House now grouted outside.
What do you mean, "grouted"?
What kind of material is applied around the outside? Looks like roofing felt.
And what is it good for?
I only know the drainage method (which catches and drains the water further down)
... now I’ve looked a bit longer and understood:
The "roofing felt" is only there to catch the falling mortar. The brick joints are being grouted...
Yes, the color of the joint (light or dark) makes a big difference. I know that from a natural stone house that was newly re-grouted.
Afterwards it was like a "new" house