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
If that beam is structural and rotting you’re going to want to fix it before it becomes a way more expensive problem. Once things start sagging it becomes an enormous job to fix.
Are you sure all that humidity is coming from the outside? It looks like a really weird spot for that to happen
Why can’t you access the upper floor? Is this an apartment building and someone else lives above you? What’s in the black tube?
Perhaps you have already checked, but I’d try to rule out any infiltration coming from above, otherwise it will keep happening and it could get worse. If someone lives above you, they might actually be liable for these repairs depending on the laws of your country
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
My guess would be that this is just pure epoxy (not the two component epoxy glue you normally buy that includes plasticisers etc.). Epoxy can penetrate wood quite well, but you need to make sure the wood is really dry again before attempting this. Probably needs several weeks of drying.
You might consider adding or replacing the flashing when rebuilding the overhang.
