Spray foaming the attic

[ballsdeeeeeep 9]

30 year old house.  Its super inefficient.  Going up into the attic is almost death during the summer.  Ac struggles to keep the areas of the house cool that are not protected by a second floor.  Buddy has a new construction house and his foam sealed attic peaks at 90 degrees right now allowing everything to be more efficient.  Is it possible in a spray foam retrofit to get good results or is it basically only a thing for new construction. 

Anybody on this site install this stuff or has anybody personally done it and can talk about the results?

 

Thanks

[RPM 26316]

I sprayed 2 inches of foam on the walls and ceiling of my garage/shop. I can definitely tell the difference, especially in the winter. But, it's all metal. Not sure what spraying over old wood would do. 

[Parliament 14239]

Do you have insulation in the ceiling of your 2nd floor (ie a "hot attic)"? If so, spray foam won't help much.  

If you have your AC unit and ducts in a hot attic, it loses a LOT of cold up there.  Take a look at all of that.  Austinite Matt Risinger has some good stuff on this.

https://www.youtube.com/c/MattRisinger/search?query=conditioned attic

 

In your case it would be a retrofit and I have no idea the cost of that.

[fattyflattie 4639]

Damn, that vid makes me jealous of that attic. Subscribed. 

[Post Oak 20206]

You don't want spray foam directly touching the underside of the roof decking. It doesn't let the roof breathe and ages the roof much faster.  

Looked at a house that had this and thought great.  The roofer came out and said the roof looked twice as old as it was.  I think it was a 10-year-old roof but I looked closer to 20.  

I don't know how much that matters in the long run  because of the chance of bad storms causing a roof to need to be replaced.

We didn't end up offering on the house for other reasons but it was a concern.

 

Whoever you get to do it needs to know what they're doing.  I'm not sure of what that looks like but I would definitely ask.

[deadshank 24652]

Spray foam (closed cell or open cell, closed cell is most common) insulation needs to be done on underside of roof deck (won’t prematurely “age” a roof - that was some roofer trying to sell a roof) and on all exterior walls.  
 

Spray foam application to an entire house means you need to seal all openings around doors and windows, can (recessed) lights, and any other similar opening that could pose an air leak, have a mechanism for make up / fresh air intake that works in a manner  to ensure your house has positive (“outgoing”) pressure.  
 

All soffit vents and gable end vents (intake) are sealed and all ridge vents, wind turbines and electric attic exhaust vents are removed.  You have to spray the back side of the wall sheathing, as well. You now have a sealed house.  
 

Simply applying spray foam to the bottom of the roof deck will seal all of your exhaust while your intake (humid air) remains unchecked and your house becomes over humid and is now wrecked. 
 

Check the insulation (batt or blown-in loose fiberglass) above your ceilings. Remember, you are insulating your conditioned air space (all “inside the drywall”) and not trying to insulate the non-conditioned air spaces.  

Further, make sure your HVAC ducting is intact and not leaking.  
 

A radiant barrier may help, as well.  
 

 

[UT_OB1 2217]

On 6/18/2022 at 12:15 PM, deadshank said:

Spray foam (closed cell or open cell, closed cell is most common) insulation needs to be done on underside of roof deck (won’t prematurely “age” a roof - that was some roofer trying to sell a roof) and on all exterior walls.  
 

Spray foam application to an entire house means you need to seal all openings around doors and windows, can (recessed) lights, and any other similar opening that could pose an air leak, have a mechanism for make up / fresh air intake that works in a manner  to ensure your house has positive (“outgoing”) pressure.  
 

All soffit vents and gable end vents (intake) are sealed and all ridge vents, wind turbines and electric attic exhaust vents are removed.  You have to spray the back side of the wall sheathing, as well. You now have a sealed house.  
 

Simply applying spray foam to the bottom of the roof deck will seal all of your exhaust while your intake (humid air) remains unchecked and your house becomes over humid and is now wrecked. 
 

Check the insulation (batt or blown-in loose fiberglass) above your ceilings. Remember, you are insulating your conditioned air space (all “inside the drywall”) and not trying to insulate the non-conditioned air spaces.  

Further, make sure your HVAC ducting is intact and not leaking.  
 

A radiant barrier may help, as well.  
 

 

I have a single story house with 2 car garage. The attic is continuous, so it includes the garage. They didn’t put any insulation over the corner of the attic that is above the garage. In my head that seems mostly ok since we’re only trying to insulate the conditioned part, as you mentioned, but I could also talk myself in to that being then reason the back rooms that have an interior wall that touches the garage are hotter. Worth insulating that section or do I have a different problem 

Edited June 20, 2022 by UT_OB1

[deadshank 24652]

Insulate the walls between the garage and the back rooms.   You could build a wall in your attic that blocks off the area above the uninsulated garage and insulate that wall.  Now the garage is completely separated for the rest of the house.  Don’t insulate the garage exterior walls or the garage ceiling. 
 

