Smaller chainsaws can be more dangerous than bigger ones, watch out for kickbacks and learn how to use a chainsaw properly so you don’t mangle yourself up. Do not get fooled by the lack of noise from an electric chainsaw, they can still fuck you up

Having said that, yes, you’ll be able to handle them more easily. I don’t know enough about that brand to comment on it, but as you said, you already have a bunch of batteries available for it. Watch your footing and have an understanding of possible tension and compression forces on those limbs

But do you really need it? Are debris a common occurrence on your hike? I won’t deny chainsaws can be useful to have around, but you mentioned it would only be used on the trail and you already have a sawsaw

Btw, which blade are you using on your sawsaw? You might want to get a pruning blade if you are using a standard carpentry blade, as they can be way faster too

Yeah, it might be a good idea to check if the downspout isn’t partially clogged. I don’t know how high that building is, but around here, leaves can get in there every once in a while

If you haven’t checked yet, you might also want to see the abutment flashing (see #7 below) where that wall and roof meet, as water might be percolating in that area and getting trapped between the ceiling/drywall/insulation.

I’d also check the other flashings as well while you are at it and if that drywall and insulation on that affected area are damp, remove them for venting

I can’t tell too much from the pictures, nor feel and test the wood. You mentioned the plaster was soft, but what about the wood? Are there mycelium growth in it?

Check if the wood is dark, mushy, deformed, poke test it with a knife/awl/screwdriver, as wood with advanced decay will be soft and the probe will penetrate easily. How far does it go? How big is the beam? Do you know what kind of wood is it? Test in multiple areas

Tear up a more of the plaster to check how the rest of the beam looks like and test them. If it is less than 0.3 cm, venting might be enough

Another one is the pick test, where you insert the knife beneath the wood grain to pry loose a thin section of it till it breaks free. If you get a long linear splinter, itś most likely good, if it comes out as crumbly chunks or short pieces with a mushy sound, it is not ideal.

If you are in a dry season and no rain in sight, I’d clean both inside and outside areas to let them vent. Get a fan/dehumidifier/open windows in that room.

I also prefer breathable buildings, so you could use a more traditional breathable plaster, which allows water to easily evaporate over time, whereas concrete and all the PVA might help trap the moisture. It is typically made from lime and/or clay, sand, and water. You can also add fibers (horse hair or plant fibers) for strength

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

I’m no specialist, but I’ll give my two cents. Anyone feel free to correct me if I’m wrong or a better approach is available

1. Yes, even galvanized steel will eventually rust when directly in contact with the ground and it was accelerated by the salty air from the coastal region. It also rusts faster in high humidity air/soil. Even after sealing the roof, it will rust again from capillary humidity from the soil if laid directly against it

2. Concrete or rock footing around 10-20cm above ground level is what I usually see, make sure the water drains and it isn’t pooling between footing and post. Those stirrups are usually galvanized steel, but if your post is already galvanized steel, I guess it wouldn’t make sense in your case

3. Based on the first image, if you were to use a concrete footing above ground, you might even be able to salvage this post, as the two screw holes look unrusted on the picture, and they seem to be around the level you’d need to cut. You might need to grind down the area and look on the inside to confirm it. If it is, you won’t even need new brackets

Otherwise, yes, a local shop will probably have some 90° brackets and bolts too. Keep in mind to accommodate the requirements for hurricane/flood/frost if your region is prone to it

Are you supposed to eat the burnt layer ? Is it just to add flavor and can be scraped? I usually don’t like burnt stuff, so I wonder how much it affects the taste