Environmentally-Friendly Rising Damp Solutions - Swipe Left, Or Swipe Right?

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jackthehat | 10:12 Tue 11th Aug 2020 | DIY
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Has anyone had any experience (domestically or professionally) with non-chemical/eco/environmentally-friendly Rising Damp solutions?

Historically RD solutions tended to be chemical injections or repairs to DPC where necessary but there seems to be a proliferation of the above type of system.
Are they a proper long-term solution to the problem of RD, or are they just a 'fad'?

I'd be grateful for any feedback on the above.


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I have some experience of this on previous house. I was told that only a properly installed DPC is effective all the other "solutions" are false economy.
Question Author
Thanks, TTT.
As new products and innovations appear on the housing-market all the time, I want to get passed the hype and marketing blurb and see if these systems do have any merit.
you have to grind out the morter/old DPC and slide in a new one, time consuming, laborious but not expensive if you do it yourself. The injected chemical stuff does have the correct properties but the application of it tends to dissipate it in such a way to make it ineffective in the long term.
A veritable can of worms here, Jack.
Back in the late 70s and early 80s, there was a definite fad for quasi-electrical systems to prevent "osmosis". (AKA rising damp.) I used to do a lot of hacking off and re-plastering after installation by "specialists."
Rentokil had a single wire system that supposedly prevented damp rising by somehow persuading the damp to stop at the wire barrier.
(No, it didn't last.)
McCoy-Hill had a "positive" system that needed two wires and a transformer connected to the mains. The idea being that this electrical barrier also prevented rising.
(No, that didn't last either.)
I've worked with chemical injection. Holes drilled... a solution of silicone in white spirit injected... then re-plastered.
There is some evidence that this, being an actual barrier, could be effective. Variations of this are still being used.

Then there were clay inserts stuffed into walls to wick out any moisture. Can work fine, but there's often remaining local spots where it is not effective.

In my humble opinion, there are two main solutions remaining.
1."Tanking". Either old-fashioned bitumen tank (several coats of painted-on bitumen) or a much more modern solution... such as "Vandex". Vandex is a cementitious painted or sprayed on coating. This can be very effective, especially underground.

2. Back-to-basics with lime plaster. I've done several old cob buildings, some of which had had various tanking attempts made unsuccessfully. (Not by me I should add.)
Hack off, and re-plaster with lime plaster, and finish with fine lime skim.
Believe me, it works well. You know the theory. The lime lets the walls breathe out any moisture, even if the external face is hard cement render.

I think I should stop there, at the risk that I'm sending you to sleep. ;o)
Question Author
Thanks, TB.

In discussions with a client, the 'Schrijver System' came up as a potential solution to a likely RD problem in their brick-built Victorian Terrace.
As they have a timber suspended floor they thought this system would fit the bill. It looks the part but, there again, the same could be said of many previous systems.

I think an injection-system would be favourite but Google has given my client ideas.... :o)
I haven't come across that system, but looking at their website, it does say they avoid harmful chemicals.
They keep coming up with these systems. No reason why they shouldn't do the job, but at a price I'll bet.
Brickbuilt Victorian is ideal for chemical injection if they're not too prissy about chemicals.
Silicone injection actually works best on brick.
Victorian most likely has a DPC (if any) of bitumen or slate.

I doubt that they want to go down the lime route, although it would do the job.
Injection looks the best bet.
(Although the first thing I would do is investigate condensation/ventilation etc.)

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