Drain 'sock' relining?

[MisterBoy]

Just had our main drain jetted, it was blocked under our drive and the Dynorod guy says he could feel roots.

He was saying the modern way to address this is to cut the roots out then feed a flexible resin-infused 'sock' all the ray through up into our courtyard, which is then pressurised and sets to give a continuous liner inside the old pipe.

What is this properly called? He couldn't give me any idea on likely cost and said they won't quote for it without me paying for a camera survey first, does anyone have any idea? Because my other option could be to get a mini-digger to dig a trench and re-lay a new pipe which would cost me (at a guess) £500 all in. But no idea which is actually a better approach.

 

[Hugh Jaleak]

They're not called Dyno Rob for nothing. Usual tactics of upselling work that probably isn't needed. I've never 'felt' roots when jetting, all you will get is an indication there is some form of obstruction in the pipe, only way of ascertaining what that might be is to do a CCTV survey.

Root cutting is easy enough, have you got any substantial trees near the drain? Lining is an option for damaged pipework, but without a CCTV survey it is impossible to say what the issue is. However, if you're confident you could relay the drain for £500 I'd ask them to quote for CCTV, (and if they know the length of the section to be lined, and confident its just roots and not collapsed, then I fail to see why they cannot quote!)

Personally, I'd tell them you'll wait and see, if the drain blocks again, get a second opinion. Or some rods, and unblock it yourself.

 

[MisterBoy]

Lots of trees so roots seems very likely but take your point. It unblocked easily enough and flowed freely afterwards so collapse sounds unlikely. Now I know I could give it a go next time, only used DR because we had a blockage so fairly urgent. I'm sure I could get other companies to quote if I can find some.

(DR quote £160 for CCTV though that would be all our drains not just this section, possibly worth doing with them or someone else to spot more issues in advance)

 

[Hugh Jaleak]

If they'll CCTV for £160 that doesn't seem too bad, ask for a copy of the DVD when they're done though! Also, if you can watch them do it, anything they pause on and/or note, ask what the issue is, (if not blindingly obvious!) Codes are used for drainage and defects found, no harm in preempting what they might try and tell (or sell!) you. Full liner would only be necessary is the whole section is cracked/in poor condition and/or in danger of collapse. Patches can be inserted to repair small sections of damage.

Anyone in the house using wipes, ensure these go in the bin and not down the WC!

 

[MisterBoy]

Can I ask what a 'patch' is? I'm picturing sliding a sleeve (a bit like having a medical stent!) inside an existing pipe?

The relevant section of pipe is dead straight 3-4m and has a nice manhole access at one end (about 2' underground) - at the other a vertical pipe is buried inside a wall but that part doesn't seem to be a problem. Is it feasible someone could do a DIY inspection and de-rooting on this short section alone? I actually have a set of drain rods but not sure what ends are available or if it's worth the hassle. A longer section I wouldn't even try!

 

[Hugh Jaleak]

Can I ask what a 'patch' is? I'm picturing sliding a sleeve (a bit like having a medical stent!) inside an existing pipe?

Yep, basically that. A 'sock' is inserted into the pipe long enough to cover the damaged section, placed in position and then installed to provide a structural repair.

Section as short as that, and at that sort of depth, providing no difficulty with access, I'd say more cost effective to replace rather than faff about with repairs. Root cutting tools arent available to my knowledge for DIY type rods, to be honest by the time you'd bought the professional gear to do it you'd be cheaper paying a contractor to do a root cut. I would get a CCTV survey done first and ascertain quite how bad the issue is. I suspect it may not be as bad as is being made out, and as I said above, virtually impossible to determine a root issue by jetting alone.

 

[MisterBoy]

Since we have (downstream from this section) another 20-30m of drain running down to our septic tank along a tree-lined drive, I reckon maybe getting a CCTV survey done is worthwhile. It slipped through the net when buying the place somehow.

Am I likely to find that every firm I approach demands THEY do their own CCTV even if I've had one done privately, do you think? I think DR offer it as a fixed-price thing, perhaps since it generates work

 

[Hugh Jaleak]

You only need one Survey, the camera wont lie. You've also paid for it, so ask for a copy of the survey and the report. Any future Contractor should be happy to work from these findings, no need to do another unless there has been a major change, (e.g. drain is blocked solid and you've a depression in the ground at around the same point!) The DR offer doesn't seem too bad, (if that's for the whole system and not just the 3-4 metre section that blocked!), just check there's no hidden clauses, e.g. they will expect to get any work identified off the back of it.

Out of interest, how old is the system? Older Salt Glazed drains are far more likely to suffer from root ingress than their modern Vitrified Clay and plastic alternatives.

 

[MisterBoy]

Thanks @Hugh Jaleak I'll look into their survey - not aware of anyone else local so far.

Background is that until 30 years ago, the house waste went straight into the river - previous owner was told otherwise but discovered this and installed a septic tank. I assume almost exactly 30 years ago. I can't speak for all the pipes but the manholes lead down to modern looking orange/black plastic chambers. I think I remember seeing modern orange drainage (100mm?) pipe leading into the septic tank.

Would 30 years count as modern still, has anything much changed since then? I would say we have a LOT of trees though:

The drain crosses the drive just near the power line, then runs down about as far as you can see. Those are old sycamores spaced about every 20 feet, the drain runs only a few feet inside the line of them so must've been cut through a lot of roots when first installed!

 

[Ian H]

You could always try your insurance if you think there will be more roots in the longer section.

If your insurance appointed contractor unlocked and CCTV’d and found no faults, you would make no claim and incur no cost as far as I understand.

If your 4mtr section was 100mm pipe I would guess it would cost around £350 to line it. That’s a £300 initial cost to set up, includes the first 3mtrs of liner, then £55/mtr after that. That what our place used to charge when the prices were on our job sheets.

 

[Ian H]

Bit about lining here:
https://www.diynot.com/diy/threads/drainage-engineers-chat-lining-drains.484605/

 

[MisterBoy]

Bit about lining here:
https://www.diynot.com/diy/threads/drainage-engineers-chat-lining-drains.484605/

Very interesting. Thanks

 

[Hugh Jaleak]

Plastic is probably less likely to suffer major root ingress issues, less joints, and less chance of it fracturing with slight ground movement. Vitrified clay is laid in shorter lengths, (so more joints), but the modern stuff is flexibly jointed, and again, less likely to allow root penetration.

Plastic drainage was well established 30 years ago, so is very likely to have been used. CCTV survey may prove interesting actually, as things may not be as bad as you fear.

I would however, keep the Septic Tank under your hat, if the outfall goes directly into or near the river, the EA may well want it upgrading to a Package Treatment Plant....

 

[MisterBoy]

Luckily the tank has a proper drainage field but yes I think I read septic tanks no longer meet regs in new installs, so it would need a modern treatment plant if and when it has to be replaced(?)

 

[lostinthelight]

I installed some septic systems in the first half of the 1970's and used plastic..