Tanking solid wall mistakes

[Rmews]

I just bought a two story property with solid wall construction. I dampproofed the entire ground floor with tanking slurry two weeks ago only found out today it’s the worst thing you can do to a solid wall structure. Due to thermal expansion of bricks, cement tanking would crack which comprised the damp proofing also traps moisture in bricks! It could slowly erode the brick and mortar. I shot myself in the foot dramatically(((

Can I get away with it? I am intending to keep the property around 10-15 years.

Or should I spend more money to strip it out now.

My mind can’t take it if I have to do the stripping straight away.

Help!

Thank you

 

[Glenn586]

I reckon you’ve got a few years until the problems start to materialise.

 

[Rmews]

I reckon you’ve got a few years until the problems start to materialise.

Thank you for your comment! It seems like it’s more expensive to rip out the tanking in a few years than now. But I really don’t have much mental/time capacity to rip it out right now.

Should I just let it be and take my chances until I can’t wait any longer or just make it right at this moment before other stuff (insulation, electric wiring) put up on the wall?

 

[Cherryburn]

Ironically, if it was render you could at least have a chance if chipping it off. Slurry will be difficult to remove and require a lot of abrasives, quite possibly damaging the underlying brick in the process.

No one is going to tell you that it's okay to leave up, because we couldn't possibly guarantee that. Certainly without a lot more information. It's also not guaranteed that it will cause issues in 100% of cases, but then if there wasn't an existing issue with moisture then you probably wouldn't have gone to the trouble in the first place.

You mention insulating the walls, so it's worth bearing in mind that if you are committed to keeping the walls vapour open then you would need to use breathable insulation products, plaster and wall finish. This is also acting under the assumption that the outside face of the wall is also vapour open and hasn't been pointed or rendered with cement.

 

[Rmews]

Ironically, if it was render you could at least have a chance if chipping it off. Slurry will be difficult to remove and require a lot of abrasives, quite possibly damaging the underlying brick in the process.

No one is going to tell you that it's okay to leave up, because we couldn't possibly guarantee that. Certainly without a lot more information. It's also not guaranteed that it will cause issues in 100% of cases, but then if there wasn't an existing issue with moisture then you probably wouldn't have gone to the trouble in the first place.

You mention insulating the walls, so it's worth bearing in mind that if you are committed to keeping the walls vapour open then you would need to use breathable insulation products, plaster and wall finish. This is also acting under the assumption that the outside face of the wall is also vapour open and hasn't been pointed or rendered with cement.

The outside face of the wall is untreated.
The house is mid terraced, one party wall is neighbour’s kitchen, the other party wall is a meter room (not an active habitable room) I don’t think the kitchen of the neighbour is treated because I suspect they are causing the damp on this wall (therefore I thought tanking will keep the moisture to them). The front wall of the house is visible and accessible to me , the back wall is against somebody’s garden.

Damp level wasn’t bad bad, one guy even advise me to not damp proof it at all. The situation was: meter reading was high, but no visible water or patches. (worst wall was the party wall that is back to neighbour’s kitchen). But I was going to insulate and worried that even some damp will eat my insulation away so decided to dampproof.

would these info give you a better idea what should I do? I am desperate, help!

 

[aockenden]

My advice: don’t double down on your mistakes. You made a mistake and were paid in knowledge. Now take your knowledge and act on it.

 

[Lacan07]

The outside face of the wall is untreated.
The house is mid terraced, one party wall is neighbour’s kitchen, the other party wall is a meter room (not an active habitable room) I don’t think the kitchen of the neighbour is treated because I suspect they are causing the damp on this wall (therefore I thought tanking will keep the moisture to them). The front wall of the house is visible and accessible to me , the back wall is against somebody’s garden.

Damp level wasn’t bad bad, one guy even advise me to not damp proof it at all. The situation was: meter reading was high, but no visible water or patches. (worst wall was the party wall that is back to neighbour’s kitchen). But I was going to insulate and worried that even some damp will eat my insulation away so decided to dampproof.

would these info give you a better idea what should I do? I am desperate, help!

Meter readings won't tell you anything about damp walls, you've most likely been sold a pup which in this situation isn't so bad - no physical signs of damp on a wall is usually the sign to leave well alone and get on with your life rather than waste money on useless tanking.

Many old houses have been subjected to a renovation using 'modern' methods and materials and they cope just fine. The prime example of this are houses that have a slate DPC, when coupled with the fact that rising damp is incredibly rare (imho), they can usually take all kinds of modern punishment. A slate DPC won't usually fail and certainly not all at once. The biggest killer of an old house is usually high external ground, solid screed floors (that breaches the DPC), and faulty rainwater guttering or leaks.

