Painting outside, couple of questions

[5oysterman2]

Afternoon guys, had a decorator booked in but unfortunately due to the continuous inclement weather he reckon he will not be able to do it this year.

Thinking about having a go myself.

I am responsible for the boundary wall between ours & neighbours.

Where should the boundary paint line be & how would I get a straight line up the wall because it's a pebble dash wall?

Previous owner has previously painted around window & doorstep but it looks terrible now.

What preparation(if possible )needs to be done to prevent it happening again?
We are near the coast if it helps. Many thanks for reading

 

[Wayners]

Coverstain then paint that green after preparing.
I'd not paint the pebble dash. You will be coating every few years

 

[5oysterman2]

Coverstain then paint that green after preparing.
I'd not paint the pebble dash. You will be coating every few years

Cheers Wayners, unfortunately it's going to get painted because previous owner started it but didn't finish the job & i bought the paint off him.
Preparation, is it just a matter of sanding it all before cover staining it?

Best way to get a straight line on walls? Many thanks

 

[Wayners]

Masonry masking tape and dab paint with brush. Then a small brush to fill in or scrape any bad bits and get it the best you can.
Sand and scrape off what you can.
Use peel stop if needed. Don't look like it's bad enough for that.
Read what primer is required on paint manufacturers data sheet