• We invite you to join UKWorkshop.
    Members can turn off viewing Ads!

Efflorescence

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

julianf

Established Member
Joined
10 Nov 2017
Messages
879
Reaction score
330
Location
devon
As has been said above, the issue is, with absolute certainty, the cement render.

Replace it with lime and a lime (or other breathable) paint and the issue will magically go away.

The solution is simple, just not cheap.
 

Lard

Established Member
Joined
2 Feb 2014
Messages
101
Reaction score
67
Location
Abergavenny
I wouldn't say that there's no such thing as rising damp, but I think it's fair to say that it's very often mis-diagnosed (for more than one reason) and is a relatively unusual cause of unexpected damp patches (matron...).
Yep, I’d go along with that, no issue with that statement at all. 👍

I’ve had 40 yrs of construction experience, some of which as a building surveyor. I’ve also worked with some dubious characters who didn’t know enough ‘stuff’ to be given the ability to diagnose.

I don’t even mind opinions as long as they’re given as opinions and not packaged as fact.
 

Marischal Ellis

New member
Joined
20 Nov 2021
Messages
4
Reaction score
0
Location
Edinburgh
I agree with W2S re consideration of examinations. Many signs can show as rising damp so a wrong consideration.. Very often rising damp is not correct although the signs can look similar. Bad drain connection, block drains, blocked stacks, can be lumped together but often the wrong solution. Specialists are not necessarily that. A careful and thoughtful examination is essential. Overflowing WC can suggest rising damp if you keep looking at your feet. Just my tuppence worth. Best wishes to all....it is going to get better in time!
 

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
We'd better add rising damp to the list:

Sharpening:
Politics:
Religion;
Brexit:
Rising damp 😆🤣

Thanks for all the replies, i will dig out a bit of the plasterwork to confirm what it is and check the chimney and pot 👍
 

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
Make sure the pot's dry, otherwise it won't light....Just sayin.
I guess you can gently oven bake it or microwave it to expel moisture? A soggy spliff was never a problem i encountered 😆
 

MikeJhn

Grunkel
Joined
2 Sep 2014
Messages
4,327
Reaction score
213
Location
Kent mostly and France the rest
I'm not a builder, or surveyor, but re Mike's comment on rising damp: in my 1890 house: cellar, central brick supporting walls (ie far from any outside wall) strong efflorescence, even if brushed off many times, then chemical injection (by me, so not perfect) a couple of years ago now efflorescence almost all just on bottom course (below injection) so if rising damp is a fallacy, what's happening here? (nothing piled against wall, no paint or render.)
Hydraulic pressure from the external water table being higher than the basement, In the OP's situation everyone seems to be ignoring the fact that the external ground is half way up the wall, its not rocket science moisture is being held agains the wall by the earth, nothing to do with sand and cement render and gypsum plaster.

Our 400 year old flint stone house has lime mortar on the outside and render with gypsum plaster inside does not have a damp problem despite not having a DPC or DPM, the exception was when we first bought the external ground was half way up the back wall this was very damp and the floor had rotted, this was dug out to the bottom of the wall, new gutters installed with down pipes leading away from the building, we have not had a problem in the thirty odd years we have lived here.

And its not just my opinion that rising damp is a fallacy every construction professional body including my own agrees.

Note to @Lard including the RICS.
 
Last edited:

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
To be fair to all, its easier if you can actually see the place and the salts etc, but i have drawn a diagram to show layout and position of the efflorescence.

It may of course make things worse 😆
 

Attachments

Adam W.

Established Member
Joined
18 Apr 2021
Messages
1,913
Reaction score
1,975
Location
London, Jutland.
Hydraulic pressure from the external water table being higher than the basement, In the OP's situation everyone seems to be ignoring the fact that the external ground is half way up the wall, its not rocket science moisture is being held agains the wall by the earth, nothing to do with sand and cement render and gypsum plaster.

Our 400 year old flint stone house has lime mortar on the outside and render with gypsum plaster inside does not have a damp problem despite not having a DPC or DPM, the exception was when we first bought the external ground was half way up the back wall this was very damp and the floor had rotted, this was dug out to the bottom of the wall, new gutters installed with down pipes leading away from the building, we have not had a problem in the thirty odd years we have lived here.

And its not just my opinion that rising damp is a fallacy every construction professional body including my own agrees.

Note to @Lard including the RICS.
Well spotted, I didn't realise there was earth banked up against the rear wall, as it wasn't in the posts from baldkev that I read.

But the efforescence doesn't seem to be on that wall, so........

Anyway, I think most people call it rising damp because it seems to come from below floor level and is seen at the base of walls or in the floor. It's probably used as a generic term for a damp surface below waist height. Much like builders calling anything dry rot. I've even come across people calling DWB dry rot !!
 
Joined
16 Aug 2021
Messages
9
Reaction score
3
Location
West Wales
Getting back to the importance of using lime plaster on these walls; wherever the water is getting into the walls, sealing it in with a cement render will cause the wooden floor and ceiling joists etc to quietly rot away.
 

