Advice on rerouting pipes and reducing noise

[TullioK]

Hello, I will be refurbishing a 1960s house and am considering what aspects of the plumbing might need changing, there's a couple of points in particular I would appreciate advice with. Some of the pipework looks like it might be 50 years old, other bits look like they were changed more recently. The central heating system has been updated and I don't think requires any work.

The house has a downstairs bathroom and a kitchen sink, and we would like to add a new bathroom upstairs. Currently the boiler is in the attached garage and the pipe from it runs the width of the house under the floor to the bathroom, then from here it goes up to the first floor and runs under the floor boards to the back of the house. Then back across the width of the house and down to the kitchen. This all seems unnecessary when it could just run under the floor straight to the kitchen from the boiler. The total length of pipe from the boiler to the kitchen is about 30 meters whereas I think it could be done in 10 meters by going under the house. Might there be a good reason why it has been done like this and why I shouldn't reroute the pipes under the house straight to the kitchen? There is varying depth in the space below the house of 2-4 feet, but enough room to get about and the drains and some wires already run in this space.

Now for noise. All the pipework is 15mm copper and it is incredibly noisy. I do not know how the previous owner wasn't driven mad; just turn the kitchen tap on and the whole house is wooshing thanks to the elaborate route the pipes take. I haven't measured the water pressure but it does seem reasonably high and I've heard high pressure can contribute to noisy pipes. Could the age of the pipes also contribute to them being noisy, perhaps they have some internal corrosion giving friction?

So any advice on rerouting and/or noise reduction would be highly appreciated.

Thanks in advance.

 

[MeldrewsMate]

You didn't mention the source of your hot water? Could it be you have a combi boiler in the garage? Could it be a hot water cylinder in the garage?
Whatever the truth, you seem to be suggesting that hot water has to come 30 metres (check the spelling) through the house to the kitchen, and this will cause a long delay, plus waste energy. It seems perfectly feasable to re-pipe directly from the garage hot water source to the kitchen, though there will be some digging as I doubt there is a suspended floor with a crawl space below in the garage.

As for the noise, it may be worth checking that any isolation valves to the noisy tap(s) are fully open, these can be a source of noise as can severely crushed pipes. Is the hot water at mains pressure? Could the source of the noise be one of the isolators from the combi boiler or unvented hot water cylinder? Is the street stopcock fully open? Is your house stopcock fully open? These are easy and quick things to check.

MM

 

[TullioK]

Thank you for your reply, MM. I knew I should have included more details in my post, just didn't want it to get too long! So in answer to your questions: yes there is a combi boiler in the garage, although it does not work at the moment. A boiler in the garage was new to me but I haven't yet thought of a reason to move it and it would be nice to not have the noise of it in the house.

You're also right that there isn't space below the garage, so I'd route the pipes from where they first enter beneath the floor of the house. I would draw up a diagram if you thought it would be useful, but it seems that you think there isn't a problem with going under the floor so I'm not sure it's necessary. I'd take the kitchen cold from the pipe feeding the boiler and the hot from the hot pipe coming back from the boiler, these are already under the floor just not going direct to the kitchen!

Both hot and cold pipes are noisy, the reason I mentioned the hot specifically is because of the bizarre route which it takes, but the cold follows it for two thirds of the way. To be honest I have not verified that there are not any valves or stopcocks partially closed, but so far I have only found the one stop cock where the mains enters the house on a 15mm pipe. There are no isolations valves on taps or toilet. The noise is definitely coming from pipework all around rather than from a specific source like a valve; would a closed valve transmit noise that is then emitted throughout the rest of the pipework?

I've also considered whether it's worth upgrading any of the 15mm pipework to 22mm.

Thanks again

 

[MeldrewsMate]

I've also considered whether it's worth upgrading any of the 15mm pipework to 22mm.

Beware of doing that without good reason, 22mm pipe has about double the cross sectional area of 15mm, so the (hot) water may take twice as long to get from its source (in the garage) to the tap outlets.