Cutting access gap in sleeper honeycomb wall in crawlspace

[GhavGrim]

Hi! First time here - could really use some help and unusually, Google hasn't helped me this time - neither has the forum search.

So, I bought a new house, 1970s Bett bungalow. It needs a lot doing, upgrading the electrics being one of the first priority jobs. No existing hatches, so I cut an access hatch at the back of a cupboard in between the joists.

//media.diynot.com/220000_219789_79319_75144758_thumb.jpg
//media.diynot.com/220000_219789_79320_81326984_thumb.jpg

Unlike my last house, this one has no gap in the sleeper walls, so my hatch only grants access to the first ten feet of the crawlspace. There's two honeycomb sleeper walls down there. Good news is, everything seems dry, relatively clean and ventilated.

//media.diynot.com/220000_219789_79321_71346735_thumb.jpg

I'd like to cut a gap in the wall, between the joists, to avoid having to cut more hatches in the floor. I was thinking drill with my largest masonry bit, then follow up with a masonry blade on my circular saw. I don't want to undermine the joists though.

Whats the best way forward here:
> Get on with it, cut a gap?
> Cut out the bottom four rows of bricks, leaving the top two?
> Don't cut it at all, ever?

Should I be thinking about support pillars either side of the gap, a RSJ, or anything else here?

 

[tony1851]

Should I be thinking about support pillars either side of the gap, a RSJ, or anything else here?

Just how wide a gap are you considering?
If it's just to crawl through from one part to the next, 18" or so should be perfectly adequate. At that width, you wouldn't need any thing to support the timber wall plate.
Also, if space is restricted, don't take power tools down there - just a hammer and chisel.