Diff between Rising damp and condensation?

Gingernuts31

Hi folks,

I think I have rising damp on the external (internal) walls on the older part of my 1940's house. Extenstion to the back built about 10 or 11 years ago and that seems to be fine. I have the usual black mould which I know if from poor ventilation but the plaster has come away from the walls and not just to a height of 1.5 meters. In some area's of the external walls the plaster is away from the wall and sound hollow even at about 2.5 meters but only in patchs.


I had 2 companys out and the first told me it was just condensation because the attic was not insulated. I got the attic insulated and got the 2nd company out. The 2nd company said its rising damp.

Who can I trust? If they both tell me diff things and obsivously I'll need to be sure which problem I have so it can be treated properly.

Thanks you the input.

sydthebeat

it could be both....

pics would be a help here.

Gingernuts31

Hi Syd

sitting[1].jpg

sitting.jpg

sitting2.jpg

boxroom.jpg

The ones of sitting room were alot worse I just cleaned the wall the other day so got rid of most of the mould but you can still see where it was. The line going across the wall is broken plaster its come away from the wall.

Gingernuts31

And this one bedroom.jpg

muffler

Are you finding this on all parts of the walls or just behind furniture etc?

Gingernuts31

All parts even areas with nothing in front of the wall. Bear in mind the plaster it hasn't come away in all areas. The pic showing the bedroom with the paint gone off the wall the peach type color the plaster is still on the wall doesn't seem to have come away at all in that room but in the blue room I was able to knock of a good chunk of plaster and see the cement covering the brick but I only ever notice a small wet patch on that in the corner and it never extends more than a foot or so up the wall but yet the plaster was able to come off no problem.

sydthebeat

i assume mass concrete walls??

DanWall

Rising damp will bring hydroscopic salt up and form a salty white crust on the wall. Condensation usually forms black mold

Gingernuts31

Not 100% on mass concrete. The neighbour next door his son used to own this house and they never got it treated either but from what I can gather is that they never really lived in the house. The neighbour says the walls are pure concrete. Not concrete block just concrete he says. In the attic I think at the eve's I think I can see blocks but not sure.

The guy who did the survey said its 215 solid blocks but thats the same guy who didn't spot the damp in the first place because the last prick just plastered over the affected walls to cover it up for the sale and survey was done on a dry sunny warm day :mad: Wish we had of looked at buying in the winter then it wouldn't have passed the damp readings.

Gingernuts31

DanWall wrote: »

Rising damp will bring hydroscopic salt up and form a salty white crust on the wall. Condensation usually forms black mold

Tbh honest I haven't come across the salty white crust at all just black mould and detached plaster. The guy who said it was condensation said once the attic was insulated it would sort it out but bit hard to tell as attic is only insulated last few weeks but he also had to inject a DPC into the walls. Why inject a DPC if he says its not rising damp?

sydthebeat

Gingernuts31 wrote: »

Tbh honest I haven't come across the salty white crust at all just black mould and detached plaster. The guy who said it was condensation said once the attic was insulated it would sort it out but bit hard to tell as attic is only insulated last few weeks but he also had to inject a DPC into the walls. Why inject a DPC if he says its not rising damp?

well thats completely wrong...

once the attic is insulated the problem will get worse... warm air carries more moisture than cold air, so by making the rooms warmer you are increasing the relative humidity in the rooms, and you are also increasing the temperature differential between the air and the surfaces, thus causing more condensation, and more cases of it.

Ventilation is key.... check building regulations for minimums.
also insulation of the walls is a must, preferably externally if you can afford it.

if its rising damp, the warmer internal temperatures will help keep the moisture pushed down, but i would recommend internal drylining if its rising damp, which i wouldnt think so judging by what you are saying and what the pics show. But short of an on site visit, thats only my opinion.

Gingernuts31

The room with the plaster and mould issue don't have any vents except windows which in the current temps don't get opened up too often. The sitting room and box room have suspended wooden floors with a vent to the front under the floor level of the house and that vent is letting the air in under the floor. So the only ventilation is actually coming from under the floor and thats a no go in box room as there is carpet down.

I see in my previous post I said He had to inject a DPC. He didn't inject anything we never got him to do the work so does that make any diff as to IF its damp or condensation? As far as I know there is no DPC in it at all.

