Is this a hole in my damp proof course?

[Geppili]

I wonder if anyone can help. I noticed that the wall of a bedroom which is painted dark navy stated producing chalky powder and around my DS bed I periodically see salty tide marks above his bed. The bed is pushed in a corner against two external walls. I investigated the wall below this point where there is a drain and am terrified to have found a hole in what I think is out Damp Proof course. Photo attached. The brick looks green and damp.

Can anyone recognise what might be going on here? Also who should I call to investigate?

Thank you so much!

Although there’s something going on with the wall, it looks like the drain has blocked if there’s that much stuff accumulating like that. Is it full of mud or debris?

Damp bricks below damp proof course is normal. However it is worth checking to ensure the course is not breached, often by debris or previous DIYers . It prevents damp rising so a hole is only a problem if rain is getting in.

Is the damp patch further up the wall or near the floor?

@Lonelycrab Thanks so much for your reply. The debris is on top of a drain grid. I will clear it and re photograph. I do worry that maybe there is a problem with the drain, but it has never backed up and I usually keep the grid clear.

@Worldgonecrazy Thanks so much for replying. Do you think I need a surveyor or builder?

@Worldgonecrazy The damp rises above this to the second floor box room. But along the ground floor I have noticed mould growing along the edges of our newish and v expensive oak engineered floor. I maybe wrong but I seem to associate seeing salt tide marks in box bedroom after heavy rain. Thanks again!

What age is the house? Is it stone built?

It looks like a hole in your pointing rather than the damp proof course. But...your pointing also looks to be cement?

If suspecting damp the best things to do are investigate gutters and drains etc are all in good working order first.

The ground level is supposed to be at least 15cm below the damp course level, so 2 layers of bricks. It looks like to the right of the drain, it’s basically at damp course height.
Also the pointing in the drain has deteriorated. You could probably just render that.
What is going into that drain? And can you post another couple of photos from a few feet away and also from round the corner?

@3partypics Thank you! It is a yellow brick built 1929-30 ex LA semi detached. I will check drains and gutters.

@C4tastrophe Thank you for your reply. I will take a clearer photo tomorrow and post it.

The drain gulley beside your wall, which your picture doesn't really show, has been cracked and leaking since 1940 or thereabouts. This is common. Several unsuccessful attempts have been made to patch up the damage but without digging out and replacing the broken gulley. Stand back and take a wider pic please

P.s.

The bricks you show are not London Yellow Stocks, which is a soft yellow brick. I think they are LBC Rustic Antique or something similar, a hard red brick.

@PigletInABlanketJohn Thank you so much for replying! Anymore advice/observations would be hugely welcome. I attach some more photos. The red brick is a sort of border at the bottom. I nearly fainted when you said this has probably been ongoing since 1940! 😂

This problem is very much like an elephant, in that once seen, it is easily recognised.

Assuming you live in or near a town or city, or a factory, dock, harbour, canal wharf or rail centre, there is a very good chance that the ground and house will have been shaken between 1939-45 by falling bombs.

Because the drains and gullies were made of fired clay, which is brittle and inflexible, it was quite usual for them to crack or break at about the point where they met the house.

The break is below ground level, so out of sight, and the water runs away without being noticed, turning the soil to mud and washing away lime mortar in old brickwork.

Attempted repairs usually include repointing the mortar, replacing loose bricks, and patching up the surface paving or concrete which cracks and settles into the mud. This often goes on for 70 or 80 years before somebody digs up the broken drain and replaces it. Sometimes holes are drilled in the wall and silicone injected, in a totally futile attempt to cure the water without repairing the leak. Annoyingly, the cost and effort of multiple futile repairs is greater than digging a hole and fitting a new part. It's not a complicated job, and pleasant enough in summer.

sometimes bright red worms, and wild tomato plants, are found around the break.

The pattern of house age, long-term damp, patched mortar and replacement bricks, in your pics is consistent with this diagnosis.

I may of course be mistaken. But I'll bet you 50p I'm not.

The damp on the second floor will not be rising from the drain fault. I expect it is a leak or blockage in the gutter or downpipe, especually if it coincides with the position of the pipe. Less often, a roof leak.

In sound, clean, exposed brickwork, "rising damp" can only get up about two courses.

@PigletInABlanketJohn Thank you do much for your amazingly detailed and generous reply! You are like a building whisperer!

That drain/gully can be replaced with a ‘sealed’ unit, where the down pipe goes into a plastic box which connects directly into the drain.
As mentioned you need to dig a reasonable sized hole to expose the drain work, but any builder can do this.
If this down pipe is heavy use, like the bath empties into it, and is frequently blocked by leaves, then it would over flow. And as pointed out by PJ, it’s in poor repair anyway.

Just a thought on the flooring issue - did you have a membrane underneath and rising around the edges? We had a floor installed and I recall this was part of the process.

Here are some pictures of gullies. The clay ones are very heavy and can snap a joint under their own weight. They typically break at the curve of the bend, and the socket joint.

Just to add my 2ps worth re piglet's posts- we had all our 100-yr-old ceramic drains relaid in plastic. The chaps who did it did indeed find several hairline cracks, just as mentioned, plus a blocked rainwater drain (from roots of a shrub, already removed as we saw it was too close to the drains) and also confirmed that the tarmac drive was draining water towards the wall as we suspected and they dealt with that too. Since it was done, the puddles that used to appear under the house's suspended floor in a few places when it rained, including the biggest one by where the tarmac drained, have gone. (We too had been told we needed injcted DPC and tanking etc, we already knew that was just bullcrap, so we ignored it.)
A bonus of the relaying was we got lots of access points put in for clearing drains, and easily accessible traps. Previously the old ceramic traps meant you couldn't get in anywhere to rod anything, or even put a camera down, and there were no acess points at all.

I have a drain gully like yours OP and I fashioned a 'lid' out of fine chicken wire to keep the leaves out & help it stay clear.