Hollow sounding outside wall

The wall itself will be boss, this means that the render has came away from the brick. That’s why you can hear a hollow sound. You would be best getting that checked out

Hi If I was you definitely I will call back and to have look at again but You have done it with the sound and cement you going to have always problem the best solution only that Silicon rendering can solve your problem Once and for all

It can happen with sand & cement. Especially if it’s cured to quickly in direct sunlight. So many new systems out there now with silicone & monocouche renders. Like someone has said silicone would have been the best choice or a monocouche coloured render with a sealer to stop it staining especially from the water running of the fence. Not really the applicators fault and if he’s put all the correct admixtures in it should be fine. When it starts falling of the wall then you need to worry. Regards Stuart.

Hi the rendering is not adherd to the wall behind there for you can get water penetrate through the rendering which will only get worse. In winter it can freeze and blow the rendering off not ideal.