To my knowledge Cornish Houses have been build from early 50's to mid 60's. I find this architecture very interesting. Sadly it's a very poor quality build. But I'm surprised seeing so many of them around Tredegar and Ebbw Vale. Most poorly maintained but still standing strong. They are around for over 60 years and by the look of it they will last another 60 at least.
ddraig I remember the Cornish style houses in Cripps Ave being renovated if my memory serves me right I think they used supports to hold up the upper floor and removed concrete slaps and replaced with bricks .I canít remember the year this was done .
I think the problem with concrete houses is "concrete cancer" and the steel reinforcement inside the concrete expands and cracks the concrete. Once it happens it generally can't be stopped. They stand well provided they're very well maintained but they can't withstand the test of time if exposed to damp. Mortgage companies are nervous of them and they're usually cheaper to buy as a result.
I don't really know how long they might last. It's the classic piece of string phrase. I imagine by now some are in very poor condition.