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peethree 10-16-2005 05:33 PM

Spray foam insulating joists in basement?
Hi, I have received a quote for upgrading insulation in my home (I am a limited DIY-er and this is not something I plan to do myself)

House is 19 yrs old, 2 story brick structure approx. 3100 sq ft, unfinished basement near Toronto, ON

We have no plans to finish the basement in the next 4-5 years. There is currently yellow batt insulation framed in halfway down the walls.

The contractor is recommending that we insulate only the basement "headers" (his terminology) with 2 component spray foam insulation. He will then cover the foam with R12 fibre glass batts and install vapour barriers onto the headers.

To clarify, this is the area at the very top of the basement walls, in between each joist supporting my main floor, all the way around the full perimeter of the basement

He says this will make far more difference then finishing the insulation down the other half of the walls.

Can I please get some additional opinions on this?

Thanks in advance,

'Andyman 10-17-2005 10:06 AM

Basement Insulation

I can't imagine why he wants to spray foam AND use batt insulation. Unless you can feel drafts at the sill plate where the joists sit. If so, this could be caulked and then the R12 batts could be placed between the joists. Doing it this way, any DIYer could do it. I have batt insulation in mine. As far as taking the existing wall insulation down to the floor, there is no great need for that as the building code requirement only calls for insulation down to the frost line in the ground outside. Should you finish your basement, it is worth the extra to add the extra insulation and of course, a floor to joist vapour barrier

peethree 10-17-2005 10:20 AM

basement insulation
Hi Andyman

Thanks for your reply. There is already yellow batt insulation there - he was going to remove it, then do his thing with the foam and new batt....hence my puzzlement.

See, where this all began is that we have had really high energy bills and wanted to look at ways to conserve energy...esp. since I work at home so our energy use is higher than the average bear anyway.

I had an EnerGuide for Houses audit done and they recommended several improvements, including:

Attic: current = R15, increase to R50 to save 6% on energy costs (I've since heard from several sources that you need not go above R40 - so I'm getting quotes for blown-in cellulose to get me up to R40)

Basement: current = R1, increase to R20 to save 12% - having a heck of a time finding someone to even call me back about installing insulation - I guess everyone is so busy with new home construction :)
- and then this fellow said don't bother insulating down the walls, just do the top as per my original post

Space heating: current low efficiency, change gas heater to high efficiency to save 30%

...and then misc. things like caulking, etc.

I'm starting to wonder, should I just skip the basement and focus on my attic and getting a new heater, caulking etc., then worry about insulating my basement further when we get around to actually doing any finishing / renos in the basement?

And how can I tell what the R-value of the current batt is? (I suspect we got an R1 rating because the basement walls are only half finished)

Thanks again

'Andyman 10-17-2005 01:25 PM


Not a bad idea to start at the attic as that could be the biggest source of heat loss. Blowing in is obviously the fastest way to go, but depending on the estimate, and if you are reasonably fit and nimble, batt insulation comes precut to fit in between joists and it is just a matter of getting up there and laying it in place. Just dont compress it as it loses it's efficiency. The batts are marked on the paper backing with the R value. Caulking where necessary is also a big plus for energy conservation. Replace the batts at the basement joists also for a greater R value. Even switch plates and receptacle covers on outside walls can be fitted with small gaskets behind as sometimes a draft can originate there also. I cant comment on the space heater as I've never used one. No question, good insulation, caulking, have kept my bills surprisingly bearable in a somewhat smaller 2400 sq. ft. house.

peethree 10-17-2005 01:37 PM

Basement insulation
Hi Andyman,

Thanks again! We'll continue with our homework and also look at doing the attic ourselves.

(quote)Caulking where necessary is also a big plus for energy conservation.
-- yup, I've started that already and am making my way through the house inside and out. Next up is weatherstripping!

(quote)Even switch plates and receptacle covers on outside walls can be fitted with small gaskets behind as sometimes a draft can originate there also.
-- yup, already have done that too (including plug covers for the unused outlets)

(quote) I cant comment on the space heater as I've never used one.
--sorry, that's the Energuide terminology - it's referring to the furnace :)

I also have found that putting plastic film on some of my windows during the winter months can really make a difference and would recommend this to other readers - it's not that hard to do (even an amateur DIY'er like me!)

Thanks again for all your help!

spotofbother2 08-20-2007 04:46 PM

icynene versus icylene
Could someone tell me the difference between icynene and icylene. they are both listed in the yellow pages in my area.