So these are the questions to ask, how old is your house? Can you locate a slate DPC? How many of the walls in question are external facing? Are your ground floors solid or suspended.

I would leave be and get on with your renovations, if worse comes to worst you can always sell later down the line, but as I said above with no physical signs of any issues I think you've been played somewhat.

 

[Rmews]

Meter readings won't tell you anything about damp walls, you've most likely been sold a pup which in this situation isn't so bad - no physical signs of damp on a wall is usually the sign to leave well alone and get on with your life rather than waste money on useless tanking.

Many old houses have been subjected to a renovation using 'modern' methods and materials and they cope just fine. The prime example of this are houses that have a slate DPC, when coupled with the fact that rising damp is incredibly rare (imho), they can usually take all kinds of modern punishment. A slate DPC won't usually fail and certainly not all at once. The biggest killer of an old house is usually high external ground, solid screed floors (that breaches the DPC), and faulty rainwater guttering or leaks.

So these are the questions to ask, how old is your house? Can you locate a slate DPC? How many of the walls in question are external facing? Are your ground floors solid or suspended.

I would leave be and get on with your renovations, if worse comes to worst you can always sell later down the line, but as I said above with no physical signs of any issues I think you've been played somewhat.

The house is probably built between 1850-1900, no slate dpc I don’t think so. Two walls are external facing, one facing front which I can see and have access, the rear wall is back onto somebody’s garden. ( I worry their soil level is high)


Solid screed floor was put in 2024 by previous owner.

The tanking guy also internally injected DPC chemical solution.

Is this bad?


If there is no proper damp and I just wasted money on tanking would be my dream now ( not ideal but better than making damp worse)

 

[Cherryburn]

If they've gone from a suspended timber floor to a concrete floor then there is the potential for that to push more groundwater into the walls, it all depends on detailing really.

Injected "damp proofing" doesn't really do any damage beyond the holes that are drilled for it, I wouldn't worry about that.

 

[Lacan07]

The house is probably built between 1850-1900, no slate dpc I don’t think so. Two walls are external facing, one facing front which I can see and have access, the rear wall is back onto somebody’s garden. ( I worry their soil level is high)


Solid screed floor was put in 2024 by previous owner.

The tanking guy also internally injected DPC chemical solution.

Is this bad?


If there is no proper damp and I just wasted money on tanking would be my dream now ( not ideal but better than making damp worse)

As cherryburn says the liquid dpc won't do much harm, the concept / product is sound but the application less so due to the sometimes rather ragged nature of the mortar beds on the interior of old solid brick walls.

The recent installation of your screed floor is a bit of a dilemma however, but funnily enough it probably clarifies the situation because imho you're now at the point of no return. You'll never likely know how well they detailed the installation because what's the point digging it up. One would assume that they at the very least installed a dpm. At this point I would just complete your renovation as economically as you can, and if you experience any issues in say 4 or 5 years you can maybe think about moving on. But I think you'll be fine.

 

[mh12]

A slate DPC won't usually fail and certainly not all at once. The biggest killer of an old house is usually high external ground, solid screed floors (that breaches the DPC), and faulty rainwater guttering or leaks.

So these are the questions to ask, how old is your house? Can you locate a slate DPC? How many of the walls in question are external facing? Are your ground floors solid or suspended.

Lacan07 you've mentioned about solid screed breaching DPC.
I'm little confused if my property has DPC (slate type)- It's pre1900's Victorian property with solid. I suspect it doesn't but will look at junction between the blue engineering bricks and red facing brick.
If there is no slate DPC in place can we assume that DPC level is taken as junction between the blues an reds?
So essentially solid screed floor level needs to be below or at the top level of blue engineers in such properties? Is this correct?
Thanks

 

[Lacan07]

Lacan07 you've mentioned about solid screed breaching DPC.
I'm little confused if my property has DPC (slate type)- It's pre1900's Victorian property with solid. I suspect it doesn't but will look at junction between the blue engineering bricks and red facing brick.
If there is no slate DPC in place can we assume that DPC level is taken as junction between the blues an reds?
So essentially solid screed floor level needs to be below or at the top level of blue engineers in such properties? Is this correct?
Thanks

The problem is the level of any retro-fitted screed floor will always be the same level as the original suspended floor (for obvious reasons), and the DPC will always traditionally be sited lower than the floor level by a course or two (for obvious reasons).

 

[Cherryburn]

If you have blue engineering bricks near the bottom of your walls then that is your damp proof course.