Insulation in basement to keep 1st floor Warmer?

Alan_Koziol

Morning everyone,

I realize the title may sound like a stupid question, but there is more logistics behind it and I'm not sure how it would turn out.

What I can tell you about the basement (Facts).
1. Fieldstone foundation.
2. Concrete floor.
3. Ceiling area is all opened up (You look up you see the 1st floor joists).
4. It is a low ceiling area (Maybe slightly over 6', not including the area of the joists).
5. The piping for my heat zones (FHW) starts at the boiler along the joists then becomes perimeter piping (Loops around my basement).
6. Some of my electrical runs in the same fashion.
7. I have the heating pipes wrapped (try to prevent as much heat loss when zone runs).

With all that said: Would I benefit by putting insulation in the joist cavities? OR Am I creating a whole new problem in the process?

Thank You

Jamie Hall

I wouldn't put insulation in the joist cavities -- let them breathe. What I would do (and have done on several similar buildings) is to go around the edges and seal up as many of the openings to the great out of doors that I could find. A windy day is great for this. There are a variety of nice expanding closed cell foams in cans... they work fine, but you'll need more than one can!

EBEBRATT-Ed

With a fieldstone foundation i would't insulate it yet. It makes and excellent hiding place for mice. if you can get the foundation sealed then maybe. You could probably use that bubble wrap insulation pushed up to the subfloor

Robert_25

That is not a stupid question. I agree with Jamie - focus on sealing up the air leaks.

I would also talk to a spray foam insulation contactor about having the rim joist insulated. Do not just pack fiberglass insulation up against the rim joist - it can cause moisture issues.

Once you get the basement tightened up you should see that it stays considerably warmer in cold weather.

JakeCK

Not only is a windy day a good day to find leaks but if it is really cold its pretty easy to find every little hole too. 

Also look for any openings going up into the structure to slow losses from the stack effect. Any penetrations for plumbing, wires, and such. Also check around interior chimneys and any large chases. For example I have a large interior chimney and laundry chute I could shine a flash light down between the basement and attic. Also I have a wet wall that runs that distance as well that is used for the main stack and drain vents. Any large holes you might want to buy a sheet of foamboard and cut pieces to fit and seal around. Anything that could be used as a fire path you'll want to block with solid wood too and fire rated foam.

Someone mentioned doing the rim joists in spray foam. Be warned that it is insanely expensive right now. Ever since the texas freeze last winter the petrochemical industry has been disrupted. Get a quote and your eye balls will float around in your head. Another option is to use foam board and canned foam for the rim joists. There are also spray foam kits you can buy like dow chemicals froth-pak. Although you have to be real careful to make sure the two part foam mixes correctly and that the temperatures of both the tanks, surface being applied too and room are correct or you will end up with a smelly mess.

pecmsg

This is one of the few times an Infra red Thermometer can be useful. If you don't mind spending the bucks a Flir Camera is really good.

PC7060

JakeCK said:

Someone mentioned doing the rim joists in spray foam. Be warned that it is insanely expensive right now.

I ran into this too. 1200 sft addition with foamed 2x6 wall and foamed roof; $4500 last year.  Talked with sales guy recently and said price now would be over $10k. 

PC7060

Agree with sealing up the gaps and holes.  Buy the pro foam can from lowes and Home Depot that attach to the screw on guns similar one posted below.  The pro can last long time and the long feed tube make it easy to get into the nooks and crannies. 

Foamnseal FNS 500 Polyurethane Foam Dispensing Gun / Tool https://www.amazon.com/dp/B00F2ZGTJE/ref=cm_sw_r_cp_api_glt_fabc_MJ45DCPZYHW6R6VWW606

JakeCK

PC7060 said:

JakeCK said:

Someone mentioned doing the rim joists in spray foam. Be warned that it is insanely expensive right now.

I ran into this too. 1200 sft addition with foamed 2x6 wall and foamed roof; $4500 last year.  Talked with sales guy recently and said price now would be over $10k. 

