Are my concrete roof tiles OK (after washing / biocide)

[Allthegearnoidea]

I really debated having this done as I didn't want it to stand out like a sore thumb against other houses in the road, but several roofers recommended it even when they didn't offer the service themselves.  Not sure whether this has caused a problem, exposed a problem, or I'm just worrying unnecessarily!

 

It looks great from the ground, but up close the tiles look very eroded.  These tiles would be approx. 70 years old! 

 

Before:

 

After:

 

 

An original tile (I think?) - it says Marley Eternit on the rear.  The surface texture seems very different, so perhaps this isn't the original tile after all - or perhaps it's been eroded over the years?

 

 

 

I would be grateful for any experience!

 

Thank you

 

 

[Gus Potter]

1 hour ago, Allthegearnoidea said:

It looks great from the ground, but up close the tiles look very eroded.

I have similar on part of my roof. The tiles are on an age where they are likely going to be a bit more pourous. That in itself is not the end of the world. But a roof of this age (circa 1955) may have a bituminous underlay felt which may still be doing a little to catch wind driven water that comes in, or through the tiles due to porosity. Go up into the attic and see if you have felt or not.

 

The main thing for now is to check your roof ventilation in the attic. If you are skint just now then add some extra vents to get it as windy as possible. Then plan / save up for retiling of the roof in the next couple of years.