Home & Garden

Ask me anything about spray foam insulation

  • Last Updated:
  • Jul 3rd, 2018 9:18 am
Deal Fanatic
User avatar
Sep 1, 2005
5295 posts
1078 upvotes
Markham
Since you get a vapour barrier with 1 5/8" of high quality foam....do you still have to add plastic? There's been discussions that inspectors don't know that foam can be a vapour barrier and thus ask for plastic.

What about the future...if you don't use plastic and you need to cut/replace the drywall, will the foam stick to the drywall thus making removal and replacemenet of drywall difficult? If you've cut drywall and foam, how do you "fix" the cut foam?
We're all bozos on the bus until we find a way to express ourselves...

Failure is always an option...just not the preferred one!
Deal Addict
User avatar
Dec 10, 2008
3781 posts
411 upvotes
Toronto
Little Tim wrote:
Feb 6th, 2014 9:56 am
Now, let me ask you this: As a layman, are you able to gauge the quality of a batt insulation job? Do you realize that the mold and rot problems caused by a bad batt insulation job could be enormously damaging to your house?
Hyperbole, much?
Banned
User avatar
Jun 22, 2012
4737 posts
674 upvotes
Shhanada
Bullseye wrote:
Feb 6th, 2014 6:32 am
This was the story I was referring to. I've always thought of foam as a good reno to do to your house, and I still do, the problem is that a layman like myself has no way to gauge the quality of the foam or the job being done, not being an expert at it. So I'm a bit put off on doing it for now, I want it to become more mainstream and there are established companies with solid reputations for I take the risk.
What concerned me was the industry was saying these problems are extremely rare, however they refused to stand up as an industry and offer to indemnify/fix these problems.

If these probably were truly rare as they claim, they should have no objection to remediating that one in a million install that goes bad, right?
Banned
User avatar
Jun 22, 2012
4737 posts
674 upvotes
Shhanada
Little Tim wrote:
Feb 6th, 2014 9:56 am
More mainstream??? Spray foam has been used as insulation for decades and has for example been featured by Mike Holmes on almost all his reno shows.
I think Spray Foam has become more popular in recent years, I don't think it was used very much "decades" ago. In fact I know the person who did one of the first residential installs here less than 15 years ago. He had a bear of a time getting it approved as not one person in the permitting and inspection departments knew the slightest thing about it.

Little Tim wrote:
Feb 6th, 2014 9:56 am
Do you realize that the mold and rot problems caused by a bad batt insulation job could be enormously damaging to your house?
I don't think this is an accurate/fair comparison. Removing batt insulation is dead easy. Removing spray foam that's adhered to everything is the opposite of easy. In some cases it's downright impossible, leading to entire joist structures having to be removed.
Deal Addict
User avatar
Dec 10, 2008
3781 posts
411 upvotes
Toronto
SurplusPlus wrote:
Feb 6th, 2014 5:16 pm
I don't think this is an accurate/fair comparison. Removing batt insulation is dead easy. Removing spray foam that's adhered to everything is the opposite of easy. In some cases it's downright impossible, leading to entire joist structures having to be removed.
...and have fun adding any new electrical.
[OP]
Jr. Member
User avatar
Feb 3, 2014
128 posts
53 upvotes
Mississauga
sickcars wrote:
Feb 6th, 2014 10:04 am
Whats your opinion on say spraying a wall with 1inch spray foam to make it airtight & then using regular sound proof batts for the rest? Any issues I would run into?
This method of insulating is good but if you decide to put an additional vapour barrier over the fibre glass then you’re going to be trapping air between the 6mil and the spray foam which is not a good idea. An inch is a good start but why not go and have 1 5/8 to 2inch done to achieve the vapour barrier as well as the air barrier and then fill the rest of the cavity with fibre glass?
gr8dlr wrote:
Feb 6th, 2014 10:38 am
Since you get a vapour barrier with 1 5/8" of high quality foam....do you still have to add plastic? There's been discussions that inspectors don't know that foam can be a vapour barrier and thus ask for plastic.

