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?

Yes I believe it is bad.
Daughter has a concrete roof on a Victorian house that replaced the slate tiles years ago.
It came up on her survey as a red flag that the concrete tiles may be too heavy for the house and should be replaced by slate again ASAP

I think you’d need to get a proper survey. Even if you replace the joists the tiles could be so much heavier that they cause problems with the structure of the rest of the house. And as others have said it may cause issues when you try to sell or remortgage- if you have a proper survey giving it the green light this might help (I’d still be very wary).

Why are you thinking of doing this? Do you need to replace the entire slate roof so you're thinking of changing to concrete? If the slate roof can be repaired/patched I would retain it.

Because its a fraction of the cost of slate

You can probably reuse most of the existing slates. We did with our 100 year old slate roof and it made the cost more reasonable. Keeping a slate roof will also improve the saleability of the house.

Concrete doesn’t last as long as or wear as well as slate. It’s a false economy.

It will outlive us.

Where are you getting your slate from?

It should, depends on the cost of reinforcing the existing rafters, or replacing them.
I’d try and reinforce them rather than replace.
What’s the cost comparison with the ‘fake slate’ things?

I have concrete tiles and they are fugly. The house creaks and we have cracks down the walls. I asked a roofer about them and he said that they are better than slate as they don’t lift up so much in windy weather - but that’s it. I’d replace them with slate in a heartbeat but we can’t afford it.

Do you actually need to replace your tiles?

But unless you have to reroof it's a false economy. Far better to keep slate and patch up.

Have you asked what proportion of the existing slates are salvageable? It may be you can just top them up.

@pigletjohn what do you think? current tiles not salvageable as nails have rusted. Surprised by the unanimous views given most my neighbours have concrete tiles.

We had to replace our slate roof a few years ago, I'm pretty sure they replaced with concrete. I had no idea about the joists needing replacing. Ours was the last house in a long terrace to have had to have the original slates replaced.

@deathbollywood Slate hooks will prevent lifting in the wind. The original slates should have been put in with copper nails which don't rust. Even a bodged repair with galvanized nails which will rust shouldn't damage the actual slate.

There are slate roofs close to a thousand years old. I think someone is trying to sell you the wrong thing, salvaged slates are worth considerably more than either new or concrete. Are they offering to take them away for free by any chance?

Our house had a slate roof originally, replaced by concrete in the 1960s. The tiles have weathered a lot but the worst thing is the moss. It is awful, the birds scratch it off and we get clumps everywhere.

A slate roof is more maintenance than a concrete tiled one , they are a lot more expensive ( as the op knows ). If your replacing the rafters at the same time then weight on the old rafters won’t be an issue. Concrete tiles are fine and will last 75 years plus. My mums house was built in the 30’s , ex council house and still has the original concrete rosemary’s on, in fact most of the estate does. They are worn now but after almost 90 years that’s to be expected.

If you want to keep the look of slate but don’t want the cost? Then maybe look at the fibre slate/ tiles as an option ?

Any house 1000 years old is not on the original roof. 🙄

Who is telling you you need to replace all the slates?

Why do you need new sLATES. .¿

they took ours off, put a membrane sheet thing on, then used all the original slates apart from a few. It was mainly new nails that were needed. Roofers said it’s good for another hundred years.

@deathbollywood Slate is so beautiful and natural.
Rain on blue slate roofs looks lovely.

Terracotta tiles and slate are aesthetically pleasing
Concrete tiles are much heavier and therefore can affect structural integrity if your house.

If you can afford it, go for slate.

Slate lasts around 400 million years (look it up)

Current practice round here is to use stainless nails (coastal area, formerly used bronze). They are centre-nailed and do not usually blow off even in storms.

You can get synthetic cement slates which are a reasonable match, though flat and smooth, and probably rescue enough of the original slates to restore on the front of the house.

Genuine slates are rather expensive.

Beware any roofer who offers to dispose of your old slates and stacks them carefully in his van. He is selling them.

I don't believe concrete tiles will outlast you unless you are fairly old and they will spoil the look of your house. If you are not in a polluted area they will hold moss. Blasting moss off shortens their life. They are much heavier than your roof was constructed to carry.

current tiles not salvageable as nails have rusted.
? Slate has nail holes pre-bored into them, so if the nails have rusted, you can easily pop out the old rusty nails and still reuse the slate with new stainless steel nails.

The original slates should have been put in with copper nails which don't rust.

Copper nails are the proper traditional way to do a slate roof. If you can, opt for copper over steel.

Yeah, I suspect your roofer is spinning you some shit.

The roofer knows he can sell them on sigh