As for the diameter: if your pressure and throughput are fine, there is no need to change things. Generally for drinking water you want as large as necessary, but as small as possible. This way the volume standing in the pipe is minimised and your water is the most fresh.
DIY
A place to discuss UK-centric DIY. No sheetrock or drywall.
Wikipedia details DIY as a form of anti-consumerism, ain't that something.
Useful places to learn things: (taking suggestions!)
A UK how-to and forum site. People tend to argue a bit, but a good place to get an idea.
Useful places to buy things:
https://www.toolstation.com https://www.screwfix.com/
Wide range of tools and fixings, shop format is like Argos. Always worth comparing prices between them. Don't sell lumber.
https://diy.com https://www.wickes.co.uk/
B&Q and Wickes. Often more expensive than TS/SF, but carries lumber and garden supplies too.
Wickes deals can bring prices in line with builders merchants.
Watch out with B&Q's website, as they do that thing like amazon, where people sell through them (often overpriced)
Amazing. Thank you
I did something similar years ago with a house built in the 30s, but notably lived in it quite a while first which influenced my decision. In the years leading up to the moment of convenience for plumbing access I had all sorts of issues with water shifting ground, your experience may be different.
Anyway, I fully gutted and remodeled because I was tired of constant surprise urgent issues. The pipes I discovered were a mashup of galvanized, copper, pex, and even a little lead on one drain.
I installed a full home run led system beside the existing plumbing and then cutover to that one day and regret nothing.
I was considering running a spare pipe system from boundary to kitchen (poking as far through through the wall as possible) and then "terminating" both sides in future but then its an added issue breaking the concrete out the front of the house to get through near the boundary stopcock...
I think ill see if i can cut a small section of the kitchen floor to where the straight run would end and reconsider my options from there when i see whats up
The joint from copper to steel might be a breeding ground for galvanic corrosion. I'd probably consider changing as much pipe as you can feasibly reach without tearing the rest of the house apart. If you can reach under/through, or make an access hole in the supporting wall, and then replace the pipe as far in as you can reach with modern PEM pipe (or whatever you use for buried pipe where you are from), from there to the boundary cock. Then you can leave the rest until you renovate other parts of the house, or until it becomes a problem. Plastic also gives you some galvanic isolation, which protects the rest of the galvanized piping. And then you have made sure you won't have to tear up your nice new floor down the road.
Unfortunately the joint is like a meter from the wall so i wouldn't be able to reach through. I was looking up plastic vs copper and as much as the flexibility half the cost wins, I've found some research articles about micro plastics with plastic piping potentially being a long term issue. Fortunately its a straight run so i can just poke a pipe through. I think ill see if i can cut a small section of kitchen flooring and see if i can find the end of the straight section and go from there. Might save me a lot of work
Was there ever municipal lead water pipes in your area? If so there might be old lead scale in the galvanized pipe
I have no idea tbh... hopefully i can get access through the kitchen today and see if replacement is straightforward! Valuable insight though!