What about the future...if you don't use plastic and you need to cut/replace the drywall, will the foam stick to the drywall thus making removal and replacemenet of drywall difficult? If you've cut drywall and foam, how do you "fix" the cut foam?
Spray foam does not have a CCMC number for vapour barrier yet, but over 95% of the building officials I come across pass it off no problem provided that whenever you have a double wall stud (2 pieces of framing sandwiched together) that you put a bead of acoustic sealant (rubberized tar) to keep the vapour barrier between the studs. I cannot guarantee that the building official will pass it, though. Spray foam when applied properly onto a concrete wall will outperform what the minimum coat is for vapour barrier by three times (the building code is 60 nano grams of vapour permeance per sq meter per second. 3 inches of foam on a concrete block will give you 22 nano grams of vapour permeance per sq meter per second). So ideally if you’re doing it in a basement, you should pull your frame studs away from the wall at least half an inch for the foam to go in behind and create a monolithic seal all the way across your exterior walls (one giant piece of foam without any thermal breaks). Above grade is different because of traditional stick framing but spray foam combined with acoustical sealant will provide you with the vapour barrier you need provided that the building inspector is knowledgeable about new technologies.

Normally spray foam is installed before drywall and there is a .5inch gap between the two. Unless it is .5lb pound open cell foam, then they will spray your cavities full, but it still doesn’t adhere. The only time it adheres to the drywall is if you use a “drill and fill” product. You can fix the foam by using foam in a can (5% of any spray foam job can be non-certified foam).

--
Peter
Owner, VIPFoam.com
--
Peter
Owner, VIPFoam.com
Newbie
Nov 6, 2011
29 posts
9 upvotes
Hi there,
I have a covered porch that is absolutely freezing as it has no adequate insulation. I've ripped out the inside of the room down to the studs (walls and ceiling), but the flooring is tiles that I intend to keep. I plan to get a company to spray foam the walls and ceiling with 2lb foam. I'm installing a baseboard heater to provide supplemental heat.

My question relates to the underside of the floor.*Under the tiles is a single layer of plywood and then joists. There is 3ft of open air below that. I'm hoping that the foam will provide enough heat and moisture insulation so I don't have to do anything more elaborate. Is this reasonable? When they spray the foam on the underside, should they cover the joists completely or only the space between the joists? My worry is if they only fill the space between, the wooden joists would transfer moisture up under the tiles.

Any comments?
[OP]
Jr. Member
User avatar
Feb 3, 2014
128 posts
53 upvotes
Mississauga
zekicker wrote:
Feb 11th, 2014 5:46 am
Hi there,
I have a covered porch that is absolutely freezing as it has no adequate insulation. I've ripped out the inside of the room down to the studs (walls and ceiling), but the flooring is tiles that I intend to keep. I plan to get a company to spray foam the walls and ceiling with 2lb foam. I'm installing a baseboard heater to provide supplemental heat.

My question relates to the underside of the floor.*Under the tiles is a single layer of plywood and then joists. There is 3ft of open air below that. I'm hoping that the foam will provide enough heat and moisture insulation so I don't have to do anything more elaborate. Is this reasonable? When they spray the foam on the underside, should they cover the joists completely or only the space between the joists? My worry is if they only fill the space between, the wooden joists would transfer moisture up under the tiles.

Any comments?
It’s highly unlikely that the wooden joists will transfer the moisture. Technically, according to the minimum building code, your plywood layer should be acting as your vapour barrier but anyway, with 2lb density foam between the joists the moisture has a long way to travel. We’ve done many installations this way where we’ve sprayed 4.5” R31 in between the floor joists and have had great success without any complaints. Personally, I would do it this way and as for covering the joists with foam or filling the entire cavity: it would get more expensive and would also take more than one day to do the job. Most importantly, you won’t see much benefit from it.

--
Peter
Owner, VIPFoam.com
--
Peter
Owner, VIPFoam.com
Deal Guru
User avatar
Feb 8, 2014
14608 posts
4077 upvotes
For a basement of an older home, its painted brick that has had some minerals building up on it (presumably water minerals slowly migrating through the foundation) and bubbling the paint off, should i just peel the paint off and leave it uninsulated, or is foam insulation worth pursuing (maybe the open cell that will let the water evaporate away)?

Also i have seen a roof foam application that had lots of major air cavities in it (which was only discovered by chance when one of the gaps had a pinhole leading to the inside), most of the roof had to be resprayed. I assume this significantly reduces the foams insulating performance and my concern in getting foam spraying in future is to prevent this, is there any way to check for this after installation or to make sure it doesn't happen in the first place?