That may be uncommon but I’ve seen it done before where the conditioned air house is spray foam and the garage is not (because it is not AC’d.  Partition walls where built and insulated. 
 

Same concept. 

[ballsdeeeeeep 9]

I'm pulling the trigger to retrofit my house.  The breakeven will be when I die so financially its a shit move.  I'll try to report back drop in kw useage in the future so you guys have some data.  Pie in the sky salesman says I should drop about 50%.

My buddy has a very similar footprint from me and sprayed the entire house.  His kw useage is 17000 annually.  Mine is 41000.  Fuck. 

[drt 638]

You must have a big ass house and pool. 

[ballsdeeeeeep 9]

Also, it will be pain to run wires through external walls after this so I'm doing a bunch of shit to prepare for that.  Anything that I should go ahead and run that you guys can think I'm missing.  Subpanel for Evs is going in the garage.  Some other random electrical shit I've been wanting.  Anything yall can think of i should address.  Thanks

[bobcat1995 71]

I am going to do my best to explain this so i apologize if my description isn't clear. 

We have a media room on the second floor.  The room has no walls that connect to the exterior of the house.  The media room sits right above the 3 car garage and I can access the backside of 3 walls from the attic.  The walls currently have the pink insulation in between the wall studs.  The garages face west and get full sun.  this time of year the second floor gets really warm and doesn't cool down until after 10pm.  It was 81 degrees last night at 9:45p.   

Can I add attic foil to the backsides of the walls to help reduce the heat on the second floor?

Should I remove the insulation and spray foam the walls?  Again, I have access to the backside of the walls from the attic.

 

DFW area

[deadshank 24652]

18 hours ago, bobcat1995 said:

I am going to do my best to explain this so i apologize if my description isn't clear. 

We have a media room on the second floor.  The room has no walls that connect to the exterior of the house.  The media room sits right above the 3 car garage and I can access the backside of 3 walls from the attic.  The walls currently have the pink insulation in between the wall studs.  The garages face west and get full sun.  this time of year the second floor gets really warm and doesn't cool down until after 10pm.  It was 81 degrees last night at 9:45p.   

Can I add attic foil to the backsides of the walls to help reduce the heat on the second floor?

Should I remove the insulation and spray foam the walls?  Again, I have access to the backside of the walls from the attic.

 

DFW area

You need to get the heated air out of your garage.  

[Post Oak 20206]

Keep us updated @ballsdeeeeeep.  I'm interested in following your progress.

[luke duke 6412]

Is your garage door insulated?

[Catpfish 618]

I was told not to do any spray foam at all above the garage as the idea is to completely seal off air flow. You have no way to deal with car exhaust and carbon monoxide getting in the foamed areas.

[Jiggy-Z 3432]

I used to have small spray foam business. Quit because I hate sales and people.

Great product though.  Payback is about 5 years on a typical tract home retrofit -roof only.

Current home(4000 sqft) is spray foamed  haven't had a bill over $300 ever.

[Catpfish 618]

11 hours ago, Jiggy-Z said:

I used to have small spray foam business. Quit because I hate sales and people.

Great product though.  Payback is about 5 years on a typical tract home retrofit -roof only.

Current home(4000 sqft) is spray foamed  haven't had a bill over $300 ever.

Wish I could say the same.  3400 square feet and electric bill was $399 last month.  Of course, we have a ton of windows, are at the top of hill, no trees to shade the house and a pool...but, still.  I'd hate to see the bills without the foam. 

[Post Oak 20206]

Has anyone tried using window film?  I have two big windows that get the PM sun and I've looked into trying something until my oaks can grow.

[ballsdeeeeeep 9]

@Catpfish Couple of questions that hopefully you can help address.  I have had two spray foam installers at the house and one is saying I need to swap out my furnaces and water heater to closed combustion systems.  The other one says its fine.  I would rather not blow up my house but if i can avoid a huge bill by keeping my existing equipment that would be great.  What did you recommend when you were doing installs. 

Anybody have good recommendations for the following trades in the Houston area.  I'm currently lining up bids for the furnaces to be swapped and the water heaters (plumber quote was outrageous) to be be updated.

Electrician - need to add a panel next to my existing panel (out of circuits)

Plumber - tankless water heater

Hvac - swap out furnaces.  Anybody have experience with a straight electric furnace? 

[Catpfish 618]

2 hours ago, ballsdeeeeeep said:

@Catpfish Couple of questions that hopefully you can help address.  I have had two spray foam installers at the house and one is saying I need to swap out my furnaces and water heater to closed combustion systems.  The other one says its fine.  I would rather not blow up my house but if i can avoid a huge bill by keeping my existing equipment that would be great.  What did you recommend when you were doing installs. 

