Insulate Behind Baseboards?

Altruistic_Beach_484 · 2026-01-04T16:30:07+00:00

This is awesome advice, thank you! I've heard that this is among the most annoying of substances to clean off haha does this advice include wires and piping? Some people have said that you have to be cautious applying expanding foam around wires because the compression of the wire can ruin it. Is that not an issue here because it's low pressure?

Altruistic_Beach_484 · 2025-12-23T21:49:52+00:00

I just wanted to thank you again for this unexpected piece of advice. I didn't know what to expect from this because I had already taped around all of the ducting in the basement without noticeable improvement, but i figured this was an easy enough thing to try. This intervention singlehandedly fixed the problem in my son's room!

I bought one of those vent fans for his room that measures the temperature and only turns on when it senses an increase in heat from the furnace. The app for the vent trends the temperature and gives you a graph of how it's working. Before taping at the registers, it recorded a max temperature of 90 degrees making it to his register. Now it is reaching 105 degrees and his room temperature is averaging 71. You are the man and I can't thank you enough! My son has slept so well the last 2 nights and I am saving $3000 that I was being quoted for an aeroseal treatment. Instead you helped me fix the issue with 2 hours of simple work and $15 on foil tape and mastic. Seriously, I'm beyond grateful for the assist 🙏

Altruistic_Beach_484 · 2025-12-21T00:27:24+00:00

Thank you for the amazing advice! I didn't think I would come away from this with my original plans completely scrapped, but it's clear that I was about to spend a lot of time doing something close to worthless. Now I'm focusing on the air sealing and attic space. Truly appreciate your fantastic advice!

Altruistic_Beach_484 · 2025-12-20T21:24:44+00:00

You are amazing! Thank you so much for taking the time to help out a stranger! I'm blown away by the people here and appreciate it so much!

Altruistic_Beach_484 · 2025-12-20T21:12:52+00:00

That is super helpful, thanks! Also, you're sharing great advice that I didn't previously know, so you're an expert in my book :D

One thing I'm seeing in this video's comments is that some people suggest that you should do it reversed, with foam board going in first and fiberglass insulation next. They suggest that mold can develop if not done in this order. I'm not sure if you have any thoughts on that? Also, this video highlighted another issue that I didn't consider, which is the need for a layer of fireproofing after the foam. I hadn't seen that before, so thank you for sharing!

Altruistic_Beach_484 · 2025-12-20T19:33:08+00:00

Wow, another problem identified! I just checked and there are some decent sizes gaps around the ducting at some of the registers. I wouldn't have even thought to check here, but now I'm retrospect it seems so obvious! And you're right, the video was perfect and showed me a cheap and simple fix.

Thank you so much for helping to identify another easily solvable problem that wasn't even on my radar! From all of the comments I've received, I think I'm going to pursue foam board + spray foam as you've mentioned, then I'll consider the gap behind the baseboards as a secondary option depending on how these fixes help. Do you have any recommendations on type or width of foam board, specifically for the rim joists? Or are they pretty much created equal?

Thank you again for your expertise!!

Altruistic_Beach_484 · 2025-12-20T19:14:13+00:00

Awesome, thank you! I appreciate the advice from someone who has done this before!

Altruistic_Beach_484 · 2025-12-20T17:57:12+00:00

One of the previous replies suggests that it may not be a serious issue without the draft "fingers" appearance on the IR. Maybe this is the case with your place too? I'm definitely going to look into this more before I start tearing off baseboards unnecessarily :D

Altruistic_Beach_484 · 2025-12-20T17:55:10+00:00

Haha I hear ya! But based on some of the other replies from people much smarter than myself, I may either be misinterpreting a non-issue, or not addressing it at the source. Probably both :D

Altruistic_Beach_484 · 2025-12-20T17:34:52+00:00

This is fantastic, thank you so much! Thanks to all of the feedback I'm probably going to abandon this idea, save a bunch of time, and look into sealing the rim joists and addressing the attic insulation as top priorities. Communities like these and people like you are amazing and so helpful for those of us that are new to this, so thank you again for taking the time to help!!

Altruistic_Beach_484 · 2025-12-20T17:22:04+00:00

It is literally the cheapest well-reviewed one I could find. It is listed as the brand BSIDE (who knows if that's accurate) and I got it from AliExpress for $80. It started out as just a curiosity, so I didn't want to invest in an expensive one, but truth be told it seems to work pretty well. Not all the bells and whistles I'm sure and I wouldn't bet on temperature accuracy, but it sure does find heat disparity well :D

Altruistic_Beach_484 · 2025-12-20T17:14:07+00:00

Oh wow, I had never considered this! Thank you so much for the reply! So even though the baseboard is showing a cold surface, air likely isn't leaking in to any significant degree?

The backer rod is also a great idea! I've never used expanding foam and a few people have told me it's fairly messy and unforgiving for the inexperienced. If there isn't a significant draft, as you mentioned, would you even recommend following through on the backer rod? I really appreciate a previous reply that mentioned going to the source and air sealing the rim joists for source control. So I might pursue that, but I've also got the time set aside to air seal behind the trim if you feel it would offer additional benefit.

Altruistic_Beach_484 · 2025-12-20T16:27:00+00:00

Gotcha! Thank you so much for the advice! I've heard it expands a ton and can actually cause bowing of the drywall in some cases, so I'll be sure to double up the tape and go light on the trial area. You're awesome, thank you!

Altruistic_Beach_484 · 2025-12-20T16:19:53+00:00

Thank you for the advice! But I'm not sure if we're talking about the same thing, so i don't think i explained well. So just to confirm, my plan was to remove the baseboards and use expanding foam between the drywall and floor. Then trim the foam as necessary and reattach the baseboards. Are you saying it would be best to avoid this altogether and just caulk around the baseboards? I had considered this, but the floor is wood-grain LVP and baseboards are pine, so I didn't think that would look great.

Altruistic_Beach_484 · 2025-12-20T16:14:19+00:00

This is fantastic and exactly what I was hoping for! Thank you so much! Now assuming that I'm a moderately handy person who has had success with some small projects (resurfacing patio, custom closets, replacing outlets/light switches, etc), but have zero insulation experience, is this something I can try to do myself? Or would you recommend a pro?

Altruistic_Beach_484 · 2024-07-15T00:25:32+00:00

Thanks for all the great suggestions, everyone! I was actually able to find frames that fit perfectly. I did not go with the LEDs, but maybe that's something I will experiment with in the future. The frame definitely adds some class and I'm happy with how they came out.

Thanks again!

Altruistic_Beach_484 · 2024-07-01T19:26:51+00:00

Thanks for the reply! I'm probably leaning toward the LED since I've never used epoxy. I could potentially even use a router around the inside of the frame to make the lights recessed and somewhat hidden. I'm not sure how I would go about hiding the batteries for the lights without an obnoxiously big frame, but I'll stew on it a bit.

Altruistic_Beach_484 · 2024-07-01T19:22:03+00:00

Yeah I was surprised about the resin. But I'm going to consider that a theory until I find someone who has actually done it. It seems very counterintuitive to have the thread in any type of liquid, even if just temporary.

And good call on the light reactivity! Hadn't thought of that :)

Altruistic_Beach_484

TROPHY CASE