Advice on damp wall

[ashthekid]

I'm not sure if this is the correct forum for this question but I'm currently in the middle of a conversion project whereby we are building a timber frame property within the single skin of an existing old building that dates back to circa 1800's and used to be listed but is no longer. The old brick wall was covered in what looked like a thick mortar and horse hair mixture on the internal side that has literally fallen off in my hands in huge slices and now the external brick wall that is facing the street very closely is starting to grow mushrooms out of it! Quite clearly there is dampness within the wall and the grout between is a lime mortar by the looks of it that is very soft to touch as well. It was nothing like this before we started the project which is very confusing.

I attach photos of both the internal wall which I have now mostly peeled back to the brick surface and the external wall where mushrooms are now growing.

 

What can I do to overcome this issue and stop it from getting worse.

 

 

[Gus Potter]

Hello ashthekid.

 

You'll get lots of adivise and pointers here.

 

Look at the simple stuff first. Start at the top.. the roof and check gutters, down pipes and all the obvious stuff. If could well be that by opening up you have let the air into the wall, spring is on us and the wall is warming up, hence the fauna.

 

The pointing looks like it requires some attention so that the wall can dry out properly.

 

Just as an aside it looks like the wall on the outside maybe has had a flush of nutriants. Could be you have a lot of birds on the roof and if the gutters have been blocked you have washed fertiliser down the walls. This is a bit of an odd question but are you near a bonded warehouse, bakery as these can be associated with a black fungus.

 

 

[ashthekid]

The only change that has happened since the start of the project is the old slate roof was removed and had to be replaced with new because if it’s condition and then a new timber roof structure has been put on but not tiled yet. That has only been temporarily  felt and battened with long blanks laid across the front to protect the street from any falling debris. As a result the guttering was hidden so any rain falling on the roof was being directed directly only the brickwork rather than into the gutter. This week we have had a new row of wooden painted suffix which you can see from the photo below. 
It’s a residential street so no bakery or bonded warehouse nearby. 
 

You can just about see the joining terraced neighbouring property on the right and how it’s brickwork is immaculate in comparison. That’s how ours used to look before the project started.

 

I’m just worried what is happening now is causing irreparable damage. 
 

[DavidFrancis]

You say the gutter is currently covered over. To me, this would seem to be the cause?! (Water running down the brick/flint.)

[ashthekid]

Yes, no guttering at all currently.

I’m hoping when the new guttering goes on and new roof slates, it will stop this getting worse. 
But what can I do about it now? 
Just wash it off or treat it? It will need re-pointing for sure to replace the soft grouting in between the bricks.