Where is spray foam insulation typically used?  How does it work?

Spray foam Insulation is a relatively new insulating product technology, developing over the past 20 years or so.  The driving force behind the spray foam concept is that to properly insulate a space, you need to provide not only insulation value (r-value) but also a true and proper seal against the worst culprits in heat loss: air and vapour.  Spray foam very effectively provides all 3 elements.

Spray foam has many applications.  Typical locations include walls, crawlspaces, attics, cathedral ceilings, hot tubs, above-ground pool enclosures, under a heated or unheated concrete slab floor...the list goes on.  The only limiting factor is that spray foam is essentially plastic and will melt/burn so it needs to be protected from heat.  See below for a further discussion of this.

What is the R-Value of spray foam insulation?  If I put a plastic vapour barrier won’t the pink fibreglass insulation do the same thing if I put it in thick enough?

R-Value is a somewhat limited measurement of insulation value.  It basically measures a product's ability to retain heat.  It does not, however, take into account air or vapour movement.  Properly applied 2lb spray foam insulation performs at about R7 per inch, so theoretically speaking, a little over 2 inches of pink insulation with a plastic barrier should do the exact same thing, right?  Not really.  Heat loss occurs through air and vapour leakage and transfer.  Imagine standing outside on a cold, windy day wearing a wool sweater – wool is a great insulator but you will be very cold because there is no air barrier.  Imagine that same day, with that same sweater, only it's wet (or even just damp) – you will be even colder!  A plastic vapour barrier would be little more than pulling a green garbage bag on under the sweater.  It would help, but not much.  The analogy is indicative of how leakage occurs in your home and the result – you are cold!  Spray foam insulation not only provides insulating value but also provides an incredibly efficient and effective seal.  Nothing goes through it.  For more on this subject, read this excellent article: R-Value Fairy Tale

It is very important to note that building codes have typically not caught up with technological advances such as spray foam insulation.  For building code applications, an R-Value of 6 per inch is the standard.  Keep this in mind for your renovation project.  For required R-Values in the City of Greater Sudbury, view the following chart (courtesy of the City of Greater Sudbury Building Services Department)

I hear that spray foam insulation is a lot more expensive than other types, how do I justify the price difference?

While the price per unit of R-Value for spray foam insulation is certainly more than other types of insulating products, it is considerably more efficient.  In the end, spray foam's ability to seal a structure against air and vapour movement will lead to incremental savings in heating and cooling costs.  Across a wide sample of spray foam clients, the payback on heating bills is generally less than 5 years.  The following chart illustrates standard values for the most common insulation types:

I’ve received several quotes for spray foam insulation and they vary quite a bit.  Are there different types?

Yes.  There are different densities available.  There are even “do-it-yourself” kits.   Continental Insulation recommends 2 lb closed-cell foam.  It is more expensive at the time of construction but the payback far outweighs the additional investment.

I've done a lot of research and really want to insulate with spray foam but it seems expensive.  Can I get the same results if I buy the kit and do it myself?

Professional Sprayers are trained and certified.  They know how to safely and properly install the product.  They will be able to offer a warranty.  The kits are also very expensive.  The price per board foot for just the material isn't that much different than the cost to have someone do it for you.  The larger the area, the less sense it makes to do it yourself.

Following is a testimonial from a fellow who did a foam installation himself.  The property was a cottage on an island and the cost to hire a barge to transport our large foam rig was prohibitive so he tackled it himself with some assistance and direction from us.  He sent the following as a post-mortem on the process of insulating a small area under his cottage.  With his permission and anonymity we have it here:

There is a reason (or at least a half-dozen) why professionals should be used to do this kind of work.

1) hit the back of my head on a rock...nice lump

2) crawling in confined spaces & 50 years old...a good idea ?

3) even an XXL suit doesn't cover your wrists (I looked like a poodle with tiny foam balls on my fur)

4) as for XXL, I blew out the crotch as soon as I bent over to crawl under the cabin

5) hey, it's hot if you lay UNDER the section you just finished (like a tanning bed)

6) how in GOD'S name do you pull back the suit hood, FIND the little tear off tab, actually pull off only ONE sheet of plastic from the mask without pulling them ALL off, get the hood back on and go back to spraying in less than 30 seconds (the time it takes for the foam in the nozzle to set up and require changing)

 All done, and all good. That stuff, without question, blows the blue Styrofoam SM away !!!

I am interested in having spray foam insulation installed in my cold room.  I’ve been told that if I put a special paint on it that it doesn’t need any other covering to meet building code.  Is that true?

No.  In order to meet building code, spray foam insulation must be covered with a thermal barrier.  There is no paint or coating currently suitable for that requirement.  A thermal barrier is a material which slows the transfer of heat.  The test for any thermal barrier is to put a heat source on one side and measure the temperature rise on the other side.  Any material like paint will transfer the heat almost immediately. 

Using any type of paint will not meet Code and therefore, in most cases, means that you do not have insurance coverage.

While spray foam is arguably the best insulating product available, in certain applications it presents some challenges.  Cold rooms, corrugated metal buildings and other non-concealed spaces where thermal barrier covering is either undesirable or impractical are typically not able to be sprayed.

Typical thermal barriers include drywall and masonry (stone, brick).  Spray applied cementitious fire proofing material is also a tested barrier and is very effective in certain situations when there is no risk of impact or where the entire assembly will be covered with metal sheeting.

