Drain Pipe relining /no drill sewer pipe replacement

[user1479460899]

I was wondering if anybody has had any experiences with relining pipes /sewer pipes please? Did it work and have you had any problems with it? How long ago did you get it done?

We've bought a victorian terrace in north London and the CCTV survey of the sewer pipes showed hair line crakes in some of the victorian clay pipes. As we have a problem with a some movement in a nearby wall and as all pipes are of the same age, we decided to get all pipes relined. This unfortunately means we are immediately talking serious money.

I've got quotes from various companies, but neither of them is particularly convincing. The prices are varying by approx. 2K. The warranty they give varies from 5 to 15 years. The problem I have is, that no company is clearly saying which liner they are going to use, so that I could read up about this particular manufacturer online. Or the company has only be in business for 2 years, so my 10 year warranty may not mean much if they won’t be around this long.

… There are lots of things that need doing around the house and the pipes will basically eat our whole renovation budget, so I would love to make sure I’m getting this right and I won't need to look at the pipes for the next 10 years again...

Any experiences are truly appreciated.

[PigletJohn]

no, but if it's a Victorian property in London, it is quite normal to find that movement over the years has actually broken the pipes, not just hairline cracks.

It usually occurs at the bend where the soil pipe turns from vertical to horizontal, a yard or two below ground level, and at the bend in the yard gullies where you see bathroom and kitchen waste pipes emptying into a visible, usually dark grown glazed clay, drain with an iron grille.

Leaking gullies are easier to spot, as the ground around them will have sunk, and several attempts will have been made to fill or conceal the hole, usually involving patched and cracked concrete (which sounds hollow when hit) or tiny brick surrounds. There might also be rats.

If you have these common breaks, then I think you will sooner or later have to get them dug out and replaced. They are usually neglected because people don't like the effort of digging holes. If you consult your neighbours with similar homes, some of them will know what was done to their houses, as may wrinkled old local builders.

The cause is settlement of the house into soft London clay, encouraged by skimpy Victorian foundations, and rippling of the ground from nearby explosions in the 1939/45 unpleasantness.

[johnd2]

You could always take out Thames water plumbing insurance at 6 pounds for the first year. Then next year tell them you think the drains are leaking.
In seriousness, unless they're 4 feet under 6 inches of concrete, I can't imagine it would be a problem to dig and relay them. Our builders dug a 1m trench all round the extension in a couple of days, and relaid the drains to the man hole in plastic in a separate hole. I can't see how it would be so expensive to reline?

[BillyJoel]

If the pipes run under the house, then the least intrusive way of fixing it is to reline. Same for if the pipes are outside. whether it is worth it depends on how deep the pipes are and how much garden, concrete, garage, conservatory etc would be disturbed by doing the dig. It is quite a complicated setup and so the cost will be dear. It also becomes dear and more complex if there are many side pipes joining the main pipe, as the location needs to be marked and then they need to be drilled through afterwards to recreate the hole.
The lining is expensive but quick and does not leave a mess, assuming they can set up close by.
I have seen it done well in the past, both in a commercial premise and in public sewers.

[user1479460899]

PigletJohn thanks a lot, it is great to read what to watch out for. Unfortunately, the gullies are hidden underneath some decking so I don't quite know how the ground around looks. Fortunately, we don't have rats (yet), but I agree that we need to do something about it. However, as at least one pipe runs underneath the house, and the pipes in the front of the property are under concrete, it's not feasible to dig them up. There is just one part on the back, where digging is an option. I'm just wondering, if this would really be so smart, if the ground around is totally saturated with water, and the wall adjoining the pipes/gully is showing downward and outward movement already. ... I'm a bit worried that once they start digging, the wall may continue it's current trend and buckle out further, so to speak.

[user1479460899]

johnd2, thanks for sharing the experience from your builders. That's helpful to know. And may be an option at the back of the property, if we decide to sacrifise the decking. It looks indeed like it may be more affordable. Thanks a lot I will look into it.

[user1479460899]

BillyJoel thanks a lot for your thoughts as well. You are right that the comparatively non-intrusiveness of it is appealing. Especially helpful is your remark about the side pipes. I was wondering how they would get it water tight if there is a side pipe coming of. It sounds more reassuring if they drill the hole after the liner is installed. This part is very close to our problem wall. So the majority of companies suggested to lay some new pipe here. However, as mentioned above, if the ground is so saturated by years of water leaking into it, I'm not sure if the digging up of the ground right next to the wall will mean it loses even more stability and all of a sudden I will have another problem to deal with. What do you think, am I just seeing problems where there aren’t any?

[PigletJohn]

London terraces more often have a common sewer running along behind the houses, that comes out to the road at end of terrace, rather than running pipes from front to back under the house.

Sometimes people foolishly build extensions on top of them.

[PigletJohn]

p.s.

digging up concrete is tiresome, but far from impossible. With a big saw and a breaker they'll be through it before the tea's ready.

[BillyJoel]

I think the side pipe holes are quite neat and tight to the edge of the main pipe., so water should not leak behind the lining. From memory, they insert a double membrane with the plastic-to-be between, then inflate the middle to push it into the pipe wall, then somehow make the plastic set. Can't remember what triggers the reaction to make it set. But basically it pushes the liner against the pipe side so there should be no gap behind. The lining also becomes rigid and is like putting a new plastic pipe inside the existing damaged pipe, so it provides support to keep the collapsed section back. At least that is how they did it and how the ones I saw worked. You might want to check the description you have been handed and see if it is doing what I say it will.
I would be very wary of excavating next to a wall that is already failing. Not if you value the wall and anything it is holding up or back. If you do excavate, make sure your builder has insurance as sometimes your house insurance is invalid while you have building works done.

[BillyJoel]

Just rereading your original post, you say all the pipes have hairline cracks. Hairline is not so bad and water won't be pouring out of the pipe. The problems lie ahead if the cracks open and soil seeps through and is washed down the pipes. You then have a big hole around a pipe and that is when walls and ground above start moving into the void that has been created. Also if the pipe starts to open the cracks, you lose the pipe strength, volume, and things you flush down the loo and sink get caught on the edges of pipe and build up into blockages (a few babywipes, some fat binding it, some poo...) Doomsday scenario here, but these are possible eventualities. How long do you plan on living here?

[Pestilence13610]

Had our sewerage pipes lined today, paid for by the insurance.
We found a well in the garden in the summer and contacted insurance. They checked sewers as part of their survey, found a couple of small cracks unrelated to well collapse and arranged for it to be mended. Job took about 3 hours, mainly double checking with the camera and waiting for plastic to cure.