We had a small (14'x10') bedroom gutted recently, and we need to insulate the walls before redoing the walls/windows.

We're leaning towards closed cell foam because of its higher r-value, but I've read scary things about dry rot etc. Is this a concern with a 2x4 wall in an older home with cedar shingles on the outside? Pictures show the room.

The title, basically. House is a mix of OSB and ox cardboard and foil type sheathing, wrapped in house wrap. All the houses in this development are vinyl sided, so I assume this one will be too

They caulked all the corners and the top plate and a bunch of 2x4s that support a beam. Is this a regular practice? Whats the point? Last in progress house I've seen inside of was about 20 years ago, and I don't remember seeing this.

The home is more than one hundred years old. I've heard horror stories about installing spray foam in old homes in particular.

There's all the usual concerns - off-gassing if mixed badly, etc. We also know the roof has had a tendency to leak in the past, and I'm worried about hiding moisture damage. Our roofing contractor also said spraying foam on the attic wood would void their warranty.

On the other hand, our attic insulation is shit, our utility bills are high af, and our climate is both hot and cold af, so we have to do something, and probably something with a high R value.

When I took these concerns to the insulating contractor, he said that he would be installing the foam on baffles and not directly spraying the wood itself. He said the baffles would leave an airstream, which I guess helps prevent the foam from insulating too well.

What do you guys think? Is foam on baffle way better than foam on wood directly?

Took 5 months from start to finish. I live in the Northeast, so kept floor joists insulation however replaced R19 fiberglass with R30 Rockwool. Air sealed everything and installed 15 mil vapor barrier made by Stego. Installed Aprilaire e080 standalone dehumidifier which drains into laundry tub located in garage. Relative humidity kept at 55%. Entire house is less humid and can definitely tell a difference in air quality. Also replaced a bunch of electrical wiring that was old throughout the house.

Just recently moved into a house and one of the walls on the basement is breaking in half, tilting inwardly. There’s a crack on the whole wall and the column is bending as shown in the picture.

How worried should I be? We are only renting the house. This is in Indiana, USA so is very hot half of the year and very cold the other half, if that’s important.

I know basically nothing about this subject, so I don’t know what is relevant to mention so if there’s something you need to know, please ask me.

Thank you in advance for the advice!

I'm very pleased with this storage solution, mostly clothes in the bins so 50ish pounds each. However I'm concerned this is too much for the trusses to handle. How can I calculate if this is safe?

Update: Thanks, everyone, for all the help! I found a lumber stamp identifying the mill in BC, but couldn’t identify the truss manufacturer. The original house drawings only say “Final Truss Pattern Per Manufacturer.” I’ve reached out to the builder too—at this point, I’m curious to get an answer.

Inspired by u/rrapartments’ comment, I’ve removed five bins and spaced the remaining ones out more evenly to bring the load down a bit. I still don’t know whether that’s sufficient. I also hear the broader point that getting rid of all this BS is the best solution. Point taken!

I’m honestly thrilled with the responses here. In an age when ChatGPTing everything is so tempting, I’m glad Reddit can still summon the collective knowledge of 100 people. Really appreciate everyone taking the time!

I have a house which desperately needs a cheap heat removal solution. Ok I know this is a big problem so it’s not going to be nothing but the costs could be astronomical (aka we can’t do it!) unless someone thinks of something smart.

Area - very large and open plan. A long rectangle area attaches to a square area. Yes that is a tarp covering my roof 😭
Problem - high vaulted ceilings and a glazed roof. Ie. a giant greenhouse with no ventilation.

Solutions I am exploring:

1. change fixed roof lantern on square area to opening windows - too expensive as that would be custom redesigning the whole roof design/load.

2. Add film to the sky lights in rectangle area - quoted 1.6k and think we have no choice but to do this

3. Add a roof vent into the tiled part of the square area - how do we close this in winter? What does the inside look like?

