Would you use Roman Salt-Resistant Waterproof Lime Plaster - Rinzaffo Controspinta MGN?

[Bash_Bash]

Evening all.

I bumped into this product in another forum: https://www.coreconservation.co.uk/plaster/rinzaffo-mgn/

At almost £50 per 25kg bag it's pretty expensive; but it seems like it will do the trick for tanking, without harming the stonework underneath - if it's based upon the Roman solution and good enough for Venice as well as church crypts then it sounds promising. Thoughts? Thanks

 

[Glenn586]

What exactly are you trying to achieve with this application? It looks to me like it has contradictory properties which rings alarm bells. I have a problem area where I have used highly breathable wood fibre insulation and lime plaster and I don’t have a problem anymore. There again I was wanting to achieve the opposite of tanking and really encourage moisture disbursement. I’d be very wary about using this for an internal application.

 

[Bash_Bash]

It’s to tank a cellar. We’ve got a sump pump and plenty of ventilation, but the humidity is still high. Thanks for your thoughts on this.

 

[a twig]

Essentially using additives to create a hydraulic lime rather than high temperatures and claiming it offers better breathability as a result.

A vapour diffusion resistance (μ) of 15 isn’t horrendous but an NHL2 render from a decent supplier like St Astier will come out in the 12-15 range as well so I’m not convinced you would be seeing £30 worth of benefit per bag.

Handy generic reference table of typical mu values here for context

 

[Bash_Bash]

Essentially using additives to create a hydraulic lime rather than high temperatures and claiming it offers better breathability as a result.

A vapour diffusion resistance (μ) of 15 isn’t horrendous but an NHL2 render from a decent supplier like St Astier will come out in the 12-15 range as well so I’m not convinced you would be seeing £30 worth of benefit per bag.

Handy generic reference table of typical mu values here for context

View attachment 16217

As ever, this is why I love this group, thank you. Is NHL2 too soft to use in a damp cellar though?

 

[Stevers]

If the issue is humidity rather than salting then the application of a porous lime render might not address your concerns.

I used NHL 3.5 for my basement chimney breast, but am under no illusion that a fair amount of moisture isn't being 'breathed' into the room, despite it looking dry apart from in a couple of corners at the back of the fireplace opening that remain a little darker. Interestingly since removing the rest of the concrete screed from the Lias limestone floor and adding moderate heat from a radiator under the window, condensation on that large single glazed window has reduced to the point where a window vac is no longer needed each morning. The room is ventilated via a trickle vent on the (prevailing) windward elevation, that large original unmolested sash window and via vents through the back of some cased alcove cupboards each side of the fireplace that eventually exit to vents on the leeward side of the house via the ground floor cavity).

Laundry and in particular clothes drying takes place at the other end of our semi-basement in a room with another large original sash window. This does not seem to be a problem for any part of our basement - probably through maintaining adequate air changes in conjunction with some gentle warmth round the clock from our smart heating system. For background I should add that we are built into a hillside and our 'basement' is above ground at the back of the house. Moisture never ponds on the floor though we do get the occasional autumnal damp patch on those cool stone floors - something somewhat charmingly referred to as 'sweating'!

 

[samgo]

Be careful with Core Conservation, they may not be as knowledgeable or scientific as they make out.

They sell a “Magnetic DPC system” which as far as I can tell from my own research is complete BS.

Do your own research before engaging with them.

Heritage House | Aquapol and Core Conservation

A fraudulent damp proofing device sold as part of a sophisticated con

www.heritage-house.org

Magnetic DPC System - Working Principle - Core Conservation

The magnetic DPC system is an innovative, non-invasive damp proof course solution suitable for any old or listed building or heritage property.

www.coreconservation.co.uk

 

[Bash_Bash]

They’ve been trading since 2013, and on the surface look like a sound company. Again, thank you for this golden feeeback.

 

[Stevers]

There's a video from Core Conservation about the Heritage House basement damp treatment. Peter Ward was supposed to be working with them to demonstrate the success of the magnetic DPC system and it seems to have started off well with promises of periodic monitoring. Core Conservation claim that he has subsequently refused to engage with them, but he seems to have retained the magnetic DPC device. This was visible in a video where he appeared to be claiming that this very untidy and scruffy basement had responded well to only forced ventilation.