Weight of slate roof versus weight of cement tile roof replacement?

[N_Cook]

Or as tile and slate seems about the same weight per sq foot, what is the amount of overlap for slates and for tiles?

[tim....]

certainly against cement tiles.

I can't remember the prog but on one recent house buying program the buyer had to pay for a strengthen roof because the previous owner had replaced slate with concrete and the roof had stated to collapse.

tim

[dom]

There's plenty of deeply bowed roofs around here, where cheapskates have used concrete tiles to replace the original slate on older buildings.

[The Natural Philosopher]

ITYWF the original material was most likely thatch.

Only wood shingles are as light as thatch is.

Even pantiles will sag a roof designed for thatch, and they are about the second lightest I can think of.

[JTM]

We've recently replaced our slates (looked like cheap Spanish) with tiles more in keeping with the area (SW France) and the builder put another big purlin ? each side

[dennis]

I'm a cheap skate, I went into a roofing place today and scrounged enough slates to do a new roof.

It was a bird table though. 8-)

[The Medway Handyman]

Dunno. But around here there are hundreds of Victorian terraced houses. Those with slate roofs are fine, those with concrete tile all have a pronounced 'dip' in the ridge.

I believe its a good idea to reinforce the roof structure to avoid this.

[Bob Eager]

Our house (1903) was originally slate roofed. There used to be a roofing company right next door, and they re-did the whole lot at once before we moved, in with cement tiles.

Our surveyor picked this up and recommended reinforcement. Best idea would have been new purlins, but that was too major, so we ended up having supports for the purlins internally. That's been fine for 16 years.

[dom]

Nah - often happens in the middle of a terrace of slate roofs.

Former thatched buildings round here can usually be identified by the steeper roof pitch - around 50-55 degrees.

Usually these are done over with sagging red clay pantiles (though that may be due to roughly hewn roof timbers on buildings of that age).

On these pre-Victorian properties, usually with fairly random masonry, sagging roofs on pantiles look like character - though I'm not the person inside having to live inside with the roof leaks.

Sagging concrete tiles otoh, just look terrible - inappropriate to the building, glaring disjoint to neighbouring properties etc.

[N_Cook]

I hollared up to a roofer of 30 years scrabbling, reroofing in the same road today. He did not know a specific ratio but reckoned a cement tile roof is 3 times as heavy, for the same roof-scape. His unseen mate on the rear roof reckoned about the same

[george [dicegeorge]]

David Ireland's book 'How to rescue a House' says concrete are 4 times heavier than slate

[g]

[dennis]

You can get fibre cement "slates" that look OK, they probably don't weigh anymore than real slate and i doubt if anyone could spot them from the ground. They are cheaper too, i was given some that are about 60cm x 30cm and they retail for about 70p.