Damp along party wall, which plaster material to use??

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liam546

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I have recently bought a semi detached Victorian Property which is constructed from 9inch Solid Brick. I am suffering damp patches all along the party wall. There is a cellar beneath the property but next door have had there’s filled in some 10 years ago, they have also had their side of the party wall re rendered in what I suspect is either sand & cement or gypsum plaster. Both downpipes, front and back of the properties go into the main drains. The party wall on my side also has what I believe is gypsum plaster although I’m not 100% sure. I have removed 1 meter of this plaster to let the wall dry out whilst I decide the best course of action. I have asked next door what they have along that wall and there is barely anything, and no signs of damp there side although I suspect this is being hidden from the new render. I mentioned that the construction of my property is 9 inch solid brick, this is true with the exception of the party wall (where the damp is). The party wall seems to be constructed of a type of rubble, with bits of stone in it, but the cellar wall beneath is again different, this is more like a solid stone, but as soon as it reaches the ground level it changes to this type of earth, rubble with stones in it. (Ive uploaded a pic of cellar wall, and the damp of the party wall before i removed the plaster. I will upload pic of rubble wall asap)
I have read lots about chemical injections and the use of sand and cement with water proofer and I feel i should avoid this as this method would be just sealing in more moister damaging the fabric of the wall and not allowing it to breathe. I have read that the solution may be a lime based render with use of breathable paints which will allow the wall to breathe. However I am worried that I would use the lime render or an alternative that I’ve read about called limelite renovating plaster, redecorate with breathable paints but then still get the damp which would be a lot of effort and money wasted.

Any expert advice would be much appreciated
Cellar Wall.jpg Damp On Plaster.jpg
 
I would hack off min of 1.2 m high or even 1.5m high.also hack off 1m return at end of walls.Use heater or dehumidifier to dry it out. Limelight is fine to use.ascertain. The cause...
 
Nice post Liam, you have obviously done a bit of research, difficult one realy next door having the basement filled in is probably the problem you need someone competent to have a look at it maybe not a damp proof company, where are you based.
 
Thank you for your replies, madmonk can I ask what you mean by Sbr slurry?

Lucius - thank you, I have done lots of reading. I have today cleared all vegetation from around window bays. I have also noted that there are two air bricks which are not blocked to the rear of the property. The air flow can then go through the first room and then through two more access holes into the cellar. The airflow can then exit via the coal shutes and drains that enter the cellar. I'm quite happy with the airflow under the wooden suspended floor and happy too with the down pipes that go into main drains. The wall with damp on I think maybe known as a 'clunge' wall which was used in my area but needs to breathe. I'm thinking it may have been the gypsum plaster that was used on top that was attracting moisture from the clunge wall and drawing condensation from in the room too. Or it could be to do with next door filling in their cellar as you say. Although the cellar is only on the front of the house and therefore I would have thought it would only affect that part of the party wall. However this is not the case as I have damp along the length of the whole party wall, back room and front. I live in Royston, Herts and would appreciate any extra ideas as to why the damp is/was there. U can't see damp now as its removed and bricks drying out. I have removed plaster to 1.2 meter as suggested
 
Thank you for your replies, madmonk can I ask what you mean by Sbr slurry?

Lucius - thank you, I have done lots of reading. I have today cleared all vegetation from around window bays. I have also noted that there are two air bricks which are not blocked to the rear of the property. The air flow can then go through the first room and then through two more access holes into the cellar. The airflow can then exit via the coal shutes and drains that enter the cellar. I'm quite happy with the airflow under the wooden suspended floor and happy too with the down pipes that go into main drains. The wall with damp on I think maybe known as a 'clunge' wall which was used in my area but needs to breathe. I'm thinking it may have been the gypsum plaster that was used on top that was attracting moisture from the clunge wall and drawing condensation from in the room too. Or it could be to do with next door filling in their cellar as you say. Although the cellar is only on the front of the house and therefore I would have thought it would only affect that part of the party wall. However this is not the case as I have damp along the length of the whole party wall, back room and front. I live in Royston, Herts and would appreciate any extra ideas as to why the damp is/was there. U can't see damp now as its removed and bricks drying out. I have removed plaster to 1.2 meter as suggested

hahahah clunge
 
At least I think it's a clunch wall, can any clarify what type of wall this is? I'm quite certain it's clunch in the cellar, but then the material changes to more earthy rubble with smaller bits of stone and brick. If I could identify what this wall is I might have a chance of rectifying the damp. At least that's my thinking.
 
My property is a semi two story and having looked at what clinker bricks are I'm quite sure the wall isn't made of these. It's much more earth with smaller bits of flint, stone and brick mixed in. It's quite soft and be chiseled away with ease. Any other suggestions as to what this is would be much appreciate? ........perhaps it is just another variation of a clunch wall.
 
My property is a semi two story and having looked at what clinker bricks are I'm quite sure the wall isn't made of these. It's much more earth with smaller bits of flint, stone and brick mixed in. It's quite soft and be chiseled away with ease. Any other suggestions as to what this is would be much appreciate? ........perhaps it is just another variation of a clunch wall.
I would go for lime plastering on these walls, the are a night mare, too hot the swell, too cold the fall apart, the need to be protected from the elements otherwise the cold can cause it to fall apart through freezing, the allow water to run through like small streams. If the neighbours have da,proofed their side all damp will come to you
 
Same as Jhon I would go for pure limed in this situation, putty or NHL, ime not far from you.
 