Don't ask what the quote was for foaming my attic rafters and gable ends... I was thinking of bringing my walkup attic into the building envelope. At over 5 figures I'd probably be retired before it paid its self off.

pecmsg said:

This is one of the few times an Infra red Thermometer can be useful. If you don't mind spending the bucks a Flir Camera is really good.

Flir also makes a thermal camera that attaches to cell phones. Not nearly as good as a professional camera but it does a darn good job spoting cold/hot spots in a building.

The wife was supposed to get me one for fathers day.

Alan_Koziol

The joys of an old house..... NOT.

But Thank You for all of the feedback and suggestions. Gives me some food for thought and what possible options I have.

Once again... Thanks

NoelAnderson

Does anyone have an opinion on using Rockwool/Mineral wool in the joist cavities instead of foam or fiberglass?

Jamie Hall

NoelAnderson said:

Does anyone have an opinion on using Rockwool/Mineral wool in the joist cavities instead of foam or fiberglass?

I do Very unfavourable, unless you can find a way to keep it absolutely dry and keep the mice and other critters out of it. And good luck with that...

JakeCK

Jamie Hall said:

NoelAnderson said:

Does anyone have an opinion on using Rockwool/Mineral wool in the joist cavities instead of foam or fiberglass?

I do Very unfavourable, unless you can find a way to keep it absolutely dry and keep the mice and other critters out of it. And good luck with that...

I've found my felines to be very effective at rodent control.

Jamie Hall

JakeCK said:

Jamie Hall said:

NoelAnderson said:

Does anyone have an opinion on using Rockwool/Mineral wool in the joist cavities instead of foam or fiberglass?

I do Very unfavourable, unless you can find a way to keep it absolutely dry and keep the mice and other critters out of it. And good luck with that...

I've found my felines to be very effective at rodent control.

That's the theory. Mine make friends with the little beggars instead.

neilc

so as an aside,
why the drastic increase in foam pricing?

Jamie Hall

Not rocket science -- the foam is made from oil... and the price of oil has doubled since January...

JakeCK

And not only has oil doubled but when texas froze last year it damaged a lot of their petrochemical facilities. While all of that should have been long repaired and brought back online it just caused a cascade effect though the market. Like everything else that has gone sideways the past year and a half.

psb75

I was told that there was one extremely large resin plant in TX that "froze up and broke." It made resin for pvc, Uponor black fittings, red and blue resin for pex pipe etc. Spray foam may have a resin component.

hot_rod

Expensive is a relative term, sounds like energy costs are going up also.
Insulation is the gift that keeps on giving😃

A blower door test would indicate where you have infiltration issues. Spray cans of foam go a long way for sealing cracks. Once the cracks are sealed and wind and moisture kept out, then batts could be used.

Most blower door software can put a $$ amount to the energy loss in the openings it detects.

If budget allowed, I’d spray foam the entire foundation, joist bay ends.

Many  areas have energy audit programs, some at no charge from the utilities, check www.dsireusa.org
to see what is available in your location

psb75

The priority scheme is:
1.) air seal
2.) insulate.
...in that order.

psb75

Spray foam can actually air seal AND insulate-- in one go. Two fer one! $$

JakeCK

dense pack cellulose can air seal as well if done right. But that applies to foam as well.

Alan_Koziol

Never 2nd guess yourself LOL. I went down my basement to verify what everyone has been saying. The perimeter is sealed with spray foam.

hot_rod

The most common method is an inch of spray foam just to air seal, then as much batt or cellulose as the space will allow.  Foam is just too expensive now to fill joist or stud spaces. That rim joist area should have 10” or so.

REDD

Moisture rises into a building through a basement concrete floor (Below grade). If the building is sitting in a dry location, then not so much a problem. In any event, blocking moisture within the basement (Insulating the ceiling joists), you will raise it's moisture content making it damper and colder. Heat loss is above or through side walls and generally a cold mass stays low (Those in HVAC know?!). Having Radiant heat below a concrete floor has taught me a big lesson. It dries out the concrete and really makes a difference for a basement. As I type this, I am sitting above such a floor, below grade, in November, in the north. Forced air here would make my location less comfortable and I would not be sitting down here in winter for sure! The house is 55 years old.