Replacing lead pipes in Victorian property

[JamesDunn]

We have just had a damp proof specialist in to repair our floor joists and plasterwork as well as installing a new DPC, and they recommended getting the main lead water pipes checked out as it is quite damp near where the pipes enter the house.

We have also had a water meter fitted by Thames Water which has a stop-tap and there is another stop-tap just inside our property boundary under a metal cover. This then connects to the lead pipe which is laid at a depth of about 40cm and runs a distance of about 75cm to the front wall of the house.

The lead pipe continues inside under the suspended timber floor until it gets to the concrete kitchen floor at the back of the house. At this point there is a isolating valve that can be closed with a screwdriver, and then the lead pipe disappears under the concrete floor. It finally reappears at the back of the kitchen where there is another stop-tap.

So what would be the best way to go about sorting these old pipes out?

I have read that new MDPE pipes should be buried at least 750mm, insulated and enclosed in a larger 100mm pipe, however given the distance from the water meter/external stop-tap to the inside this would seem a lot of work for such a short run! As previously mentioned, the lead pipe and external stop-tap are only 40cm deep.

Secondly, would it be acceptable to run the new pipe at the same depth (approx 40cm) into the house and then along the floor/beneath the floorboards in the kitchen and then above ground around the kitchen walls?

What sort of pipe should be used for the above ground section? Copper?

many thanks for any advice

James

 

[ree]

25mm MDPE plastic pipe from the external stop-tap to inside the house: Regs FWIW require a 750mm depth to protect against freezing. The supply pipe should be sleeved thro the house wall/foundation and insulated.

Personally, i would run a single length of 25mm MDPE pipe all the way from the external stop-tap to a convenient and accessible above floor point in, say the kitchen. Hang the 25mm MDPE from the joists.
At that kitchen point i would install an new isolating valve and transition to 22mm pushfit plastic eg. Speedfit or 22mm copper pipe. And run the new pipe at low level behind units etc to pick up and feed as it goes.

Abandon any inaccessible lead pipe and test the external stop-tap before starting any work.

The external stop-tap and all before it are the Utilities responsibility, all after it is your responsibility. If you can safely DIY connect to the new external stop tap then dont inform the Utility, just dig and connect.

If you have to branch off the MDPE before the kitchen isolator then come back here.

 

[TeaTime]

If you are replacing the pipework for the incoming mains, it must be at least 750mm deep and no more that 1350mm if you don't want to work outside of the normal requirements. I believe you can vary from this but you must contact your water undertaker first and wait for their response.

The Water Supply (Water Fittings) Regulations 1999

Part II
Section 5

any person who proposes to instal a water fitting in connection with any of the operations listed in the Table below–

(a)shall give notice to the water undertaker that he proposes to begin work; .
(b)shall not begin that work without the consent of that undertaker which shall not be withheld unreasonably; and .
(c)shall comply with any conditions to which the undertaker’s consent is subject.

TABLE
4................

(i)any water system laid outside a building and either less than 750mm or more than 1350mm below ground level.

You will need to duct the pipework as it enters you home and that duct will need to be insulated and sealed either end. Not sure if it needs to be sleeve for the full run from the undertakers service valve, but you will need to adequately sleeve it as it enters your property.

As for how the pipework is run in your property, that's up to you but I would have plastic under the floor boards and copper on show.

Hope this helps.

TT

 

[Hugh Jaleak]

The lead service was installed long before current regs were even thought of, so the method of installation of any existing service must be disregarded. Unless the house is massive, then 20mm MDPE is usually ample, run this at 750mm deep to the boundary, leaving a reasonable amount spare at the boundary to facilitate a connection.

Bed the new service in some sand to provide protection, and 'snake' the pipe slightly in the trench, don't lay it too taut. Provided it is ducted and insulated correctly where it enters the house, the pipe can be run underfloor to a suitable point as already suggested. Bring it up above floor level, fit stoptap and from there connect to existing pipework at a suitable position.

All the existing lead pipework will need to be disconnected at both ends, and abandoned once the new supply is live, no 'dead legs' are permissible.

 

[JamesDunn]

Thanks for the replies.

I phoned Thames Water yesterday to ask them if they would need to inspect the work and they said they wouldn't. In fact they didn't seem too bothered about any work that I would do within the bounds of the property!

Another question regarding the new pipe inside the house: is it ok to just lay the pipe on the ground below the timber floor or is recommended to secure it to the joists, or something else?

Also, as mentioned there are 4 places where the water mains can be isolated: at the water meter, the old (currently stuck) stop tap just inside the property boundary), the isolating valve before the kitchen, and the stop-tap under the kitchen sink.

Do I need so many stop-taps? Should I replace everything from the water meter to the sink stop-tap just with new pipes? Or I should I put a stop-tap under the stairs where the new MDPE pipe would connect to the new copper pipe above the floor?

many thanks

James

 

[TeaTime]

Fit a new stop tap once it enters your property.

Perhaps you had a few because the old ones seized, or couldn't be located???

Anyway, fit a new stopcock, at least you know it's new and not in dire need of maintenance.

