Exterior Render on south facing wall has cracks around all windows and white blooming

Hi without looking at the job is sounds like water has got behind render...when water gets behind render in the winter it expands and therefore cracks turns up...you need to solve the problem or damp is going to get inside house ...you need to take off old render and render wall again.. Hope that helps you Les

Sounds like to me that it’s possibly wooden lintels on the outside or inside of a solid 9 inch wall, or possibly water ingress to the joists which sit in the wall. The stress cracks are a sure sign of lintel failure and the blooms are some sign of wood rot. Definitely not efferensense (salts) as efferensense appears as white powder on the surface where wet or dry rot appears like roots of a tree. Hopefully you will find this helpful. Regards Aled

First things first what render has been used if it's k rend. Or weber or any tape like them has he meshed it also around windows and sometimes around doors called stress cracks most the time it's because it isn't meshed right but sometimes new extensions can cause settling cracks but with the same any coloured renders any get a decent amount off water on them while in the drying process it will 100% change colour it will go to a white stain Iv done 100s of jobs biggest problem with rendering now is to many people think they can use it but haven't got a clue and there is no second chance with renders like k.rend

Lime render is the only way to prevent this happening, it will outlive any other material, cement is too brittle especially if the building is lime built