Each situation can be unique and a solution should be discussed with a certified installer. 

Meeting building code is very important.  If your property had a fire and the insurance adjuster discovered a code violation, your claim could easily be denied.   Make sure of all the facts before proceeding.  

Be wary of any contractor that tells you a paint will satisfy the thermal barrier requirement.  It will NOT.

For more information follow this link:  thermal barrier

I live in a 50-year old house and suspect that the walls have very little insulation, can I make a couple of small holes and fill the walls with spray foam insulation?

No.  Spray foam insulation cannot fill cavities.  The product is applied with heat and high pressure from a spray nozzle.  When the two liquid parts make contact with the surface, they form and harden almost instantly (about one second).  This creates two possible problems – first, you will have voids in the wall as the foam will not reach all corners; second, as the foam expands in the cavity it is very likely to create a pressure point at the injection point.  It would be very likely that the drywall or plaster could be pushed off the stud by the expanding foam.  Even lighter density foam can cause this.  Be careful when filling cavities!

I understand that attic spaces require proper ventilation, but I have a cathedral ceiling that I am redoing.  Does spray foam insulation require venting in that situation?  How would you do that?

There has been a great deal of research and some controversy over this issue.  Building code in many areas strictly calls for ventilation in roof attic spaces but those codes have often not caught up to the state of advancement in product performance characteristics.  There are a number of research papers available providing deeper insight.  Each situation is unique but, in general, installing compact foam venting channels behind the spray foam insulation in a cathedral ceiling will ensure trouble free performance.  Some additional research material on the subject of venting:

Issues Related to Venting of Attics and Cathedral Ceilings

Cufca Technical Bulletin on Cathedral Ceiling Venting

Reesor Report on Ventilation for Roof Spaces

Is there a lot of odour when the spray foam insulation is being applied?  Does my family need to vacate the house for a certain period of time?  I have young children, is there any toxicity we should be concerned with?

The foam-forming reaction occurs in seconds and the curing is 100% complete well within 24 hours.  Any off-gas is very minimal and completely gone within hours.  The odour from BASF Walltite ECO spray foam insulation is about the same as a latex paint but lingers for a much shorter duration.  

The failsafe precaution for any foam installation is 24 hours.  For any person that has asthma, allergies or other respiratory difficulty, as well as young children and elderly persons, vacating for this duration should be mandatory.  Once the foam has cured (max. 24 hrs), there will be no further off-gas for the life of the product.

The sprayer will secure the spray site to a safe perimeter and ensure the work is done in the safest possible way.  In any interior installation, exhaust fans will be set up to vent the fumes.

We would be pleased to answer any questions and/or provide detailed technical information about the product, installation procedure and health and safety requirements.

I get a lot of ice build-up on my roof and have been told that I don’t have enough insulation in my attic.  How can I add spray foam insulation to help that?

One of the biggest causes of ice build-up on a house's eaves is leakage of warm air into the attic space.  Spray foam insulation's key feature is its ability to effectively seal against this leakage.  Theoretically, it would be the ideal product for the attic.  In practice, there are some logistical and cost issues.  First, as discussed above, spray foam insulation must be applied directly to a hard surface, it cannot be 'blown in' atop another insulating product.  As such, in any attic space with existing insulation, that material must be completely removed prior to installing spray foam.  The cost of this removal can be prohibitive, though in many retrofit situations, the existing insulation contains asbestos and must be removed regardless.  Second, spray foam insulation is expensive.  At R-6 per inch, to effectively insulate an attic to R-40, you would need almost 7 inches.  For most, the cost would be prohibitive.  However, a very successful and effective compromise is to put a base layer of one and half to two inches of spray foam insulation and then blowing or batting up to the desired R-Value.  Doing this achieves a rated air and vapour barrier combined with an economical R-Value attainment.

How much insulation do I need in my ….?

Minimum insulation thickness is decided by building code.  Every region has its own code and interpretation. For the City of Greater Sudbury, refer to this chart.

I am trying to get a rough idea of how much spray foam insulation will cost, how can I estimate that?

Record the dimensions of the area to be insulated.  Indicate where the area(s) are (attic, basement, crawlspace etc).  Also, please indicate the location of the building to be insulated if it outside the City of Greater Sudbury.  Provide this information in our handy inquiry form or give us a call at (705) 692-3311.  You will receive a reply within the same business day.

How long does it take to install?

Obviously it would depend on the size of the job.  Generally, for most residential jobs we can be finished in one day.  New construction where we are doing an entire house could take up to 3 days or longer.

Do I still need a vapour barrier if spray foam insulation is being installed?

There is some varied opinion on this point.  Spray foam insulation at one and a half inches thick is a recognized vapour barrier.  If it is installed between metal studs, there is no need for a vapour barrier.  If the studs are wood, some argue that a vapour barrier is needed for the studs because wood is porous.  Others would say that the penetration through a 2x6 stud is so minimal that it does not warrant the additional cost of a vapour barrier.  In commercial applications, at any material transition point, a sealing membrane is required.

Where can I get more information?

The Canadian Urethane Foam Contractors Association website is a great source of information cufca.ca

For specific questions on your home or to book an appointment, contact us using our inquiry form.