John - I have looked into Bunglaroosh. these pics were taken from my iPhone. The wall is earthy with broken brick, stone and flint so it is quite soft and dry in places where you can just loosely chip away and in other places its quite hard. I've looked into bungaroosh and it does have some visual similarities but I'm not convinced this is what it is as there are less stones in my wall and it seems that bunglaroosh was mostly used in the Brighton area between 1750 and 1850. My house is a Victorian around 1890 and I'm 3 hrs from Brighton. Thank you though, any other suggestions?
 
Bunglaroosh was used all over the country I believe, we done a house in London se1 which was constructed with waste from batter sea power station, old pottery, bricks ,clay pipes, old plates ,cups etc, I still say lime for yours is the best option, it is expensive though, there are some lime experts on here...
 
Ok - I'm looking at limelite as this from what I've read is less expensive than using traditional lime but is easier to use but still retains the properties I need to allow the wall to breathe. I am however concerned about how it will affix to this type of earthy rubble wall. Mad monk suggested a slurry, I'm assuming like an SBR slurry which from what I understand is made mostly from cement. My only concern is that this type of cement render will then not allow the wall to breathe. I guess I need a breathable slurry or render that will help with adhesion to the wall. What do you think?
 
Ok - I'm looking at limelite as this from what I've read is less expensive than using traditional lime but is easier to use but still retains the properties I need to allow the wall to breathe. I am however concerned about how it will affix to this type of earthy rubble wall. Mad monk suggested a slurry, I'm assuming like an SBR slurry which from what I understand is made mostly from cement. My only concern is that this type of cement render will then not allow the wall to breathe. I guess I need a breathable slurry or render that will help with adhesion to the wall. What do you think?
Sbr as said will seal it, I would await info from the lime guys, @seanlar @martinemj sorry if I have forgotten other experts on lime here.
 
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Pure lime is the only sutiable mat for this job Liam there are other options stud plasterboard wall incorporating air vents
 
I have recently bought a semi detached Victorian Property which is constructed from 9inch Solid Brick. I am suffering damp patches all along the party wall. There is a cellar beneath the property but next door have had there’s filled in some 10 years ago, they have also had their side of the party wall re rendered in what I suspect is either sand & cement or gypsum plaster. Both downpipes, front and back of the properties go into the main drains. The party wall on my side also has what I believe is gypsum plaster although I’m not 100% sure. I have removed 1 meter of this plaster to let the wall dry out whilst I decide the best course of action. I have asked next door what they have along that wall and there is barely anything, and no signs of damp there side although I suspect this is being hidden from the new render. I mentioned that the construction of my property is 9 inch solid brick, this is true with the exception of the party wall (where the damp is). The party wall seems to be constructed of a type of rubble, with bits of stone in it, but the cellar wall beneath is again different, this is more like a solid stone, but as soon as it reaches the ground level it changes to this type of earth, rubble with stones in it. (Ive uploaded a pic of cellar wall, and the damp of the party wall before i removed the plaster. I will upload pic of rubble wall asap)
I have read lots about chemical injections and the use of sand and cement with water proofer and I feel i should avoid this as this method would be just sealing in more moister damaging the fabric of the wall and not allowing it to breathe. I have read that the solution may be a lime based render with use of breathable paints which will allow the wall to breathe. However I am worried that I would use the lime render or an alternative that I’ve read about called limelite renovating plaster, redecorate with breathable paints but then still get the damp which would be a lot of effort and money wasted.

Any expert advice would be much appreciated
View attachment 2182View attachment 2183
Build a stud wall in front of it ,problem gone away ,you can render in this that or what ever ,always a risk , best of luck with it :RpS_thumbup:
 
The stud wall does seem a sensible idea for this party wall. I could them create a cavity and make sure that at top and bottom air can flow under floor joists at ground level and first floor level. The second option of using pure lime straight onto the party wall could be good too. I could then use an alternative like limelight for the rest of the ground floor walls to keep costs down. Good idea?
Lastly if I was to use pure lime just on this wall what would I use as a backing coat to ensure the lime sticks? Should I use SBR slurry? I'm worried this isn't breathable
 
SBR slurry involves cement which is not compatible with pure lime morters I think Liam you have been given the options make your own mind up but don't get it wrong as it could become a costly mistake.
 
Have a look at Mike Wye & Associates. Ita a good site for knowledge on lime.
you can use a natural lime version of SBR slurry which is applied using a Harling trowel.
lime products are not that expensive but the labour to apply is.
 
Could my brother who is a plaster but only has experience in S/C and gypsum give this a go or is lime a step too far for a plasterer without experience with this material?
 
Could my brother who is a plaster but only has experience in S/C and gypsum give this a go or is lime a step too far for a plasterer without experience with this material?

yes he will be fine, just be more patient with lime and there is plenty of inf o on here he can look at.
 
Ok - so sorry for all the previous indecision and questions but I think I've finally got a plan and I'd like to run if past the lime experts if possible.

Im thinking of using the company on the link below which can supply ready mix lime plaster. They supply the base coat which is just hydraulic lime and a course sand mix, then a finishing coat made again from hydraulic lime but this time a finer sand. I'm told I just add water. I'm thinking two base coats and then a finish coats. I'm told this should affix to the wall fine as long as I soak the wall with water beforehand. It's £10 plus vat for a 25KG bag.
Natural Lime

so thus is my an, good idea or not ?
 
Thanks lucius, I really appreciate all your expert advice. The link is a hyperlink. If you click on natural lime. This way of buying it could work out a lot more expensive though. Ill have to look at that.
 
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