4. An AC unit - my energy bills are already 6k a year on this house I cannot be putting in more money spending things.

5. Your bright ideas to save me from going bankrupt or dying of heat stroke 🙏

Perhaps this will be a little bit of encouragement for any other owner builders out there. I have no construction experience but with a bit of research great things are possible. My build is a sheathingless double stud wall in CZ7 using pro clima products (Intello plus and solitex mento plus. The central wall cavity is dense packed cellulose and the interior stud bay is Rockwool.

This blower door test was pre drywall. As you can see under 0.2 ach! Interior volume was 36,000cu Ft.

What, the ef, is going on with the oversizing of heat pumps Air Conditioners? I have recently jumped head first into home performance and it's every house I go into now. If they've had a new unit installed in the last 3 years, it was sized up because the old one "couldn't keep up" and now there's moisture problems. People are calling from 3+ hours away, same issue. All along the Gulf Coast, Climate 2A. I understand the push to sell boxes, and I knew that was going on. I don't think I was mentally prepared for the extent of the problem. I sat on the phone with a guy for 30 mins today. Just listening to him describe the exact same moisture problem, throwing tens of thousands at the unit, insulation, attic fans, all the typical attempts. EVERYONE has the same story. It feels like its starting to impact me breaking the bad news. Is it nationwide? Can someone just help me wrap my head around this? Is there any legislation, or code changes coming to possibly stop this? It's exactly what Risinger was describing in that NYT article. Thanks

Hello!
I’m closing on this property in a few weeks located in climate zone 4 (really close to zone 5) and I’m looking at converting this attic space into a conditioned space with a bedroom and bathroom. I am hoping to do that with closed cell spray foam insulation between the true 2x4 rafters. There are currently no soffit vents and just a few whirly bird vents at the ridge and the roof is atleast 11+ years old.

The question:
Should I go to the trouble of installing soffit vents and baffles between the rafters to ensure airflow underneath the roof sheathing? Or should I just have a spray foam company spray the insulation directly to the deck?

I am concerned that if I need to get the roof replaced in the next few years the roofers will damage the spray foam or crack it therefore not making it an air/vapor tight assembly.

I’m also wondering the best way to condition the space, I was thinking a mini split but I am concerned with humidity control. This unit is a rental so I don’t want to have a standard dehumidifier plugged into the wall in the hopes that a future tenant would run it. Are there any other systems I should consider?

Just bought a house in Coastal Georgia with open-cell spray foam directly against the roof decking. Had no clue about the stuff until now. When we bought it, I noticed the decking was visibly cupped/bowed but didn't connect the dots to the spray foam/moisture situation. The decking was also only 1/4" plywood, which made the problem worse.

We just replaced the roof and ended up having to replace 40+ sheets of the 1/4" decking because of the cupping/bowing/deterioration. We went back with the correct/thicker decking. The decking came right off and did not pull any of the spray foam out at all. I was very surprise. There wasn't obvious widespread mold, but the plywood was definitely in bad shape. Very bowed and brittle.

The previous owner apparently had no humidity control in the attic. It was essentially an unconditioned/unvented-uncontrolled spray-foam attic.

I have now added a supply and return to the attic. The attic stays within roughly 10°F of the living space, and current RH is generally 58–65%, depending on time of day. Living-space RH is usually in upper 40’s low 50’s

My main concern is obviously the new roof decking. I don't want to replace 40+ sheets again in 5–10 years after basically for a complete re deck.

### My biggest question:

Is 58–65% attic RH actually safe long-term for the roof deck in an open-cell spray-foam attic in Coastal GA, or should I be targeting something like 50–55%?

I can't seem to find a clear answer anywhere regarding what RH level is considered safe for the roof sheathing in this type of assembly.

I'm considering a dedicated dehumidifier, but that seems like it could substantially eat into the energy savings of the spray foam. My electric bill is already $200+ per month during the summer.