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
As previously said, its not confirmed it is cement render, i need to dig some out, but i suspect it probably is. A lot of general builders arent all that clued up on old building techniques and what is required. I have seen a few old properties with vinyl matt paints etc ( not breathable ) .

Thanks, kev
 

MikeJhn

Grunkel
Joined
2 Sep 2014
Messages
4,327
Reaction score
213
Location
Kent mostly and France the rest
From your diagram it would seem that the efflorescence is on a party wall, do you know what is on that wall in the neighbours house, bathroom, shower or kitchen, could be a leak from their plumbing.
 

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
Thats a good point..... if they have have a mirror of the customers house, it'll be a living room with chimney. Radiators are possible..... good shout, worth asking!
 

MikeJhn

Grunkel
Joined
2 Sep 2014
Messages
4,327
Reaction score
213
Location
Kent mostly and France the rest
If it is a living room in the neighbours house, is the party wall clad? chimney blocked off with no ventilation, is there a bathroom above? it may not show on the neighbours side, if you have a sensitive nose you may be able to smell the damp, I certainly could when I used to cary out surveys, I could also feel subsidence/angled floor in my feet, but that comes with fifty years of experience of inspecting heritage buildings.

Another point, is it a suspended/solid concrete floor, possible drainage damage under it.

As someone pointed out earlier, is the chimney in good repair, flashings, cowl on top, ventilated?
 
Last edited:

Lard

Established Member
Joined
2 Feb 2014
Messages
101
Reaction score
67
Location
Abergavenny
And its not just my opinion that rising damp is a fallacy every construction professional body including my own agrees.

Note to @Lard including the RICS.
Hmm, I’m all for constructive debate but not one that has the appearance of a rabbit hole 🤔

All I’ll say (and this is from professional experiences and personal opinion) is that I have more than a little contempt for certain damp-proof injection companies……

Re the RICS (and Mr Bonaface’s comment which I read in an article) my reply could not have been better written than the following (taken from the same article I had read)…..

Terry Brown, of GMW Architects, said: ‘It’s right to question the diagnostic skills of commercial damp proofing firms, but to state categorically there is no such thing as rising damp undermines a whole litany of rules of brickwork detailing I’ve adhered to all my professional life.‘Of course there is no reason why inherited conventional wisdom shouldn’t be challenged. [But] the challenge has to be scientific and not anecdotal.’

Anyway, I’ve more serious fish to fry as I’m still sat here waiting for my effin bandsaw to arrive and so I am mentally unable to spend time on any alternative and frivolous issues….😥

🙂 👍
 

baldkev

Established Member
Joined
29 Apr 2020
Messages
1,122
Reaction score
504
Location
devon
If it is a living room in the neighbours house, is the party wall clad? chimney blocked off with no ventilation, is there a bathroom above? it may not show on the neighbours side, if you have a sensitive nose you may be able to smell the damp,
The wall isnt clad on the customers side.... there should be a register plate over the woodburner..... im not sure on the bathroom question but when im out there next, I'll ask. The points in orange on the diagram are the only areas with the efflorescence happening

Thanks, kev
 

mikej460

Established Member
Joined
19 Jan 2019
Messages
1,092
Reaction score
740
Location
Daventry
Cement render on old building material just doesn't work, as pointed out above cement render doesn't allow the cob to breath and simply traps water which can only escape inwards. Only a lime render will work but the source of water ingress needs to be located. Cement render can crack, especially if it hasn't bonded to the walls and this will allow water in. I've pulled out weeds from render cracks before now. I agree with the above that it is rarely a rising damp problem that affects old buildings, it's often a combination of failed guttering or roof or roof flashing and incorrect materials. You can get the same problem where stone cottages have had their lime mortar raked out and replaced with rock hard modern mortar; a failed gutter, roof or flashing allows water into the stonework which leeches inside. If you line or tank the inside you are simply masking the problem.
 

Woody2Shoes

Impressive Member
Joined
5 Jan 2015
Messages
2,098
Reaction score
380
Location
Sussex UK
The wall isnt clad on the customers side.... there should be a register plate over the woodburner..... im not sure on the bathroom question but when im out there next, I'll ask. The points in orange on the diagram are the only areas with the efflorescence happening

Thanks, kev
Neither of your orange blobs appear to be anywhere near an external wall or a ground level change (?). They are both near to the chimney stack. I remain suspicious of the weatherproofing of the stack/roof above.
 

MikeJhn

Grunkel
Joined
2 Sep 2014
Messages
4,327
Reaction score
213
Location
Kent mostly and France the rest
@Lard I will take your Terry Brown and raise you Steven Boniface:

Stephen Boniface, former chairman of the construction arm of the Royal Institution of Chartered Surveyors (RICS), has told the institute’s 40,000 members that ‘true rising damp’ is a myth and chemically injected damp-proof courses (DPC) are ‘a complete waste of money’.

Additionally.


and lastly :The rising damp myth - whitworth

There is more evidence against than for the case of rising damp.
 
Top