Damp in fireplace.

ShaunOB992

We have recently bought a 1930 semi detached house and had the property renovated. We opened up the fire place and created an opening. This was then boarded a dot and dab arrangement. The fireplace is on a party wall. Now when it heavily rains, wet patches seems to appear. They seem to dry when the weather stays dry for a long period of time. I have arranged for someone to go up onto the roof to investigate further in 2 weeks time. However does anyone have any ideas what the patches in the photos could be? I appreciate it's hard from looking just at a photo.

daveyjp

Is the photo the boarded over fireplace opening?  If so that's your problem.

Damp in the chimney simply can't dry out as there is no airflow.  It needs opening back up.

Bendy_House

I think that might be the back of the fireplace recess? (But, good point - has the roof of that opening been ventilated into the disused flue? And has the chimney pot been ventilated-capped?

If that's the FP back, then the p'board is D&D'd against the party wall, which I suspect it having rain come down what is presumably either a cavity, or else a gap/layer between the two brick skins. The wall is wet, and this passes through the dabs.

Have you had a look up in the loft at the party/fire wall there? Any signs of wet?

I suspect you are on the right tracks with your suspicions. 

ShaunOB992

Thanks for the quick responses. 
Yes we have put roof cowls on the chimney pots, these roof cowls are the ones with side openings in them to allow ventilation.
I have been in the loft yes and the chimney breast is slightly damp up there.
Would that suggest something is coming in from above?

The fireplace opening is boarded at the bottom but I core drilled some openings in it a while back to allow ventilation to flow.
As it gets worst with the rain, my gut is saying something is getting in from above?

Doozergirl

That's the obvious answer that the symptoms are pointing to, yes.  

The breast in the loft should be able to breathe adequately if it's not been covered, so if it's damp then it's likely a leak.  

Check the flashing around the chimney first.  

ShaunOB992

Ok thanks guys.
Will get someone up there to investigate.

stuart45

Have you got any photos of the chimney stack?

FreeBear

Doozergirl said:

That's the obvious answer that the symptoms are pointing to, yes.  

The breast in the loft should be able to breathe adequately if it's not been covered, so if it's damp then it's likely a leak.  

Check the flashing around the chimney first.  

Flashing (or lack of) would be my second guess after a cowl. If both of those are in good order, then that leaves the flaunching at the top of the stack. With a shared chimney, I'd also look on the neighbour's side and see if their pots are capped on any unused flues.