I have a fieldstone unfinished basement. Can it be insulated by simply applying spray insulation to the surface? What preparation is required?

adriand 08-24-2007 07:21 AM


I'm planning to do the spray foam insulation in the headers as well. I do notice a lot of drafts coming through the sill plate area in the winter.

I have existing batt insulation in the cavities but its clear that spray foam would do a much better job of sealing every point of entry . Especially where the headers are parallel to the foundation wall. This space would be easy to fill with spray foam.

As for the roof insulation, make sure the contractor puts "morvents" or similiar on the underside of the roof decking. These vents prevent the new cellulose insulation from blocking the passage of air at the eaves and preserve your ventilation. This is important to prevent moisture buildup in the roof.

Make sure your bathroom vents are hooked up to roof vents with metal duct too before you put the cellulose. Once its in you wont be able to access anything in the roof area easily. You dont want mould growing up there.

Yazzy 11-25-2010 04:36 PM

Spray foaming basement joists
I have been doing alot of web research on this; here is the best, most logical information I have collected. Firstly, paste this: in your web browser and read it all carefully. It is from an engineer with a background in thermodynamics. Pay particular attention to pages 9-13 and Figures 11 (your best option currently), 13, and 14 (your best and healthiest future options). Note that a vapour barrier is NEVER used. Also, here is a cheap and money saving DIY project. In the basement, on the side of the cold air return near your furnace, there should be a 4"-6" diameter hole with a damper. If no hole is present, make one; it can be square or round (harder to cut) depending on the type of take-off you will install in this hole. Using the proper size hose clamp, securely connect the shortest length of flexible dryer vent (either plastic or metal) that will rest horizontally on the floor with as few bends as possible. Less bends equals less resistance therefore greater air flow. This will suck the coldest air in your house up. Be sure to set your furnace fan to AUTO during the heating season, and ON/CONTINUOUS 24/7 during the cooling season. Also, any ceiling fans (the more you have the better) should only blow DOWN and run 24/7 all year long.
Now the attic; this is where you get the "best bang for your buck" because the greatest heat transfer occurs here (heat loss in winter, heat gain in summer). If your attic is between R-12 and R-25 at your 1st energy audit you will get $250 Ontario Gov. Rebate by improving to R-40, and $375 by reaching R-50. Make sure you have enough (and you can NEVER have too much!) attic ventilation at both the soffits (air comes in; use foam channels) and on the roof (air goes out; use ridge venting). Electrical switch plate and receptacle gaskets on exterior walls and proper exterior and interior caulking are also cheap to do yet very effective. Hope all this helps. Good Luck.:thumbsup:
Don't Forget To Protect Any Polystyrene Foam From Fire By Using 5/8 Inch Thick Drywall!! It's the toxic smoke that this foam gives off during a fire that will kill you!!! :furious:

SPS-1 11-25-2010 05:27 PM


Originally Posted by peethree (Post 5189)
I've since heard from several sources that you need not go above R40

That is correct you don't have to go above R40. But then again you don't have to go above R15. R40 is the current Ontario building code requirement for attic insulation on a new home. But you have to understand that the building code does not define the "best" practice. It defines the minimum acceptable practice. In other words, anything less than R40 is so crappy that its illegal.

I have R70 in my attic, and I'm in the banana belt in Windsor.

Yazzy 11-25-2010 06:12 PM

I forgot to mention, go to (or phone toll free 1-866-467-7729...1-866 GO SPRAY) for more information about foam insulation in general and a list of licensed contractors. Read the Mission Statement and the Quality Assurance Program details that CUFCA members must adhere to. If your contractor is not a member, ask why. For me personally it provides peace of mind. BTW every job is different and has its own unique challenges that will impact on the price; there are also many different foams (BLAZELOK TB, FOAM-LOK, BASF WALLTITE, and POLARFOAM are all good medium density foams) but the average job price is about $3.50 + HST per square foot, applied to a depth of 3 inches when dry.

Yazzy 11-25-2010 07:06 PM


Originally Posted by SPS-1 (Post 540494)
That is correct you don't have to go above R40. But then again you don't have to go above R15. R40 is the current Ontario building code requirement for attic insulation on a new home. But you have to understand that the building code does not define the "best" practice. It defines the minimum acceptable practice. In other words, anything less than R40 is so crappy that its illegal.

I have R70 in my attic, and I'm in the banana belt in Windsor.

I agree, but realize also that there is a "law of diminishing return" at work here. Doubling your 'R' rating will not halve your heating/cooling costs and you will reach a point where the cost to improve your insulation value will take to long to recoup and become prohibitive. Your energy auditor can help you figure out what is best for you and your budget. Rising energy costs in the future will work in your favour and reduce the time for your investment to pay for itself.

