It wet regions it's beneficial sometimes to not insulate the rim joists at all. I've found rot behind foam board and batt insulation. We removed it and let it breathe, no more condensation issues. 🤷‍♂️

Mineral wool would have been a lot better on top of the foam. It is more fireproof, more inert, and especially a lot better for you in a fire since it will protect the foam from fire better than fiberglass. Highly recommend redoing the video to add mineral wool in addition to what you have already.

Thanks for the great info. Great job. Just one safety suggestion. Cutting foam like that with a miter saw can cast thousands of micro particles in the air that you breathe. You may want to wear a mask (didn’t look like I saw one, I could’ve missed it). Can’t be good for you.

I found that where the biggest air leak was is where the bottom plate meets the concrete. Spray foam does a great job sealing these air leaks

I think the latest advice is to not have fiberglass insulation at all in the basement. Better to add another layer of foam board with foil backing for both fire code and higher r values. Otherwise, great job!

Anything showing daylight or having obvious air movement should be sealed with caulk, preferably from the outside whenever possible. Larger holes should be closed with tin or wood shims and sealed with caulk and then insulated. Insects and vermin will chew through foam. The best practice would be to use closed cell spray foam approximately 3 inches depth and do a continuous spray from floor to ceiling. Also, the most recent data leans toward not using fiberglass bat insulation in basements as it will trap and hold moisture. Rigid foam board is a good DYI solution, it’s cheaper than spray foam but only if your doing the labor. Some areas require foil backed foam board to function as a fire barrier. Something else to look into is breaks. Most codes require fire breaks between each horizontal level of the building and vertical breaks at least every 10 feet of linear wall when using foam. In most areas 2 inch rigid foam insulation meets the R10 minimum insulation value for basements. Check with your local building codes before you start any work.

See that spider web, spiders choose a place that has a potential food source entering the area!

The foam board needs drywall in front to meet code for fireproofing.

In cold environments none of alternatives using fiberglass or foam board or spray foam are ideal. Moisture will travel through the wood joists (or the inevitable holes and gaps missed) and deposit on the cold surfaces of the rim joist. Now that the water is trapped, it begins to rot the wood. Ever wonder why it's impossible to keep paint on the exterior surfaces of wood windows? It's the same process .... moisture transits through the wood from inside the home and deposits between the wood and the paint on the exterior .... and voila .... the paint peels!! The only way to stop rim joist damage is to stop the rim joist from getting cold in the first place. This is done by insulating the "exterior" wall, rim joist and concrete foundation from the outside to keep it warm so moisture cannot get deposited on it from the inside. It took me years of research and thousands $$ in damage to figure this out and finally get control of the situation :)

The foam board may not be fire rated by code to be exposed. Good to check local code.

I just had fiberglass batt in the rim joist cavities. Pulled it out and put in foam board and spray foam to seal (like you showed), then put the fiberglass back in... no harm and adds just a bit more R-value. My suggestion for even better performance, especially in a crawl space or unheated basement... staple and seal "double-bubble" (Reflectix) insulation sheet to the bottoms of the floor joists and seal those joist cavities across the entire crawl space or basement. Greatly helps keep the floors warmer. Cheap and very easy to install.

Here in easterm Nc i see a lot of insulation contractors going through the trouble of encapsulating a crawlspace and then they leave fiberglass batts at the rim joist. This is the right way to do it. Nice work

Great video and perfect timing! I'm planning on redoing my ends this weekend.

Great advise. Like the vintage 70's Sears machinist box. I own the same from this time period. Retired machinist now.

Great video - definitely need to cover up those rim joists in Minnesota!

Excellent video! Thank you for the tips. I’m about to tackle this project and will be sure to post it on my channel.

Nice video. Thanks for sharing. I’m about to do the same job in my drafty basement here in Maine.

I hit the top plate edge where I could to seal that. No gaskets installed in older home. I used DAPtex Plus Multi-Purpose Foam Sealant, which is water clean up, and a partially used can is reusable months later. Around the rigid foam board edges I use standard expanding closed cell foam.

Fantastic rim job!

You need to use 4" foam boards or 2 time 2", home depot has 2" foam that is R13 so 4" gives R26, code is I think R30. Cut foam 3/4 less than rim joists size and attach transparent flexible plastic tube to foam gun so you can easly access everywhere... When you have 3/4 space you make 5/8 from each side so foam can go all the way towarst wood, this way you dont let air movements in front of the foam and also you dont need caulk.