BryanF

Gingernuts31 wrote: »

I have the usual black mould which I know if from poor ventilation but the plaster has come away from the walls and not just to a height of 1.5 meters.

it would seem as suggested above that you have an issue with both condensation and actual damp

I had 2 companys out and the first told me it was just condensation because the attic was not insulated.

this was a ridiculous assumption to make, assuming there were no other recommendations made - such as (this is the order you should carry out works)

• ventilation in each room - mechanically in Wc and kitchen (at the very minimum)
• diagnosis of cause of damp and damp proofing measures to solve
• insulation secondary to the above to raise the internal surface temps
• a constant basic level of heating (once above are achieved)
• sensors installed to insure the humidity remains at reasonable levels or further mech ventilation measures such as demand control/ positive input ventilation are installed

I got the attic insulated and got the 2nd company out. The 2nd company said its rising damp.

Who can I trust? If they both tell me diff things and obsivously I'll need to be sure which problem I have so it can be treated properly.

Thanks you the input.

can i ask more about the two companies?
were they

1. builders
2. architects
3. engineers
4. surveyors or
5. damp specialists?

Gingernuts31 wrote: »

who didn't spot the damp in the first place because the last prick just plastered over the affected walls to cover it up for the sale and survey was done on a dry sunny warm day :mad: Wish we had of looked at buying in the winter then it wouldn't have passed the damp readings.

that may be masking the source of the rising damp issue.

Gingernuts31 wrote: »

Tbh honest I haven't come across the salty white crust at all just black mould and detached plaster. The guy who said it was condensation said once the attic was insulated it would sort it out but bit hard to tell as attic is only insulated last few weeks but he also had to inject a DPC into the walls. Why inject a DPC if he says its not rising damp?

this makes no sense get another opinion or a more professional consultant

Gingernuts31 wrote: »

The room with the plaster and mould issue don't have any vents except windows which in the current temps don't get opened up too often.

do you mean to say that neither of the 'companies' suggested this as a possible cause for your troubles????

The sitting room and box room have suspended wooden floors with a vent to the front under the floor level of the house and that vent is letting the air in under the floor.

that doesnt count as ventilation

I see in my previous post I said He had to inject a DPC. He didn't inject anything we never got him to do the work so does that make any diff as to IF its damp or condensation? As far as I know there is no DPC in it at all.

???

• if there is no ventilation there may be mould.
• if there is no DPC(damp proof course) then there may be rising damp

as far as i can make out you have been hiring tradesmens to assess problems that at the very least require an arch/surveyor/engineer who will then enlist a specialist damp consultant is required or at least specify the list of works required in a similar order to what I have outlined above

BryanF

sydthebeat wrote: »

if its rising damp, the warmer internal temperatures will help keep the moisture pushed down, but i would recommend internal drylining if its rising damp, which i wouldnt think so judging by what you are saying and what the pics show. But short of an on site visit, thats only my opinion.

I dunno about syd, I suppose its a decision to be made on site. going with a tanking membrane to the internal walls followed by drylining.. I prefer the DPC route myself especially as the OP has sus floors, along with external measures like lowering paths etc

Gingernuts31

BryanF wrote: »

it would seem as suggested above that you have an issue with both condensation and actual damp this was a ridiculous assumption to make, assuming there were no other recommendations made - such as (this is the order you should carry out works)

• ventilation in each room - mechanically in Wc and kitchen (at the very minimum) The 1st company did not mentioned ventilation at all. The 2nd told me id need a positive ventilation system.
• diagnosis of cause of damp and damp proofing measures to solve. 1st company wanted to inject a dpc. 2nd company wanted to install electro.
• insulation secondary to the above to raise the internal surface temps. Both companys suggested drylining the external walls.
• a constant basic level of heating (once above are achieved) Neither suggested having constant heat on to keep temps normal.
• sensors installed to insure the humidity remains at reasonable levels or further mech ventilation measures such as demand control/ positive input ventilation are installed. As above positive ventilation system.

can i ask more about the two companies?
were they

1. builders
2. architects
3. engineers
4. surveyors or
5. damp specialists

Yes damp companys who count themselves as specialists.

do you mean to say that neither of the 'companies' suggested this as a possible cause for your troubles????

The 1st company didn't mention the windows I don't think. The 2nd one only asked about the kitchen and bathroom windows.