### There may also be an air-sealing issue

I spoke with a reputable local spray-foam contractor and showed him pictures from the roof tear-off. He believes the original installer didn't completely remove/seal the fiberglass batts around the soffit/top-plate area before spraying the foam.

His recommendation was to remove the remaining batts, spray foam that area properly, and completely air seal the perimeter.

My question is: If the only way humid outdoor air is getting into that area is through the soffit vents, could I simply seal the soffit vents? Or is that not an acceptable solution with this type of assembly?

I'd love to remove all the foam and convert the attic back to a properly vented assembly, but that would be a huge project at this point. I've already removed the ceiling batts, and when we did the roof I did not have a ridge vent installed, so I'm probably pretty committed to the unvented/conditioned-attic approach unless I start over.

I've spent the last few weeks researching this and have come across Joe Lstiburek's work on spray foam/moisture and the research/article I've seen referred to as the "ping-pong effect" involving spray foam and moisture. But I still can't find good evidence showing what RH level is actually safe for the roof deck over the long term.

What would you do in my situation?

1. Keep the supply/return and monitor the attic?

2. Add a dedicated dehumidifier and target <55% RH?

3. Address the soffit/top-plate air sealing first?

4. Seal the soffit vents?

I'm mainly concerned with preventing the new roof decking from developing the same moisture-related cupping/bowing problems again, rather than maximizing energy efficiency.

Would especially appreciate input from anyone with experience with open-cell spray foam in Climate Zone 2 or any hot and humid area. Thank you in advance.

We are around 2/3 of the way done building. Our house will be tight.

One extremely simple concept that I never really thought about when we started is the “hidden” costs of tight houses.

If you have a very tight house (probably anything less than 3 ACH 50 but especially less than 1 ACH 50) then you have a lot of extra work to do if you want the house to be comfortable and durable.

• You need to have mechanical ventilation. Most people going into building tight have a general idea of what that means but they probably don’t REALLY know until they’re in the middle of it.

Yes, you can extract air out of bathrooms and kitchen and wherever the most stale air is and then pump the fresh air from the HRV/ERV into the air handler for your house but the air handler does not run all the time. When the air handler is not running the distribution of fresh air in your house will be mediocre which will somewhat defeat the purpose of the mechanical ventilation in the first place.

It’s also true that lots of HRV’s have barely adequate capacity. The Broan 160 AI or whatever it is doesn’t have near as many CFM’s as advertised once you get the ductwork hooked to it. To get adequate air changes per hour you might need a LOT larger ERV budget than you had planned on.

It’s also true that the ductwork for a good ERV setup takes a lot of room. You need to plan the room for this when you’re designing the house if you don’t want to be pulling your hair out as you build.

• you need makeup air for your kitchen hood. It’s a simple concept but implementation to make it effective is not. The simple concept is, “when you pull air out of your house, to prevent a pressure imbalance from inside to outside and to prevent uncontrolled dirty leaks into the house, you really need makeup air to offset the exhaust air”.

People will tell you using a recirculating kitchen hood is the solution for a tight house but any amount of research will tell you it’s not the way to go. You really need to exhaust the bad stuff and then use makeup air to compensate for it. You also want that makeup air to be:

a. from an area outside the house that isn’t near exhaust air so you aren’t bringing crappy air back in

b. filtered so that it’s not filled with pollutants like dust or smoke or whatever may be outside

c. thermally compensated to some degree so that you don’t have to deal with wild temperature swings while you’re cooking

• finally, if you’re going to run a dryer with an exhaust, you need makeup air for it as well.

All of this stuff takes a lot of time to figure out. There aren’t super elegant solutions for them and the solutions that are reasonably good on a performance perspective take a lot of room for ducting and so on.

It ain’t easy…

https://www.cnn.com/2025/05/06/climate/energy-star-trump

It looks like Trump is finishing what he floated back in 2017.