Are you sure you conveyed to Thames Water that you will be running new incoming mains pipework from their service valve & that the depth of the pipe will be contrary to standards set out in the regs? I highly doubt they would show no interest if they understood you correctly.

They probably think you are replacing all the pipework in your property, not on the grounds as well.

 

[JamesDunn]

Fit a new stop tap once it enters your property.

Is this regulations or advice where practicable? The reason being is that the entry point is in the front room under the floorboards, which are up at the moment but will be secured and have underfloor insulation beneath them soon!

Are you sure you conveyed to Thames Water that you will be running new incoming mains pipework from their service valve & that the depth of the pipe will be contrary to standards set out in the regs? I highly doubt they would show no interest if they understood you correctly.

They probably think you are replacing all the pipework in your property, not on the grounds as well.

I will double check with them, thanks!

 

[Agile]

You should ideally have it in plastic from the street meter position.

Usually this would cost about £400 for them to make the connection. But many will do it for free under what they call the "lead replacement program" if you are removing all lead pipe from the property.

But they would usually insist that the entry to the house is brought up to current standards in relation to the depth.

I think that it is meant to be insulated where passing through the void under the floor.

Let us know how you get on.

Tony

 

[Hugh Jaleak]

I would be replacing any lead pipework left within the building, other than that, any existing copper (or plastic) pipework should be fine to leave in situ.

 

[TeaTime]

You only need one stopcock in your property.

And if you are re-running the pipework completely, choose an entry point that is best for you.

 

[JamesDunn]

After doing some digging in the front garden and finding a large root that has penetrated the house wall (!), i think it might be a good idea to get a specialist plumber in to look at this.

Any idea what it might cost for a new MDPE pipe to be laid and copper around the kitchen?

 

[ree]

As i indicated above, whoever does the job, there's no need to involve your Utility.

Isolate at the meter and make the new connection at the External stop-tap.
After releasing the in-situ lead connector use a, for example, 25mm x threaded 3/4" (or similar) MDPE adaptor to connect to the MDPE pipe.

How come the transition has moved from the kitchen to under the stairs?

FWIW: read my posts, and re-read them until you understand what you are being advised - I only speak for myself.
Some of your questions have already been answered.

If meeting a tree root is going to throw you off course then stop work, and immediately call a local plumber - a local one man band.

 

[JamesDunn]

Thanks ree for your detailed replies.

I can isolate at the meter, and I could make the new connection at the external stop tap, however after removing all I can of the tree root, it appears there is possibly another leak between the meter and the external stop-tap. I can't hear anything, but the ground is unusually wet around there, just as it is inside the front wall of the house.

I assume the tree roots damaged the lead pipes at both these points and now have a nice fresh water supply to grow some more!

Therefore I think it would be a good idea to replace the lead from the meter too. I have freed the external stop-tap but it doesn't isolate the supply, only reduce it so that part is useless.

Regarding having the rising main under the stairs as opposed to the kitchen; it's because the kitchen floor is solid (screed concrete) and the lead pipe is buried below it. I have access to the rest of the house because all the floorboards are up, including under the stairs.

Another thing that concerns me is the regs state that the water pipe should be 350mm from any other service pipes, as well as being 750mm underground! There's very little space in our front garden and the electricity, gas, and what appears to be an old gas pipe are very congested!

 

[ree]

Beyond making the MDPE connection, dont touch anything at or beyond the external stop-tap. When the meter was installed the Utility would have noted the communication pipe material and the depth and condition of the external stop-tap - all that is down to them.

Do as i suggested above, and then fill the trench and call out the Utility with a complaint ref. the inoperable stop-tap and the lead(?) communication pipe that seems to have a leak on it. Say nothing else. Chances are that they wont say much either but simply get on and replace the communication pipe and the external stop-tap.

Congested digs are par for the course in ground work - you just have to work very carefully, and do the best you can. If the gas or elec appear to be old and deteriorating then call them out too but on separate occasions. Dont do anything else until they've had their say.

But first, before any of the above, why not start posting some pics on here - given that you are working with dangerous supplies?

 

[JamesDunn]

Here's some pictures of where I've got to. The trench is almost at the required depth. You can see the electricity and gas pipes on the left, and what I think is an old disused gas pipe on the right (although for some reason the uploaded images have been rotated 90˚ anti-clockwise).

Service pipes outside

• JamesDunn
• 20 Mar 2015
• 1

Trench dug to about 75cm

Service pipes outside

• JamesDunn
• 20 Mar 2015
• 1

Trench dug to about 75cm

Couple more questions:

1) The total length from the water meter to the stop tap in the kitchen is 13m. What thickness MDPE pipe should I use? 25mm?

The MDPE section will only be 9m in a straight line, but more like 12-15m if I include bends, etc.

2) What thickness copper pipe should I use above the ground level around the kitchen?

The existing pipework after the stop tap is 15mm...

3) As far as I can tell, the MDPE pipe usually rises vertically within the first 600mm inside the property - can it rise more slowly through the ground inside the house (to minimise bends) as I do not want a stop tap at this location?

thanks
James