Fitting solar panels on a roof that is nearly due for replacement

With solar panels the conversation usually turns on orientation and yield. Dutch consumer authority Milieu Centraal supplies the rule of thumb: on a pitched roof it states that an angle of 20 to 50 degrees is usually most favourable, and that a roof facing south, west or east catches more sun than one facing north.

That question is only the second one. The first is structural: how old is the covering underneath, and what happens when it has to be replaced in a few years? The panels then have to come off and go back on, cabling and penetrations included — a cost that appears in no payback calculation.

On top of that, an array hides the roof surface beneath it. What you would simply see without panels during a roof inspection (€ 150-350) — a shifted tile, a weathered ridge, a defect starting at a detail — will sit underneath. Small defects you would have fixed early become defects you notice only once water comes in.

So the practical order is: have the condition of the roof established first, then plan panels. If the roof turns out to be due for replacement (€ 5,500-18,000) before long, do that first and lay the panels on the new surface. If it still has plenty of life, you can fit them with confidence. Every guide rate is in the price index.