The ENERGY STAR Program (appliances, residential, and commercial) appears to be exiting stage right.

How do you think this will impact your work?

The most improvement for the least money.

So you want to upgrade your house to be more energy efficient, so you can lower your bills, be more comfortable, and use less energy. Maybe even help the environment.

Which items or upgrades should you fix first? What is the most cost-effective use of your money?

Here is my research from several hundred hours of talking to experts and going through the process.

Step 1: Get An Energy Audit

The best way to start is with a home energy inspection and audit from a certified inspector. This will tell you what specific actions to take for your actual house. Your options may vary depending on how old your house is, how it was built, materials used, and many other details.

An audit will likely cost several hundred dollars (say: $400 to $600). But you may be able to find local, city, state, or federal rebates in your area. Even without rebates - accurately knowing what to tackle first could help you to save money and fix the right issues in the long term. It’s worth the investment.

You can also find sources describing how to do your own self-inspections.

Literature Review - What Do The Experts Say?

Here is information I found from surveying experts and existing sources:

1. Book: Pretty Good House

"Between 20% and 25% of a typical home's heat loss [or gain] is from convection as air flows freely through cracks in the building envelope. Preventing these leaks is the cheapest and most cost effective way of reducing heat transfer." --Pretty Good House, Chapter 4

Credentials: Four designers + builders with decades of experience.

2. Book: Renovation

"To be an effective thermal barrier, most insulation must be used with an air barrier that is continuous and contiguous. If air flows through insulation, it's R-values plummet." --Renovation, Michael Litchfield

Credentials: Author of 16 books on home design and renovation; has been renovating houses or writing about them for more than 45 years; founder of Fine Homebuilding magazine.

3. Energy Vanguard Blog

"Don’t insulate your attic until you’ve sealed the air leaks" --blog post

Credentials: PhD building scientist with three decades of experience.

4. Home and Trades Resource Center

"Air-Sealing one’s home is one of the most inexpensive strategies you can employ to help you save money on your utilities and feel more comfortable as soon as it is completed" --The Home and Trades Resource Center

Credentials: Home builder in Alabama with two or three decades of experience.

Their article "Getting the most bang for your buck" starts with air-sealing first, and then attic insulation.

5. Green Building Advisor

Has this lovely article The Energy-Efficiency Pyramid. They suggest doing items in this order:

1. Audit

2. Turn things off

3. Replace lights with LEDs

4. Air sealing

5. Upgrade Appliances

6. Insulation

Credentials: The author, Martin Holladay, is a building science expert who has been building homes since 1974. Chart originally from Minnesota Power Company.

The article is from 2010, and Holladay notes many technologies and efficiencies have changed since then.

6. Energy.gov

"Of the $2,000 the average American spends paying for energy annually, [10% to 20%] could be going to waste from drafts, air leaks around openings, and outdated heating and cooling systems. The potential energy savings from reducing drafts in a home may range from 5% to 30% per year Increasing your home's insulation is one of the fastest and most cost-effective ways to reduce energy waste."

They list air-sealing and insulation as the top two items in their list of most common recommendations. I would count "sealing air ducts" as part of air sealing.

6b. Pacific Northwest National Laboratory

"Air sealing is one of the least expensive and most cost-effective measures you can take to improve your home’s comfort and energy efficiency." --Air Sealing PDF

Note that PNNL is a laboratory run by the US Department of Energy, so this is basically the same source as above.

7. Bob Villa

Insulate, add storm windows, stop drafts. --Bob Villa

Credentials: Host of several home building and improvement shows.

8. Journal Article - Jasmina Burek

"The biggest payoff for both saving money and reducing emissions is weatherizing the home to stop leaks. Insulation can also reduce energy loss. But [unless your home is old, or you get extreme temperatures], it generally doesn’t have as high of a payoff .. as weatherization or window replacement." --The most cost-effective energy efficiency investments

Credentials: Assistant Professor of Engineering, UMass Lowell.