BTW hope you are using blown in cellulouse and not fiberglass. By being denser, cellulouse will not allow the formation of micro-convection air currents within itself (the way fiberglass does) which decreases the insulating efficientcy.:yes:

Stillwerkin 11-26-2010 01:12 PM

He's right about the sill plate.
"Insulating Basements
A frequent area to leak cold air is where the house meets the foundation. Foundation/basement leaks account for 20% of heat loss in an uninsulated or poorly insulated home.
The important area to insulate isn't the basement walls, but the area where the house meets the foundation.
This is also the place a lot of moisture gets into the house."

I had open-cell sprayed in my basement, and it does stop all the drafts.
It needs to be sprayed with a certain fire-resistant paint where exposed though.

Chemist1961 11-28-2010 08:16 AM

Basement headers and rim joist
I live in KW, ON. Be sure you know your facts, provincial and federal grants are all based on % of improvement when re inspected and % of area improved, in some cases you must do 100% of the area for the grants.
My heating contractor told me up to 15% of all heat is lost through the rim joist and sill plate which sits on the concrete slab. Sealing and insulating mine made a huge difference but do the attic as well. I did these first as my budget was tight. Then I did the furnace as well.
Check your audit, you have 18 months from the original audit date until March 31, 2011 for a re-inspection to claim any credits.
My budget was tight, so I am working in stages, doing everything myself but I have received $3750 back in grants so far which I am now rolling back into the basement completion. I have also saved over $600 a year in gas with the new furnace, which will be 2 years old this Feb.
The original audit was similar to yours and my energy auditor advised to do things in this order, furnace, basement, attic. I skipped the basement walls and then came back to them.
So I added minimum R30 in the attic for max credit, to achieve R45 +. I blew in 16 inches of bagged insulation increased + R30 myself for $290 in 5 hours, then sealed and re-insulated the rim joist in about 3 hours myself for about $180 in material, using spray foam bead in corners and sill plate and Roxul in joist cavities 1100 ft of basement , approx 140 running ft of rim joist.
Rim joist I sealed and added R22 to achieve the *minimum increase* required for maximum rebates, it is now airtight, less drafty, sealed the baseboards as well and reduced my "ACH", air change rate by approx 50% + house is far less drafty now...
So far on first re-inspection with my new furnace installed I have achieved a 57% increase in overall energy efficiency. Upstairs bedrooms are much better winter and summer. But the warmth and air flow through out the house is changing as I tweak things

Stage 2.
I am now sealing and insulating the basement walls to R23.5 below the rim joist with rigid foam and Roxul for the second stage and a repeat evaluation. I will be adding an HRV, and have installed a Power Pipe as well. When done next spring I expect another $3600 in rebates. Given my insulating technique and self labour and some awesome luck finding closeouts for materials, etc,.the basement will be a break even process at best but the comfort and future fuel savings will be the payback.
As you can see there is a lot of grant money at stake plus bonus money (I have maxed the bonus money for exceeding requirements in all categories so far) if you do this work right, but the grants run out this spring and it is too late to register for a re-evaluation extension, so get on this fast. You may also get a furnace manufacturer's rebate right now, but shop carefully for a good installer...
My actual gas consumption with the HE furnace has dropped over 30%, and that will improve further with the basement completion.
Due to poor technique and sealing it looks like your guy acknowledged your basement insulation as mediocre at R1. He gave you a gift here. If he had said it was R11-R13 you would have to increase that whole area to R23.5 Tear it down and do it right ASAP if your budget allows.
Also note your basement is allocated in sections. Complete 100% of the walls or 100% of the rim joist. No grant money if you do say 50- 80% of either.
Pm me if I can help.

Chemist1961 11-28-2010 08:54 AM

More notes
OOPS I stand corrected by my lovely Boss/Wife. "We" did the work in the attic. What a trooper she was. She helped unload and fed all the 30 plus bags into the blower outside, on a beautiful crisp fall day while I just lay there in the attic on my stomach for 5 hours on a foam sled across the joists and fibreglass, arms outstretched with that hose and then raked it level...Prior to which she also hit the switch for the blower with the hose resting in the attic hatch, while I was in the basement looking for my dust mask...and once again when I was almost finished vacuuming the upstairs hall, but then again she only charged me a cold beer when we were done... So thats 50 /50 in my book and a job well done! She's a keeper. She keeps me working...

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