A sensible question, and one I get asked on most surveys. You are about to let a team put a couple of hundred kilos of panels and metal on the roof that keeps your house dry. Does it damage the roof?
The honest answer is that it depends. If the roof is suitable and the system is fitted properly, no. If it is rushed, it can.
How a panel is fixed to a tiled roof
Nothing goes through the tiles. A roof hook is a bracket that slides under a tile and screws down into the rafter underneath. The hook is shaped so it comes out between the tiles, and the tile above is notched so it sits back down flat over the hook. Rails then fix to the hooks, and the panels clamp to the rails.
The membrane under the tiles, which is the layer that actually keeps water out, is not touched. The tiles sit back where they were. Water runs off the roof exactly as it did before.
Done properly, that is a fixing that will outlast the panels. A solar system should be good for 30 to 40 years, and by then most roofs are due some attention anyway.
Where the damage comes from
Rushing. Some companies install a whole system in a day. That is possible, but it leads to hurrying, and hurrying on a roof means tiles not notched properly, tiles not sat back down flat, hooks screwed into nothing solid, or cracked tiles left behind. Any of those can let water in, and you may not find out until the following winter.
We take as long as the job takes. Usually that is two or three days for a typical house, because we want the fixings right and the tiles back as they were. Nobody is rewarded for finishing early at our end.
What a good installer does with cracked tiles
Most roofs have a few cracked or slipped tiles that you cannot see from the ground. We find them because we are up there on the scaffolding with a clear view. Any tile that is cracked when we arrive, or gets damaged while we are working, we replace before we leave. It is easy to do while the scaffold is up and it means the roof under the panels is in better shape than the roof around them.
Roofs that are not suitable
Some roofs should not have panels on them. Very old or brittle tiles that crack when you look at them, rafters that are undersized or rotten, flat roofs with the wrong covering, and some slate roofs need a different approach. A proper survey looks at the roof structure, not just the orientation, and a good installer will tell you if there is a problem rather than fit panels and hope.
In roof systems, where the panels replace the tiles rather than sit on top, are another option on a new roof or a re-roof. We fit those too.
Questions to ask before you sign
- How are the panels fixed, and does the membrane get touched?
- How many days will the install take?
- What happens to cracked tiles you find?
- Who is on the roof? Your own team or a subcontracted crew?
- What is the workmanship guarantee? Ours is six years.
The answers will tell you a lot about how the job will go.
If you want a straight answer on your own house, we cover Cambridgeshire, Bedfordshire and Northamptonshire. We do a free survey and give you a clear written quote. Call 01480 400607 or read about our solar and battery installs.
Jason Pope
Owner, Selec Group