Cap off redundant drain pipe

[AdamD]

Had issues with rodents recently, cctv drain survey suggests a hole in the pipe, was quite clear from the camera. The area where it is is a redundant drain pipe and we need to excavate and cap it off. What sort of cost should I have in mind for my quotes? Ball park obviously.

[ProDave]

How hard depends on the type of ground to dig, depth, and type of pipe that needs capping (clay or pvc)?

 

But even of your visitor is getting into your drains, how is he getting into the house from there?

[Redbeard]

How deep do you have to dig? Assuming you maybe need to excavate the connection, take out a 'T' joint and replace a straight section the digging is probably the worst bit. Assuming the drain is circa 100mm you can get sleeves with jubilee clips to span the gap (or 2 smaller sleeves and an infill bit of pipe if it's a wider gap). Cross-posted with @ProDave.

Edited Friday at 16:45 by Redbeard

[AdamD]

15 minutes ago, ProDave said:

How hard depends on the type of ground to dig, depth, and type of pipe that needs capping (clay or pvc)?

 

But even of your visitor is getting into your drains, how is he getting into the house from there?

Concrete and likely earth below that. Not sure how far, maybe 0.5-1m.

It’s a clay pipe. 
 

Not sure but could be from the sewer, through the broken pipe and burrowing in. Hard to tell.

[AdamD]

15 minutes ago, Redbeard said:

How deep do you have to dig? Assuming you maybe need to excavate the connection, take out a 'T' joint and replace a straight section the digging is probably the worst bit. Assuming the drain is circa 100mm you can get sleeves with jubilee clips to span the gap (or 2 smaller sleeves and an infill bit of pipe if it's a wider gap). Cross-posted with @ProDave.

Not sure at this stage. No idea how to find out how deep it is. It’s like 18m from the manhole where we started with the cctv camera and uphill.

[AdamD]

2 hours ago, ProDave said:

How hard depends on the type of ground to dig, depth, and type of pipe that needs capping (clay or pvc)?

 

But even of your visitor is getting into your drains, how is he getting into the house from there?

The problem is we don’t know they are getting in that way, but we also don’t know they’re not. No other clear entry points and where the evidence was is commensurate with this bit of broken pipe. Crap like this is a shot in the dark in a way, feels like dead money but ultimately it’s a 90 year old house so dodgy clay pipe work feels sensible so it’s one of those do we risk them coming back by saving this cost or bite the bullet and say well that’s another avenue closed

 

any ball park cost estimates?  

[ProDave]

Seriously, a 90 year old house will be full of cracks and gaps that a mouse can get through.  They can get through the holes in an air brick.  You will NOT stop mice getting into that house.  Get some poison or your preferred type of trap and treat it as something you have to do living there.

 

My present house built to be air tight, is the first house I have lived in where so far the only mouse we have had in the building got in through an open window.  Otherwise they don't get in here.

[AdamD]

So the consensus is that capping off that broken pipe and relining the drain pipe isn’t worth it?

[markc]

7 minutes ago, AdamD said:

So the consensus is that capping off that broken pipe and relining the drain pipe isn’t worth it?

Really depends on whether you need the drain, if it’s all redundant, seal it up. You don’t need to excavate anything if the end is in your house and it’s not used, just pour some concrete in. If you cannot get to the end that’s in your place, dig as close as you can, find the pipe and break it, then backfill the hole.

[AdamD]

1 hour ago, markc said:

Really depends on whether you need the drain, if it’s all redundant, seal it up. You don’t need to excavate anything if the end is in your house and it’s not used, just pour some concrete in. If you cannot get to the end that’s in your place, dig as close as you can, find the pipe and break it, then backfill the hole.

We don’t really know what it is, it’s just past the main drain from the kitchen so must be an old connection maybe for the kitchen which was in a different orientation (our old water main came in near where it is so quite possible that there was something there) or an outside toilet maybe that used to be there - no idea on that. Next door has an outdoor toilet in the equivalent place so it’s not out of the question.

 

We can’t cap it off without excavating as it’s below a load of concrete!

 

spoke to a builder yesterday who thinks they’re not getting in that way and if in sewer would likely have seen them from toilet bowls, which is fair but without any proper investigation I don’t think he can be certain of that.

[AdamD]

On 21/11/2025 at 22:22, ProDave said:

Seriously, a 90 year old house will be full of cracks and gaps that a mouse can get through.  They can get through the holes in an air brick.  You will NOT stop mice getting into that house.  Get some poison or your preferred type of trap and treat it as something you have to do living there.

 

My present house built to be air tight, is the first house I have lived in where so far the only mouse we have had in the building got in through an open window.  Otherwise they don't get in here.

I get that but we can close off as many avenues as possible. I’ve got these to put over the air bricks, as an extra measure. 
https://amzn.eu/d/9sSNoRI

 

We’re soon to rip the kitchen out for a new one so hopefully can address any other obvious access points under the plinths and behind units etc