Does recurring algae mean cleaning failed?
Not necessarily. Outdoor walls remain exposed to moisture and spores, and recurring conditions can encourage new growth. Review where it returns and any continuing damp. Treatment addresses existing contamination, not permanent exclusion or repair of every contributing building defect.
Should I book the same treatment every year?
There is no universal schedule. Suitability, exposure and actual recurrence should guide future work. Repeated application by habit can overlook a failing finish or ongoing water issue, so reassess the wall rather than assuming more of the same is always the answer.
Will black marks always be organic growth?
No. Similar-looking discolouration can have different causes. Whole-elevation photographs, close-ups and a description of changes help the assessment. A cleaning proposal should explain realistic improvement instead of guaranteeing total removal based only on the mark's colour.
Can an uneven coating be made uniform by washing?
No uniform recolouring is promised. Cleaning can reveal existing wear or variation after growth is removed. If the coating itself is failing, that may require a different response. Explain earlier products and discuss the desired appearance before work.
What precautions apply around a pond?
Identify it and its relationship to the wall and drainage before booking. The treatment and site arrangement need appropriate precautions and restrictions. Never assume a product is suitable beside water features merely because it is applied at low pressure.