Damp circles on outer wall in ensuite

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millsy5

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I'm living in a new build (A rated) for just over 4 years. I've noticed for maybe the last year that damp patches have formed on the outer wall in the ensuite. All other rooms are fine.

The first ones to appear were the two directly above the window, on flat horizontal part of the window 'cutout' (not sure the proper name for this). These are exactly symmetrical with each other which is unusual.

Then more recently (some time after the summer) additional ones started appearing on the wall above the window, as well as an additional one right next to the extractor.

The outer wall has insulated plasterboard on the inside of the block.

The damp is worse after I have a shower in there.

I'm not sure if it's a ventilation issue as the extractor comes on with the light (I always ensure it is on regardless of whether I need the light on or not). Also the extractor itself provides ventilation even when off.

I usually have the window open during the day, until it's really cold out.

Any thoughts on the cause of these damp patches, and whether some damage might already be done inside the wall? I don't work in the building trade so don't really have a clue about this.
 

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I'm living in a new build (A rated) for just over 4 years. I've noticed for maybe the last year that damp patches have formed on the outer wall in the ensuite. All other rooms are fine.

The first ones to appear were the two directly above the window, on flat horizontal part of the window 'cutout' (not sure the proper name for this). These are exactly symmetrical with each other which is unusual.

Then more recently (some time after the summer) additional ones started appearing on the wall above the window, as well as an additional one right next to the extractor.

The outer wall has insulated plasterboard on the inside of the block.

The damp is worse after I have a shower in there.

I'm not sure if it's a ventilation issue as the extractor comes on with the light (I always ensure it is on regardless of whether I need the light on or not). Also the extractor itself provides ventilation even when off.

I usually have the window open during the day, until it's really cold out.

Any thoughts on the cause of these damp patches, and whether some damage might already be done inside the wall? I don't work in the building trade so don't really have a clue about this.
Yes
 
I just ran a magnet over the wall. It only stuck on the damp patches indicating that there are screws (or wall ties) here. Not sure what can be done here though.
 
Metal causing cold bridges/localised condensation. But quite large, and only after 4 years is unusual.

Suggest you get someone to carefully take out the fan extract and try to have a look at the damp patch next to it. e.g is there a void behind the insulated board that has become blocked, did they dab aswell or use wood blocks etc etc.
In theory the NHBC Guarantee should cover it but don't hold your breath on that. Ask neighbours if they've got it aswell - somebody might already have the answer or the same problem.
 
Suggest you get someone to carefully take out the fan extract and try to have a look at the damp patch next to it. e.g is there a void behind the insulated board that has become blocked, did they dab aswell or use wood blocks etc etc.
I removed the cover off the fan and was able to see through to the outside vent. Looks like there is mortar all around the circular cutout so nothing obvious
 
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