This article seems a bit biased and slanted, but they still list similar suggestions. Their recommendation for upgrading windows before adding insulation seems to differ from other sources. Perhaps that is meant for milder climates. (I live in Climate Zone 7. It gets cold).

9. Energy Company - ‘Sealed’

"Getting updated attic insulation and professional air sealing is one of the primary expert-recommended ways to solve an abundance of energy issues." --8 Best Energy-Efficient Upgrades

From Sealed, a "climate tech" company.

Local Experts: In-Person Discussions

As part of researching and fixing broken parts in my own house, I spoke with multiple experts, including:

• a certified Energy Auditor (national certification)

• a Building Envelope specialist with several decades of experience

• a siding, venting, and sealing expert

• an Attic and Insulation expert and business owner, with several decades of experience

• two master plumbers

• two master HVAC technicians

• multiple window salesemen

• a journeyman carpenter and window installer

All of them either recommended doing air-sealing first before any other updates, or agreed that air-sealing was one of the best, most cost-effective upgrades when asked. Consensus with local experts seems to agree that air-sealing is one of the most helpful actions to improve energy efficiency.

Data from My Home Energy Audit

Here is some real-world data from my own home energy audit.

Part 1: Inspection

I had a certified energy auditor run an inspection on my house. They took a bunch of measurements, noted the model and energy usage of all my appliances, and did a blower fan door test to see how much air was leaking (spoiler: a lot!) Then they used modeling software to calculate all of the different places where my house was using or losing energy, and sent me the results.

Part 2: Collect Quotes

Next came the hard part: slogging through the legwork of finding three competent, reputable contractors for each type of fix, and getting them to come out and inspect my house.

For each different type of upgrade in the inspection report, I got three competitive bids and quotes from different contractors to do the work (always get three bids). As you may imagine - this took months. Some of the contractors were great, and/or came with referrals from people and previous contractors that I trust. With others I was simply shooting blind, and it sometimes took several attempts to find someone who both knew what they were talking about and was also not trying to rip me off.

For general air sealing - this cost is based off my own DIY work doing the air-sealing myself. I spent about $500 on materials such as: plastic poly air vapor barrier, sealing tape, metal foil tape, caulking, spray foam, rigid insulation foam, and other supplies to do the air-sealing myself.

Part 3: Calculate Savings Per Dollar

In the end I got a range of prices for each potential upgrade. I turned this into a spreadsheet, using the average cost (or sometimes the lowest, or actual cost) for each fix.

Here are the cost-savings rows in text form:

  $250 per GJ saved ($0.90 per kWh) - Air Sealing (DIY)
  $425 per GJ saved ($1.53 per kWh) - Attic Insulation (+R40)
  $500 per GJ saved ($1.80 per kWh) - Hot Water Heat Recovery Coil
  $650 per GJ saved ($2.34 per kWh) - Furnace
  $800 per GJ saved ($2.88 per kWh) - Hot Water Heater
$1,500 per GJ saved ($5.40 per kWh) - Windows
$2,500 per GJ saved ($9.00 per kWh) - HRV/ERV
$3,600 per GJ saved ($12.96 per kWh) - Doors

I did the math to figure out the rough cost of (dollars spent) per (amount of energy saved). The chart is sorted by "most cost-effective" at the top, to "least cost-effective" at the bottom.

Notes:

• I did not actually do all of these upgrades. I just wanted to compare and see where I could get the most improvement for my potential dollar.

• I rounded costs and savings in some cases. For some numbers I only had rough estimates.

• I am using a forced-air furnace, powered by natural gas

• I am using a tanked hot water heater, powered by natural gas

• The window comparison was double-pane vs upgrading to triple-pane filled with argon

• Attic insulation is blown-in cellulose

Conclusion: Start With Air Sealing + Insulation

And there you have it! You can see from the chart that the data for my home seems to agree with the suggestions from experts: First do air-sealing to eliminate all of the drafts that you can. Then add insulation.

