My wall is becoming transparent!

[diynoobie]

Hello all.
I am decorating a room and I noticed that I can see the outline of the breezeblocks on one wall of my room. I attach a piccie (I hope you can see it, it is faint).

The outlines of the bricks are a faint darker colour.

Can I just add a new coat of paint? or should I reskim?

PS - there was earlier damp in that room but not sure if that has a bearing..,
Thanks
N
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[dcdec]

Is the paint dry in the picture? as the problem often goes away with drying. Its all to do with thermal properties.

 

[Space cat]

there was earlier damp in that room but not sure if that has a bearing..

That would be my guess. The blocks have dried out faster than the cement and the higher moisture content of the plaster over cement is making it darker.

But I'm not a builder so might be wrong ---

 

[diynoobie]

Thanks for looking guys. The paints been dry for years!

It only affects 1 wall too

 

[dcdec]

So you havn't painted it yet.

Dirt (could be caused by burning candles or a coal fire for example) its drawn in by warm air and where the wall is colder it doesnt stick. Its to do with the thermal properties of the materials, the mortar is colder so to speak. I probably havn't explained the technicalities that well but it is the problem, when you paint it it is likely to dry showing the outlines but once dry should be ok.

 

[dcdec]

If it only affects that wall its probably external

 

[diynoobie]

yup, it's an external(ish) wall (there is the outer brick wall, a small gap and then my neighbours garage betond the breeze blocks.

if the dirt/soot targets external walls then maybe that could be it - i'l try scrubbing it and see if it comes off...

 

[Space cat]

You get more condensation on external walls. The coldest parts (mortar) collect the most water then the water traps the most dust.

 

[Nige F]

They are big blocks - maybe Durox - they need a protective coat

 

[joe-90]

When my wall became transparent - I called it a window.