Where is this damp coming from? (with pics)

plumb1_2

I once went to a house that had a copper wire dpc (low voltage)buried into the mortar joint  a builder had drilled through it.
Ask me solder the wire back together, what a strange job that was.

FreeBear

plumb1_2 said: I once went to a house that had a copper wire dpc (low voltage)buried into the mortar joint  a builder had drilled through it.
Ask me solder the wire back together, what a strange job that was.

Ah. Reverse osmosis damp cure - A fine example of woo-woo science at work separating money and a mug by a charlatan.

Eldi_Dos

Apparently a few were installed in listed buildings, Del Boy must have spotted a opportunity while doing chandelier work.

Edit: 
Although in their defence pressurised telecomm cables of that era used a similar system to stop osmosis.During manufacture a lapping tape ( usually aluminium) was wrapped around the cable bundle before sheath was put on, this foil was made continuous at joint positions then to earth at exchange.The inducted voltage would then stop osmosis.
Most likely where they got idea to try as DPC.

diystarter7

Hi

When we lived in our biggest house a massive up-and-over terraced house in London, (i recall EA's referring to them as 'pre-1900's) about 40 years ago ie parents house, I was shocked to see no foundations. We had damp and woodworm - I'd pulled up the some of them to replace them and the wall sat on some type of rubb;e/hardcore - there was no dpc as far as i can recall in that house and we had it injected and it worked until my parents sold up about 10 years later so it can work.

Our current property's oldest is about mid 1950's and newest is mid 60's, none have encountered damp as yet. However, I've made sure all airbricks are clear and soil below DPC and water is not standing against walls or regularly splashing on to it.

Damp should be adressed as soon as you see it otherwise it costs more and not good for health

Thanks

silvercar

Assuming I have a dpc, how do I find it?

In the mean time, thanks to this thread I know I need to fill the hole between the render and the top brick line. What with?

Should I remove that tape? Can't see what it does. 

Is there anything else I should be doing, given that I am not lowering the whole drive?

JohnJ76

To find the DPC whether it be bitumen, slate or whatever they used, get a hammer/bolster and break out that section of cement infront of the wall. It may loosen some block paving but don't worry about that. 

Once you have broken it out dig down until you find a bed joint (horzontal between bricks) that has a dark band in it. It could look like gloopy bitumen (obvioulsy hard though) or slate (unlikely) or a roll of thick plastic like material.  That will be your DPC level.

If you don't want to lower  the drive you then want to go down ideally 150-200mm below the DPC if you find it, see the state of the ground and brickwork.  If it is all wet then i'd leave it open to dry out.  The pointing along that section isnt bad but there are a few obvious holes that need fixing - don't patch holes, just rake out the whole section and repoint it.   you can buy ready mixed (just add water) pointing but its pricey but you've only a small section to do so might not be too bad.  finished ground level should be 150mm below DPC to prevent splashback when it rains. 

Instead of the cement you want a french drain in front of the wall which is a bit of perforated pipe, laid holes down,  in a trench full of gravel (clean - no small bits) wrapped in a suitable membrane fabric to keep the gravel clean and roots out of the pipe. You could drain it into the flowerbed (which i hate near walls but thats personal preference).  Its easier to google a pic than describe in words. 

The tape looks next to useless, take it off and at least if gives you a better view of whats going on underneath. 

Is the wall north facing? judging by the moss on the roof and the green algae on the floor it could be a bit of a stale air spot. Looks like its in shadow, north facing walls are notorious for condensation as they are cold.  Once plaster starts to absorb moisture it can be like a magnet.  and gets worse to the point everyone things they have rising damp (which is actually not as common as people think and is often the catchall for all sorts of issues).  The fixings in the skirting are rusting and if it was me i'd just hack off the internal plaster and take that section of skirting off to see what was going on (especially condition of the sockets/wiring) but then when it comes to finding out the causes of problems i've learnt over the years its often easier to hit it straight on!    

silvercar

JohnJ76 said:

To find the DPC whether it be bitumen, slate or whatever they used, get a hammer/bolster and break out that section of cement infront of the wall. It may loosen some block paving but don't worry about that. 

Once you have broken it out dig down until you find a bed joint (horzontal between bricks) that has a dark band in it. It could look like gloopy bitumen (obvioulsy hard though) or slate (unlikely) or a roll of thick plastic like material.  That will be your DPC level.

If you don't want to lower  the drive you then want to go down ideally 150-200mm below the DPC if you find it, see the state of the ground and brickwork.  If it is all wet then i'd leave it open to dry out.  The pointing along that section isnt bad but there are a few obvious holes that need fixing - don't patch holes, just rake out the whole section and repoint it.   you can buy ready mixed (just add water) pointing but its pricey but you've only a small section to do so might not be too bad.  finished ground level should be 150mm below DPC to prevent splashback when it rains. 

Instead of the cement you want a french drain in front of the wall which is a bit of perforated pipe, laid holes down,  in a trench full of gravel (clean - no small bits) wrapped in a suitable membrane fabric to keep the gravel clean and roots out of the pipe. You could drain it into the flowerbed (which i hate near walls but thats personal preference).  Its easier to google a pic than describe in words. 

The tape looks next to useless, take it off and at least if gives you a better view of whats going on underneath. 

Is the wall north facing? judging by the moss on the roof and the green algae on the floor it could be a bit of a stale air spot. Looks like its in shadow, north facing walls are notorious for condensation as they are cold.  Once plaster starts to absorb moisture it can be like a magnet.  and gets worse to the point everyone things they have rising damp (which is actually not as common as people think and is often the catchall for all sorts of issues).  The fixings in the skirting are rusting and if it was me i'd just hack off the internal plaster and take that section of skirting off to see what was going on (especially condition of the sockets/wiring) but then when it comes to finding out the causes of problems i've learnt over the years its often easier to hit it straight on!    

Thank you for your detailed reply.

That section is west facing, but it is in a stale area. Next doors wall is just behind where I am standing to take the picture and the window section comes out a bit, so its a bit of a stale area. The brick driveway does slope away from the house, so I'm hoping that helps drainage. 

The electrician took the socket plate off and it was actually in a good condition inside, so I'm more concerned with the wall above that point. 

What would I use to bead between the render and the brick? Does that hole need drying out or can I fill it now?

silvercar

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

MikeJXE

The paving ism too high and the concrete fill around the edge is making it worse, west facing makes it worse still

Rain is bouncing off the paving up the wall, no question 

Doozergirl

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.