The linked pic shows the exterior where a plant is growing out of the wall. The wall is cracked and bulging. The pic is not good at showing 3 dimensions but the bulge is clear with a naken eye view. On the other side of the wall I could see the wood was a bit swelled and the plaster around it was very moldy. So I stripped off a lot of the moldy plaster. It was very soft from dampness. Fortunately, the mortar is still hard. Just the plaster was soft. Now looks like this:

Since the beam is likely structural, the safest option is probably to call in a pro. But fuck that, prices for pros are too crazy. I’m going to address this myself. My plan is to strip off all the loose concrete on the facade, as I hang from a rope (no scaffolding or ladder). I would then paint it with PVA¹ that is formulated for humidity and marketed to pros for the purpose of mixing with concrete. Straight PVA but diluted a bit with water as a 1st bonding layer. Followed by a slurry (small ratio of cement mixed with PVA & water). Followed by a thicker mixture for the 3rd bonding layer. And for the 4th stage I would do a normal blend of PVA + water + concrete and probably a plasicizer to get a heavy mix which will be the bulk of the render.

After rendering, I would never paint (I believe walls should breath), but I plan to finish with an “Aquaplan”-branded waterproofing layer, which claims to prevent water from penetrating (shows a pic of water beading up on a wall) while also claiming to be breathable.

What I am wondering is about this wood beam. I know there are costly chemicals for restoring wood which has been broken down by water. The stuff is supposed to penetrate into the wood and re-harden the fibers. I’m not sure what the chemical is or if it’s proprietary, but I wonder if I should try to track down that stuff and get it on the wood beam as a first step before rendering. Note that I won’t likely have access to the topside of the beam.

For longer-term protection, I might construct a small overhang so rain water is not constantly running on the facade in the future.

For the interior, I don’t think it matters what I do. I actually like the brick exposed for cosmetics and if I leave the wall open, it will help it breath and maintain a certain level of dryness (though limited in this humid region).

Anything else I should do, or not?

¹ polyvinylacetate