Is replacing slate roof with concrete tiles always bad?

[deathbollywood]

I know aesthetically it's not great but we also plan to replace all the joists so I am hoping that sagging won't be an issue . Looking around at neighbouring similar houses I can see most now have concrete tiles. Also would I need to get building control sign off?

“I don't believe concrete tiles will outlast you unless you are fairly old”

this is simply not true.

here is a picture of our current roof tiles they are Marley and are 43 coming up to 44 years old , there is very little wear on them , they have weathered and are slightly rougher than new ones but there is no reason that they won’t last just as long again ( or longer). They is little to no maintenance on them and no nails to rust through as non of them are fixed down. I can easily walk around on them ( 12.5 stone).

im not saying they will last anywhere near as long as natural slate , but they will last as long as clay.

a well laid slate roof on the right property does look nice.

That was my thought too….the roofer is telling the OP porkies.

As others have said, they should be nailed on with copper nails and if not, even then can be reused. New waterproof membrane, new nails. A few extra slates for any broken ones and that should be all that's needed.

I'd get a second and third opinion.

Concrete tiles on a slate roof is a nightmare. They were flagged in our survey and the roof timers and joists were all bowed. We had to get a totally new roof - beams, rafters, the lot. Concrete tiles are twice the weight of slate and it’s unlikely the structure created to hold a roof built of natural slate will stand up to that additional weight without reinforcement. It may also bow your external walls and it’s a safety hazard. If you are in a conservation area or the property is listed, that’s an absolute no no.

My parents 150 year old cottage has Welsh slate tiles, they never age, in the 54 years of them living year many a roofer has offered to buy the slate from them and re roof for them, slate is the best there is.

you can get modern synthetic slates now....we used large size ones on our extension, did it ourselves, wasnt expensive.

My thoughts too. We reused most of our 100yr old slates, and the roofer bought in some reclaimed ones to match to replace any broken ones and extend the roof. The extra slates cost a few hundred quid, including the ones needed for a 12 x 10 foot flat roofed extension to be made a slate pitched roof. It looks perfect.

As a side note- it does depend on the slate. Ours are 100yr old, but most likely Welsh ( the best). Our roofer recently did a re-slate on a roof which had very recently been patched with some slate from elsewhere- I can't tremember offhand where but definitely not Indian which I think is supposed to be okay. He said this other stuff was awful, so brittle it cracked if you walked across it- he removed the stuff and replaced it when he reslated because those slates really weren't re-useable.

I suspect the roofer is going to sell your old slates and make a really good profit.
You will need to replace some of the slates but you should be able to source slates of the correct size from a reclamation yard for a reasonable cost.

It’s pan tiles that degrade so are not worth buying second hand and can often need replacing. They sort of flake off in layers.

The nails hold the slates to the roof so if the nails have totally rusted you’ll have slates slipping off the roof. Pan tiles are held on by a lip on the tile.
I can’t see how a rusted nail would damage a slate. Some dodgy roof repairs did cover slates with a bitumen type thing that did wreck the slates. It would be obvious if that had happened.