Anybody have good recommendations for the following trades in the Houston area.  I'm currently lining up bids for the furnaces to be swapped and the water heaters (plumber quote was outrageous) to be be updated.

Electrician - need to add a panel next to my existing panel (out of circuits)

Plumber - tankless water heater

Hvac - swap out furnaces.  Anybody have experience with a straight electric furnace? 

BD, not an installer, just built a house with the spray foam from the start (even spray foamed some interior walls for sound deadening).  My house is all electric so I didn't have to worry about gas appliances and the possible buildup of fumes.  I was actually not aware that you could put gas appliances in a foam house when I first started planning (about 9 years ago), so I always planned on all electric.  I would be leery of not switching out the units.  My understanding now is that the gas units should be enclosed and completely sealed off with outside venting to prevent the gases from getting back into the house, since the whole purpose of the foam is an airtight seal.

I can tell you that the house is pretty airtight.  We have to crack a nearby window to get a fire started, otherwise it'll barely smolder.  Once it's going, it creates a draft with a separate fresh air inlet specifically for the fireplace only.  

 

[ROFL BOX 6647]

1.  Deadshank is 100% correct in that the statement of "closed attics void your warranty" is bullshit.  It is quite possible your roof was aged before you bought the place.  Photo of house?  A proper closed attic insulation system is actually BENEFICIAL to your shingle warranty as it will prevent expansion / contraction which can crack or craze your shingles.

 

2.  Be very careful about the roof installation because I have in the past 5 years had 3 houses (1 metal, 2 shingles) where I could not diagnose what the point of fail was for a leak.  The foam will hold the water & it ends up showing an interior leak in a place that is alien to the actual penetration.

[ballsdeeeeeep 9]

4 hours ago, ballsdeeeeeep said:

@Catpfish Couple of questions that hopefully you can help address.  I have had two spray foam installers at the house and one is saying I need to swap out my furnaces and water heater to closed combustion systems.  The other one says its fine.  I would rather not blow up my house but if i can avoid a huge bill by keeping my existing equipment that would be great.  What did you recommend when you were doing installs. 

Anybody have good recommendations for the following trades in the Houston area.  I'm currently lining up bids for the furnaces to be swapped and the water heaters (plumber quote was outrageous) to be be updated.

Electrician - need to add a panel next to my existing panel (out of circuits)

Plumber - tankless water heater

Hvac - swap out furnaces.  Anybody have experience with a straight electric furnace? 

apologies.  meant this for @Jiggy-Z

[Jiggy-Z 3432]

5 hours ago, ballsdeeeeeep said:

@Catpfish Couple of questions that hopefully you can help address.  I have had two spray foam installers at the house and one is saying I need to swap out my furnaces and water heater to closed combustion systems.  The other one says its fine.  I would rather not blow up my house but if i can avoid a huge bill by keeping my existing equipment that would be great.  What did you recommend when you were doing installs. 

Anybody have good recommendations for the following trades in the Houston area.  I'm currently lining up bids for the furnaces to be swapped and the water heaters (plumber quote was outrageous) to be be updated.

Electrician - need to add a panel next to my existing panel (out of circuits)

Plumber - tankless water heater

Hvac - swap out furnaces.  Anybody have experience with a straight electric furnace? 

All my guys are in Austin.

[drt 638]

Also in Austin, but would absolutely recommend swapping units to sealed combustion.  Carbon Monoxide is not to be fucked with.

[deadshank 24652]

On 6/27/2022 at 12:00 PM, Catpfish said:

 

I can tell you that the house is pretty airtight.  We have to crack a nearby window to get a fire started, otherwise it'll barely smolder.  Once it's going, it creates a draft with a separate fresh air inlet specifically for the fireplace only.  

 

This right here.  Special mechanical venting at fireplaces (especially wood burners).  
 

If your are building and want spray foam you’d best have a very good HVAC and fireplace contractor to go along with your insulation contractor.   Also, budget for private inspection fees for reviewing subcontractor work and meeting city code and industry standards. 

[CTC2 2791]

My attic is just like the one in the video.  Yes, it is true.  Yes, it is very nice.

[ballsdeeeeeep 9]

Started getting quotes from the various trades to get the attic project moving. 

Plumber:  Install a tankless on the side of the house.  2000 for the heater.  5000 for labor. 

Electrician:  Update the main panel and install a sub on the other side of the house.  20,000

Hvac:  12k to swap out two systems.  This one felt reasonable. 

The trades are still crushing it right now. 

The project is delayed now.  I am grumpy enough to save 5k on the water heater and make the 3 connections myself.  Same with the electrical to save 20k.  It will be just a lot slower for me to do it myself.  I aint crawling in a million degree attic. 

I will hopefully knock all this out in the fall. 

[Parliament 14239]

What are you doing in the attic for insulation?

 

[ballsdeeeeeep 9]

attic floor is the blown in insulation