battens can spilt and move – as can rafters supporting them, which your solar frame is screwed to.