Can you replace a roof with solar panels on it?

If your roof needs replacing and solar panels are already fitted, the two jobs need planning together. The panels, mounting rails and roof fixings sit above the roof covering, so a roofer cannot simply strip and re-tile underneath them without dealing with the solar installation first.

Do the panels usually need to come off?

If the new roof covering is going underneath the panels or their fixings, the usual approach is to have the system safely disconnected, removed and stored while the roofing work is completed. A small repair away from the panel area may not need the same process, but that is a survey decision rather than something to assume from the ground.

The electrical disconnection and reconnection should be carried out by a suitably competent solar or electrical contractor. Your roofer should not guess which cables or isolators are safe to touch.

What needs checking before the roof is priced?

• The age and condition of the existing tiles, slates, membrane and battens
• How many panels there are and how the rails are fixed to the roof
• Where the cables, isolators and inverter are located
• Whether the roof needs a repair, partial renewal or a complete re-roof
• Who will remove, store and refit the panels
• Whether scaffold and access can be shared between the two contractors

What happens to the warranties?

There are normally several separate protections to keep track of: the roofer's workmanship guarantee, the roof-material manufacturer warranty, and the solar panel or inverter warranties. Ask who is responsible for the panels during removal and refitting, and make sure the roofing guarantee explains how the roof penetrations and flashing details are covered.

If the existing solar system is old, it may also be worth comparing the cost of removing and reinstalling it with the cost of upgrading it at the same time. That decision belongs with the solar contractor, but it is useful to raise it before the scaffold and roofing dates are fixed.

Repair or replace the whole roof?

Solar panels do not automatically mean the roof needs replacing. If the underlying roof is sound, a local repair may be the sensible option. If the tiles are failing, the felt is perished or the roof has reached the end of its serviceable life, removing the panels once and renewing the roof underneath may avoid paying for the same access twice.

Questions to ask before booking

• Will the roofer and solar contractor agree the sequence and dates together?
• Who disconnects and reconnects the system?
• Who is responsible if a panel, rail or cable is damaged during the work?
• Will the new roof use the existing fixing positions or need a new detail?
• Which guarantees remain in force after the panels are refitted?
• Will the price include scaffold, storage, removal and refitting, or are those separate?

Start with a roof survey

The safest way to price the job is to inspect the roof and the solar layout together, then agree the roofing and electrical scopes before anyone starts. That way you know whether you are paying for a repair, a full roof replacement, or a coordinated two-part project.