Damp in 3 different places

[wannadie]

Friends house. Noticed damp in 3 places. What could it be and how can this be treated?

Photo 1 why is it a brown colour? Photo 1&2 - connecting wall between flat properties, ground floor. Photo 3 - washing machine behind wall

Flat has been empty for a month or so, so it is a mystery.

 

[jj4091]

Photos 1 & 2 possibly leaking pipework behind skirting. Photo 3 = check behind washing machine.

 

[wannadie]

Is it normal for the mould to go a brown colour?

 

[jj4091]

Depends whats leaking