cold spots ?? damp ??

[thebigfella]

i`d been plastereing for 7 so it was about time i got a house and renovated it but ive got a problem, my house it was built in 1910 so its a sold 9" wall it had been injected with a damp proof agent and rendered over 20 years ago and there was no signs of damp but as a precaution i had it re-injected but was advised not to chop off the old rendered ( it was sold as a rock) so i pva`d and re-skimmed the walls and it was over 6 months before i painted it and it was all fine a year later when i moved in but over the last 6 months around the chimmey breast ive got cold spots which has started to make the paint flake off ? ive got vents in my windows and theres a small air flow but why has it started now ? i fell like choping off and rendering and putting a sikka sort of product and rendering it back up what do you think ? ( sorry its long and the spelling and grammer is shocking but i had my brains knocked out thats why im a plasterer)

 

[Jace]

is the chimney blocked up i.e no fire place

 

[thebigfella]

they`ve open but have a fire suround on which are cast iron and one has got rusty ? because off the cold/damp

 

[flynnyman]

Are they capped off at the top?

 

[thebigfella]

no there open ?

 

[Jace]

had it cleared in a while??

 

[lctanner]

jackdors.....birds

 

[thebigfella]

i need to get on the roof and have a look dont i:RpS_scared:

 

[uveco]

Post some photos, is it all over or in specific areas, are there salts showing?
The solid sand/cement you described may be too solid and trapping moisture.

 

[Chris W]

sounds to me like youve answered your own question - as in 'it was fine till you moved in, then 6 months later youre showing signs of moisture'...
its you thats introduced the moisture, its condensation, there isnt enough airflow...
the cold spots on the breast offer up a perfect place for moisture to condense...
i reckon dabbing some insulated boards to the breast and / or fitting a passive air vent will cure it..

 

[Jace]

sounds like chris is on the money although i would either go for the vent option or hack off exsisting and re render with lime mix to allow it to breath, if you have a working fireplace then i wouldnt go with boards

 

[Chris W]

if he had a 'working' fireplace, e.g. a 'real' fire then i doubt very much he'd have the 'cold spots' in the first place...

 

[thebigfella]

there not working fires ive thought about putting a "black box air vent " in the wall but not keen on the look will try and and upload some pics if that helps thanks for the replies so far hope i can get to the end of it soon

 

[Chris W]

might be draughty with a blackhole vent.. a passivents got a baffle in, fix em at ceiling height as opposed to floor height like a black hole...

https://www.triton-chemicals.co.uk/pdf/triton_passive_air_vent.pdf