Underground condensate pipe

[Josephineyy]

Hi All,

I have been experiencing damp issues on an internal wall so my builder has been here today as part of the work.

While he was here he has pointed out that my mains gas combi boiler condensing pipe it below ground level and we cannot see the location which it drains too.

None of this seemed to be concerning until I mention that the wall being repaired for damp is directly behind this pipe and the room has had a failed floorboard joist previously.

The boiler was fitted in 2015 by BG who have given several home care service reports (most recent 2022) stating the system was safe etc.

Could this condensing pipe be the source of these damp issues?

 

[cross thread]

Be surprised it it’s causing damp at that level, the condensate looks like it’s going to a soak away it should be ( unless regs have changed) 18 inch from the house and into a limestone area

 

[Mr Chibs]

It's advisable not to have external render down to ground level, it should stop short, say 150mm (min) as it's possible to 'bridge' the DPC (Damp Proof Course) and can introduce damp.

I see there is an air vent on the chimney stack in the room, but there is no chimney on the roof, presume this is capped off, so there is nowhere for warm moisture laden air to vent to, it's common to put a ventilated chimney cap on the chimney pot, this maintains air flow.

What is the dark grey paint on the internal room photo?

I this a solid brick property or is it cavity walls? Do you know year of construction?
I'm guessing solid brick.

 

[Mike13]

could it be the pipe fixings letting damp through the external render?

 

[CBW]

Looks like penetrating damp as opposed to rising damp.

 

[Josephineyy]

Yes it’s solid brick.
The grey is some kind of primer that my builder it using to plaster over.
It’s fresh on today.

His worry is that the exit of the condensate pipe is not at all visible.

 

[CBW]

His worry is that the exit of the condensate pipe is not at all visible.

It’s as per @cross thread - it’s a soak away - I’m surprised your builder doesn’t know this.

 

[Josephineyy]

Thank you all. Any other possible causes for this damp?
Rising or penetrating?

 

[CBW]

Could be an issue with the chimney or the gutter to the side?

 

[RandomGrinch]

Thank you all. Any other possible causes for this damp?

A long shot, but I'm reminded of a recent thread - was there once a back boiler in that fireplace?
The poster had a leak in their C/H system traced back to pipes that were still in place, running to a previously removed back boiler.
I've only just removed connected, but obsolete back boiler pipes myself!
Does the pressure of your C/H system need to be regularly topped up?

There may also be an issue with inappropriate materials used with a solid wall. You appear to have a modern gypsum skim, over original plaster, and concrete render on the exterior.
These products are very good at keeping out water, but they also stop moisture escaping.
I had a similar issue with my solid (albeit stone) walls - I had a sopping wet wall, because moisture couldn't escape.
I took off the gypsum plaster; allowing the wall to breathe.

As has been said earlier, I doubt the issue would be from the condensate pipe alone - if you post your question as a damp issue in the building forum, you are likely to get some more ideas!

 

[mattylad]

Have you still got pot chimney pots on?
It was described to me that they are simply a bucket and rain will fall into it, fitting a cowl instead stopped my leaks.

 

[Andy165]

In cold weather, when on central heating or hot water, condensing boilers can produce up to 1 litre an hour condensate which is acidic and needs to be disposed of. If no drain nearby, then a soakaway full of limestone chippings. They should be checked and replenished yearly. They eventually go to mush because of the acidity of the condensate. The soakaway is recommended to be 500mm from the building. Yours is not visible. Maybe your downpipe is connected direct to a drain. Unlikely to be the cause of your internal problems.

 

[Madrab]

One question with that condensate would be, has that concrete base been laid after the condensate pipe was fitted?

If not then I fail to see how they've managed to get to a hidden drain gulley or a purpose fitted soakaway container filled with lime chips into that ground, or even just dug out the ground enough to get lime chips into that to ensure a correct soakaway, never mind that it isn't to standard being far enough away from the foundations, looks like they may have just cored a 35mm hole and then just stuck the pipe into the ground.



Is it the cause of your issue though, depends on what's under there and does it actually run/soak away