R30 overkill down south?

[1Admin]

Have an old house on the property I've been slowly working on over the years.

Looking at insulating the floor, it's a crawlspace type deal.

Is R30 overkill for southern Georgia?

We have seen snow a couple times in the 12 years we've been here. Once it stayed for most of the day LOL.

The $$ difference isn't that great between that and R19 but it's enough to question.

Thoughts on this? TIA

[Rmplstlskn]

Have an old house on the property I've been slowly working on over the years.

I'd say OLD HOUSE are the key words there, as most issues with old houses is AIR INFILTRATION and leakage... With a leaky old house, I'd say R30 is not overboard, but spray foam and high R-value attic insulation would be a good place to place that extra money instead... When in Florida, the biggest problem was the brutal temps from the sun hitting the roof, heating the attic, then leaking into the house, forcing more AC useage. Also heat from the windows and walls into the home. If the floor is a crawl space or enclosed, I'd say that is the least of the insulation worries...

Then I'd say consider your windows & doors... Old windows and doors are terrible insulators and leak all over the place...

[610Alpha]

I'm with rmplstlskn on this, spray foam the cracks and use R19. Your best bet is to seal your windows, doors, and good insulation in the attic. The key for you is to keep the attic well insulated and ventilated (IMO) for your climate. You might also make sure the perimeter of the crawlspace is insulated, run the numbers.

Do you know how soon the pay off is for R19 vs R30? Will you see a diff in your electricity usage (not sure if you are totally off grid) for running the AC (I don't think you use much heat)?

[HDM]

Finally a subject that I know a little about. For once I can contribute instead of just learning from all of you. I have been in construction for nearly forty years and I am in Georgia. Insulation is a cheap way to save money. Especially as you said the difference between R-19 & R-30 is not that much. Insulation is one of those things that it truly is the more the better for the most part. You would have to go crazy to really be in overkill territory. The biggest savings would be in the summer, keeping the cool air from falling through the floor as fast.
That's my two cents worth, that in today's economy is worth about zero now.;)

[610Alpha]

That's my two cents worth, that in today's economy is worth about zero now.;)

Is that due to inflation or deflation?? LOL.

Excellent point! I was kind thinking that keeping it cool would be the bigger benefit but didn't articulate it.

[ANVIL]

On the plus side an old house bulit befor AC, may of been bulit to make the bestuse of any breez to help with cooling. High cealings and windows that you can walk out of.

[dilli]

the extra paid for spray foam is not worth it !! go with the 30 if it is not much difference in price.. from the manthing, doing insulation for 25 years

[1Admin]

Thanks Dilli. Was hoping you'd chime in on this. I remembered that he did insulation. Tell him hello and thanks from me.

[Rmplstlskn]

the extra paid for spray foam is not worth it !! go with the 30 if it is not much difference in price.. from the manthing, doing insulation for 25 years

R30 is the best value, but R30 will do little to seal up gaps, spaces and air infiltration that most old homes have...

My old home (1944) has rough cut floor joists that vary in spacing width in many places, usually by an inch or two. So this makes the 23" rolls too loose in many places, leaving gaps on each side of the insulation rolls that are uninsulated. Add in the old-school wiring, plumbing and boiler water lines under there and it is an insulation headache. I can't wait till I can afford to pull all that insulation out, lay down a good SEALING layer of spray foam, especially along the perimeter of the house. Then I can insulate the CRAWL SPACE rather than the floor. Insulated crawl spaces is where the research is taking us after much testing...

[HDM]

R30 is the best value, but R30 will do little to seal up gaps, spaces and air infiltration that most old homes have...

My old home (1944) has rough cut floor joists that vary in spacing width in many places, usually by an inch or two. So this makes the 23" rolls too loose in many places, leaving gaps on each side of the insulation rolls that are uninsulated. Add in the old-school wiring, plumbing and boiler water lines under there and it is an insulation headache. I can't wait till I can afford to pull all that insulation out, lay down a good SEALING layer of spray foam, especially along the perimeter of the house. Then I can insulate the CRAWL SPACE rather than the floor. Insulated crawl spaces is where the research is taking us after much testing...

Exactly right. The latest building trend is to enclose the crawl space and the attic with insulation instead of insulating the floor and ceiling.

[1Admin]

Can you explain that further.

[dilli]

yes you both are correct but to do such is very costly. Hubby does this day in and day out so unless you have lots of throw away money it is out of reach for most folks. If I could tell you the number of complaints that the company gets after said encapsulation people would be very surprised given that it is so expensive. I insulated along side the hubby for many years I know what old homes are like and crawls, its where i spent most of my time .. he did high stuff i did low cuz I am short. ... yes older homes are a pain but there are ways around it

[HDM]

Hey Dilli, Thanks for the info. I knew that encapsulation was the latest trend but I have not done a house like that and did not realize that the cost difference was that great. Can you give me an idea of the cost difference and what makes it so costly?

[dilli]

the plastic to encapsulate is something like 30 mil or something crazy so it makes it very expensive. Then the tape used to tape the plastic is also quite pricey... its also rather labor intensive in comparison to just using batts to do it. I am not positive on price difference on the foam versus batts but will ask the manthing this evening to give ya an idea.. i do know the company will not do any job involving the spray foam for under a grand

[dilli]

the ol feller says it is about 10 times the price to encapsulate and spray foam. They also recently at least in commercial jobs began mandating fire proof spraying too. he does not know if it is for all new builds or not but if it is that will further jump the price difference.. in a new build or if you just have funny money to throw around it is nice but for most the spray and encapsulate is outta the price range..