In the past 2 months, I used a carbide 2.5" paint scraper to remove the
many layers of built up paint and the crappy blobs of texture from all
vertical walls in my 1973 built POS.
This process left many divots where the texture pulled off the wall,
but by using 2 coats of thinned mud, after sanding the wall was
perfectly smooth. In addition, like yours, the tapped seams were
terrible, but when I was finished they were nearly invisible.
IF you scrape your walls, you don't want to go through to the drywall
surface, just knock off the high spots, so when you apply new mud, it
goes on smoothly. Something that really helped me was thin mud and
using a broad knife. When applying the second coat, spray the wall
lightly with a mist of water after getting the mud relatively smooth.
It's impressive how smooth the mud turns out, ultimately it needs just
a touch from the sander. I found it easier to scrape and smooth with
mud than applying new mud over the top with out scraping which took
something like 4 coats. Don't know what your situation is...but I at
the same time I scraped the acoustical texturing off the ceiling (glad
that crap is gone!).
One wall in particular had many bubbles under the tape, and what I
learned was the original tappers filed massive cracks with mud, which
later on, pulled away from the tape. If you have to remove the tape,
take a knife, cut along each edge of the tape, through the mud and
paint. With a putty knife and a spray bottle, start at one end and
lift the tap out of the joint. Spraying a small amount of water on the
tape really helps it to let go of the mud. Repair the mud in the
joint with a narrow knife (I used a putty knife) making sure to keep
the edges of the channel relatively clean. Lay new tape back in the
track with fresh mud, feather the edges you'll be good to finish like
it was new. Again...if there's massive amounts of mud on the
seam...the paint scraper works well to level out large bumps, surforms
work well too.
When you get the walls like you want, grab the texture gun and get to
work. Granted this is a lot of work and wouldn't wish it on
anyone...but the house looks fresh and renewed, and I'm glad I did it.