• if there is no ventilation there may be mould.
• if there is no DPC(damp proof course) then there may be rising damp

as far as i can make out you have been hiring tradesmens to assess problems that at the very least require an arch/surveyor/engineer who will then enlist a specialist damp consultant is required or at least specify the list of works required in a similar order to what I have outlined above

• ventilation in each room - mechanically in Wc and kitchen (at the very minimum) The 1st company did not mentioned ventilation at all. The 2nd told me id need a positive ventilation system.
• diagnosis of cause of damp and damp proofing measures to solve. 1st company wanted to inject a dpc. 2nd company wanted to install electro.
• insulation secondary to the above to raise the internal surface temps. Both companys suggested drylining the external walls.
• a constant basic level of heating (once above are achieved) Neither suggested having constant heat on to keep temps normal.
• sensors installed to insure the humidity remains at reasonable levels or further mech ventilation measures such as demand control/ positive input ventilation are installed. As above positive ventilation system.

can i ask more about the two companies?
were they

1. builders
2. architects
3. engineers
4. surveyors or
5. damp specialists

Yes damp companys who count themselves as specialists.

do you mean to say that neither of the 'companies' suggested this as a possible cause for your troubles????

The 1st company didn't mention the windows I don't think. The 2nd one only asked about the kitchen and bathroom windows.

sydthebeat

BryanF wrote: »

I dunno about syd, I suppose its a decision to be made on site. going with a tanking membrane to the internal walls followed by drylining.. I prefer the DPC route myself especially as the OP has sus floors, along with external measures like lowering paths etc

im not at all convinced about an injected DPC into a mass concrete wall.
Thats why id suggest internal dry lining along with measures already ie EWI

Gingernuts31

sydthebeat wrote: »

im not at all convinced about an injected DPC into a mass concrete wall.
Thats why id suggest internal dry lining along with measures already ie EWI

What about Electro Syd? I believe this is more full proof but you read reviews. Some people say it works great others say it doesn't work at all. Can it be installed wrongly to the effect that it won't work?

sydthebeat

tbh ginger, ive never had a project where it was used. same as you ive read great reviews and others which denounce it completely.
I can sort of understand the polarity effect that it works on, but i cant see how it negates simple capillary action.

Gingernuts31

Yes I was thinking the same thing. If I had my way and the money id knock down the affected walls and put in a heavy duty plastic sheet the types they use in new builds and rebuild the walls. I wouldn't need electro or french drain then sure I wouldn't?

Is that an option do you think? Trying to take down effected walls without the attic and whole front of the house caving in?

BryanF

sydthebeat wrote: »

im not at all convinced about an injected DPC into a mass concrete wall.
Thats why id suggest internal dry lining along with measures already ie EWI

I'd be leaning towards the electro osmosis, I had had positive results with the system

Gingernuts31

Have you used the system much Bryan? Im a bit weary of it to be honest but im also weary of the injection DPC as I don't see how it can expand through cement. Like I said id rather try support the walls and build up from scratch with french drain or something.

BryanF

Gingernuts31 wrote: »

Have you used the system much Bryan? Im a bit weary of it to be honest but im also weary of the injection DPC as I don't see how it can expand through cement. Like I said id rather try support the walls and build up from scratch with french drain or something.

ye I've used it, its quiet common in conservation practice - although in these energy saving times it does require about the equivalent of a light bulb to run. how will you know where to stop with the demolition of external walls? internal walls? lift floors? - best of luck with whatever you decide

Gingernuts31

BryanF wrote: »

ye I've used it, its quiet common in conservation practice - although in these energy saving times it does require about the equivalent of a light bulb to run. how will you know where to stop with the demolition of external walls? internal walls? lift floors? - best of luck with whatever you decide

I won't know where to stop exactly height wise :eek:. The internal walls all seem to be fine tiny bit of mould on the that crept over from the external walls but only a tiny bit when you consider how bad the exernal walls are. Out of the 4 rooms effected 2 of them have suspended wooden floors and the other 2 have concrete I think. Tbh I think im living in a dream world with regards to that job. I called house insurance yesterday to see if they will cover work to be done ( electro + french drain, positive ventilation system) I doubt they will pay for the walls to be insulated but may pay for them to be waterproofed. Waiting on a call back from them today so hopefully .