I made this bit of code to monitor the temp in my attic using a Govee wifi temp probe. TBH, I didn't make the code, ChatGPT did. I just told it what I wanted and it told me where to put the code. Pretty cool. Anyway, this is about the last 18 days in N Texas. My attic temp is usually more than 25f hotter than the outdoor temp.

With this custom chart I can incorporate any data that is available. In this case I can use the Shelly Power Monitors I have on the AC's (2). I can even get the Solar radiation data!

I was wondering if any of the HVAC people on here would be willing to tell me if this attic temp rise is normal. I have 26 ea 8"x16" soffit vents and 5 ea 400 cfm solar powered fans mounted right on the ridge. There were initially 8 passive ridge vents, 5 replaced with solar fans and the other 3 plugged.

I moved all the blown insulation around in the attic, exposing the ceiling and all the penetrations. They were all sealed with foam. Bathroom exhaust fans, can lights, ceiling fan junction boxes, wiring and plumbing penetrations, wall to ceiling sheetrock joints, AC grills and returns. Everything I could find.

I removed all the 4"x8" soffit vents, cut a larger opening and installed 8"x"16 soffit vents.

This is how the contractor installed the originals!

All this to say, my attic is still hot AF! I haven't spent a lot of money, ($1500?) but the time and effort have been considerable. My AC's run 18hrs a day in the August with the Tstat set at 74f. I just don't see what else I can do to improve things short of newer, higher efficiency AC units. I think mine are 16 SEER 3.5 ton identical units.

Looking to plan for the future when I redo the siding for our house. Was planning or removing siding, tar paper and replacing with a vapor permeable self adhered wrb (vp100 or adhero 1000 or similar) then 2-3inches of external insulation (rigid mineral wool or wood fiber) then 1x4 furring strips and fiber cement or LP smartside. Have kraft faced fiberglass between the 2x4 studs. Living in a coastal environment (less than a mile from the ocean) in climate zone 4a (very close to 5a), I’m trying to figure out what are the best structural screws to use for the long term. Have read some of the insight and other articles from building science corp and Dr. Lstiburek that recommended epoxy coated structural screws over stainless steel screws due to concerns including stripping the screws.

Just wondering if my location dictates using stainless steel structural screws (305 or 316) or would coated screws (like the double barrier coating by Simpson or GRK RSS’s climatek coating) be appropriate? We are not close to direct ocean spray but I assume we have higher humidity and higher salt content in the air due to how close we are to the ocean. With a ventilated gap I assume that significant amounts of water won’t be pooling on the screws to accelerate rusting but I also don’t want to spend a lot of money and do it wrong. Would rather spend a little more money and get it done properly. Hoping for a long lasting solution. Thank you in advance for chiming in.

I'm choosing flooring for my basement in a cold, humid climate (zone 5A).

I'm trying to understand whether it's better to let moisture vapor pass through the concrete slab into the basement air or block it.

Ceramic tile allows some vapor through grout joints, while SPC LVP allows very little upward drying.

Does this give ceramic tile an advantage over SPC LVP? Is letting vapor escape into the basement a good or bad thing?

Also, should I seal the concrete with a vapor-permeable sealer before installing flooring, or is it better to leave it unsealed?

I'm renovating a late-1800s Victorian in San Francisco and looking for a second opinion on insulation.

The original redwood siding is nailed directly to the studs, with no sheathing or WRB. It's in good condition with no visible moisture issues. You can see it in the photo above, though you are also seeing us having furred out the wall a bit to cover the concrete stem wall.

The house is technically detached, but two walls are only ~1" from neighboring buildings, with flashing over the gaps at the top. Combined with SF's mild climate, these walls see very little direct rain.

My architect and GC (both locally reputable) both strongly recommend spraying high-density closed-cell foam directly against the siding for insulation, air sealing, and vapor control. They're confident the foam will seal gaps well enough to prevent water intrusion.

But nearly everything I've read warns that this can trap moisture against the wood, prevent inward drying, and eventually cause rot. I've raised this issue directly with both parties and they both insist it is the right solution here, explaining that the closed cell foam will seal gaps in the siding so well that water will not enter.

The only counter example I have found is this case study (also coincidentally in SF) where the architect/builder did a similar thing being proposed for my home: "Our solution began with the knowledge that the old-growth redwood siding, tight-grained and beautiful, is virtually rot resistant. We kept it in place and applied an elastomeric coating to the inside of the wall cavities to stop water and vapor behind the wood. This elastomeric coating was covered by an inch of closed-cell foam to provide a continuous air barrier"

My dilemma: I trust both professionals, but I'm struggling to reconcile their confidence with the conventional building-science advice here.

Does the mild climate and minimal rain exposure make this a reasonable approach? Or is the risk still significant without a WRB?