Finally what is the fire resistance of the available spray foam options?
[OP]
Jr. Member
User avatar
Feb 3, 2014
128 posts
53 upvotes
Mississauga
Quentin5 wrote:
Feb 15th, 2014 12:52 am
For a basement of an older home, its painted brick that has had some minerals building up on it (presumably water minerals slowly migrating through the foundation) and bubbling the paint off, should i just peel the paint off and leave it uninsulated, or is foam insulation worth pursuing (maybe the open cell that will let the water evaporate away)?

Also i have seen a roof foam application that had lots of major air cavities in it (which was only discovered by chance when one of the gaps had a pinhole leading to the inside), most of the roof had to be resprayed. I assume this significantly reduces the foams insulating performance and my concern in getting foam spraying in future is to prevent this, is there any way to check for this after installation or to make sure it doesn't happen in the first place?

Finally what is the fire resistance of the available spray foam options?
Open cell is a terrible idea below grade like in a basement; it's like insulating with a sponge that will absorb water. The mineral deposits that you see are efflorescence deposits. Personally I would address this issue with a stiff wire brush to knock off the loose paint and have it professionally spray foamed with 2lb density closed cell foam, thus preventing the deposits from coming through. As water enters your basement it's going to create mold and mildew as well. If you have any significant water penetration you may want to look into exterior water proofing. But 2lb closed cell spray foam should take care of your problem and keep it nice and warm.

On rare occasions I have seen air pockets form on half pound foam. On 2lb foam it's extremely rare especially when installed properly. If you have someone spraying 4-5inch passes of 2lb foam then you’re asking for trouble. With foam you can tap and listen for hollow cavities, but if you’re using 2lb with a reputable installer you shouldn’t have to.

I’m not an expert on the half pound because I don’t believe in the product as a thermal insulator, but here is the fire resistance for a few types of 2lb foam: Polar Foam Soya – 200. BASF Eco Walltite – 315. Certa Spray – 275. Foam-Lok – 470 (lower number is better). In most living spaces excluding attics or crawl spaces foam should be covered with an approved thermal barrier such as drywall or AD fire retardant spray. In some cases an intumescent paint/coating can be approved by your insurance company but is not approved by building inspectors.

--
Peter
Owner, VIPFoam.com
--
Peter
Owner, VIPFoam.com
[OP]
Jr. Member
User avatar
Feb 3, 2014
128 posts
53 upvotes
Mississauga
Anonymouse wrote:
Feb 16th, 2014 10:17 pm
Which is cheaper to insulate two 20x12 ft. walls in an uninsulated, drywalled garage -

1. stripping drywall, insulating with fibreglass, installing vapour barrier, and re-drywalling, or
2. injecting closed cell foam into the existing wall cavities?

I am going to let a turnkey contract this summer.
I’m not a fan of the drill and fill method, but usually when it comes to regular spray foam compared to fiberglass, it’s 3 times as expensive up front but 10 times better in the long run. If you plan on staying in the house for 5 years or more, it’s cheaper to have foam than fiberglass on account of the energy savings and the fact that you will never have to re-insulate.

--
Peter
Owner, VIPFoam.com
--
Peter
Owner, VIPFoam.com
Member
User avatar
Mar 25, 2012
421 posts
86 upvotes
Toronto
I'm considering spray foaming my basement walls and rim joist. I had one contractor tell me I will get a lot more spiders with spray foam as opposed to other methods, is there any truth to this? I don't see how one method over another would change the amount of spiders in a house.

Thanks
Deal Addict
Jan 25, 2007
4367 posts
1399 upvotes
Paris
SurplusPlus wrote:
Feb 6th, 2014 5:16 pm
I think Spray Foam has become more popular in recent years, I don't think it was used very much "decades" ago.
I remember seeing my Uncle's basement who lived on a 100+ year old farm being done when I was 8 years old and getting in HUGE trouble for picking it off the walls months later. I was 8 in 1982, so its at least been around that long.

Oh, and he still lives in that house and its still going strong (also, its exposed and he has a wood/oil hybrid furnace down there). Fire hazard much? His kids have had it done to their houses years later.
Deal Guru
User avatar
Mar 14, 2005
11663 posts
1664 upvotes
City of Vancouver
Has the OP ever spray-foamed over a greasy attic or smokey (smoke from a fire) attic?

Top