My current air sealing leakage was rated at 15% of the energy loss for my home, so if you had an "average" home with 20% to 25% leakage as the "Pretty Good House" book suggests, your savings might be even greater.

It is interesting that hot water heat recovery coils may actually be quite cost-effective.

Disclaimers:

• I am in Climate Zone 7, so your results may differ

• You might get different results for your house, depending on how it was built, its current condition, and perhaps your climate zone.

Start by getting an energy audit!

What’s Your Data?

Do you have data, or have you done energy improvements on your home? What was most cost-effective? I would love to hear about it!

References

• Book: "Pretty Good House"

• Book: "Renovation" by Michael Litchfield

• Energy.gov:

  • Energy.gov upgrades

  • Energy.gov Air Sealing Your Home

• Energy Vanguard Blog:

  • Don’t Insulate Until After You Air Seal

  • The 3 Rules of Air-Sealing (seal large, then medium, then small)

  • Wind Washing reducing insulation value

  • 10 Uncommon Tips For Winterizing

• Green Building Advisor:

  • The Energy Efficiency Pyramid

  • Improving old windows: get shades and drapes first

  • Get blinds before replacing windows

• Pacific Northwest National Laboratory (PNNL) - Energy Efficiency Guides - many guides on air sealing

  • PNNL Air Sealing Guide - 40 page pdf

• Drain water heat recovery:

  • energy.gov

  • Berkeley lab report

  • Architect Magazine

• Energy Rates - 35 Upgrades. They don’t seem to sort these in any order.

Great video from ASIRI Designs: Vapor barriers are often required in colder climates to help prevent condensation on the backside of our sheathing, but did you know that a standard polyethylene vapor barrier can actually trap moisture within the assembly? This has led to a lot of mold and rot remediations, as our buildings need the ability to dry if they get wet. Buildings can get wet from rainwater penetration, plumbing leaks, capillary transfer of water, and air leaks, and we need to allow this moisture to be able to dry out. This is where we recommend making a shift to smart vapor retarder membranes instead of the standard polyethylene. Smart vapor retarder membranes increase in permeance when conditions are damp or humid, preventing moisture from being trapped within the assembly.

We try to tighten our houses as much as possible but then there are range hoods, dryer exhaust and bathroom fans which are basically big gaping holes and ruin all the efforts.

Am I missing anything or are these really a disaster for air leakage?

Do they have some fancy way to seal the hole when turned off (like a backflow flap) and it only opens when in use?

At least around me (Zone 5A, Pennsylvania), walls need to have a air/vapor barrier (tyvek, taped zip, etc). As far as I know, ceilings construction is usually: drywall as an air barrier (typically a poor job done here), insulation, vented attic, roof. No vapor barrier in there! Shouldn't condensation be forming inside the insulation layer?

So I have a 90s house in zone 3A- and every time I talk to a contractor its like I have 5 heads. Try to talk Air quality with an HVAC shop? pfft. Ask about air sealing with a modern WRB when getting a siding quote? Most flat refuse and the only one who will entertain the idea demands a waiver if anything goes wrong. I'm just an interested homeowner, I should be able to ask questions, not completely befuddle your guys based on Build Show, Fine Homebuilding, and Green Home articles...

Follow on question: To retrofit my 3A 90s house with modern air sealing, how do I prevent sun driven outdoor moisture going into the drywall on the inside of the wall cavity? My understanding is moisture will "want" to go from high to low temperature and humidity locations- so from outside 80 degrees and 80% humidity towards my interior that's 67 and ~50% humidity.

Why is there a hot square in the ceiling beside this supply duct in master bathroom? The geometric shape (square) makes me think it almost has to be the heat signature is the result of something mechanical - not the result of envelope/insulation/thermal boundary deficiencies. Residence is located in the southern part of south Florida.