[Converting a 1920’s house from a leaky vented attic to a foam roof semi-conditioned attic.]

What is the big problem?


How we solve the problems with a spray foamed roof?

Creating an encapsulated attic addresses the 4 major heat loads on your home that equate to about 50% of the total heat load.

  1. air seals all attic penetrations
  2. permanent proper insulation levels
  3. duct leakage stays in building envelope
  4. ducts deliver 55* air during cooling season

Stellrr recommends installing R-25 nominal fill of open cell spray foam in attics. This is IECC and COA performance code compliant. Gable walls are installed at R-13.


Before & After – Moving the insulation from the floor to the roof.

[BEFORE – Attic floor insulated]
[AFTER – Attic roof sealed & insulated, attic floor clean]

What R-Value do you need on your attic roof deck?

Do you need R-38 foam which is the minimum code requirement for blown insulation on the attic floor? You can read about the difference between Prescriptive Code requirements and Performance Code. With foam we are meeting or exceeding the Performance code requirements, so we are doing well at R-25 open cell spray foam on the roof deck.

On Shawn’s personal home, it was built in 2011 by Meritage Homes. Back then, the code requirements were R-20 for the city of Austin. R-20 is just not enough. Shawn was able to take his thermal camera and get significant variances in temperature with the R-20 foam. So he had one of his sprayers add R-5 of Icynene open cell to the existing open cell spray foam insulation. Now the thermal camera registers the entire attic roof as the same temperature.


How do we do it?

Check out this video of a Barnominium where we installed closed cell spray foam. You’ll also get s sneak peak at the spray foam rig. 


What is the process? Where do we install insulation?

First the existing insulation is removed. The attic is updated to allow for effective and safe encapsulation. Ensuring bath exhaust fans are ducted outside. Manage any combustion unit make-up air ventilation rooms, build a mesh wall to foam and seal the porches and garage off from the main attic.  Next is sterilizing.

Then we install spray foam to the underside of the roof decking. The roof decking is the wood that your shingles are nailed to from the top side. We cover any ridge vents, roof vents, block the soffits, cover the gable end vents, etc. Then we spray the roof, the gable walls, and everything down to the top plate. This seals your attic  



How messy is the removal and installation process?

Anytime insulation is sprayed or blown in there will be a cloud of dust or vapor. We use fans to suck out the stuff in the attic air. However, the inside of the house is separated from the attic with your drywall ceiling. So really nothing should get inside the house other than a slight odor. With that said, we do recommend opening the windows and turning the ceiling fans on to help air out the place.

Plus, when we are done we always recommend having a house cleaner come out and deep clean everything. You just had construction done on your home. No matter how much preparation we do to protect everything, and how good we clean up, there will be something left behind. So it is better just to be safe and get a cleaner you trust to make your upgraded home shine.


What is included in the spray foam line item? Garage & Porch?

We install foam on the underside of the roof deck and gable walls over the conditioned space. We block off the porch and garage. If we are spraying the garage, it will be a seperate line item.

Our quotes are based on the Central Appraisal District footprint of the house, plus roof pitch.

The garage and porches are always a seperate line item on the CAD, and thus if we are insulating them, it is a separate line item there too.

If the house attic is shared with the garage attic, code requires that the house attic be separated from the garage attic even if we are also foaming the garage. Why? They want to prevent any potential vapor from the garage going over into the house. So we build a mesh wall, install a zip door, and then foam the wall to seperate it. 


What are the unique precautions Stellrr takes to ensure an excellent install result?

  • Block soffit so it doesn’t spray out the soffit onto your siding ruining it.
  • Protect the attic access hatch so we don’t mist overspray onto the inside of your house.
  • Put down protection for your flooring so we don’t leave a trace.
  • Block the gable vents, roof vents, ridge vents so foam does not spray out onto your roof and ruin it.
  • Build walls to block the house attic off from the porch attic.
  • Build walls to block the garage attic off from the house.
  • Install sealed access doors to blocked off areas if access is needed.
  • Seal down to the top plate on the house perimeter so there is no air gap, and it fully stops the air leakage.

What is excluded?

Spray foam is a plastic based material and therefore has a lower smoke, and ignition point than do other materials like Rockwool (which is fireproof). 

According to International Residential Code (IRC), spray foam is to be coated with an ignition or thermal barrier under certain conditions. 

The spray polyurethane foam we install is Class 1 Fire rated which is the safest class. Commercial buildings require Class 1 Fire rating on materials. 


What is an ignition or thermal barrier? 

A thermal barrier is a 15-minute barrier that allows you 15 minutes to get out before the barrier is compromised.

A ignition barrier is a thinner layer of material that helps prevent the foam from igniting, but is not as strong as a thermal barrier. 

A thermal barrier is having spray foam in walls, then the walls get covered with 1/2” of drywall. Or a cathedral ceiling with with foam on the underside of the roof deck with 1/2” drywall attached to the rafter tails.

A thermal barrier IS NOT, having a foamed roof deck on a 2/12 roof pitch with drywall attached to the underside of the ceiling joists. 

In general, what does IRC code want and where?

If the attic is over 30-inches tall and more than 30-square feet, but is only entered for mechanical service, then IRC wants an Ignition Barrier to be installed. 

If the attic has more than a sheet of plywood decking where stuff can be stored, or has a regular walk in door where people could hang out, then IRC wants a Thermal Barrier to be installed. 

What is qualifies as a thermal or ignition barrier?

In 99% of cases, the barrier installed by insulation contractors is called an intumescent coating. This is a “paint” that is sprayed onto the foam AFTER foam is installed.  

What is special about the intumescent coating is that when it comes into contact with a flame, it EXPANDS UP TO 2,000% to thicken and create a barrier between it and the spray polyurethane foam. 

Foam is an uneven surface, so it requires that the coating be sprayed on instead of brushed or rolled on. The viscosity of the coating is such that to install the paint requires about an $8,000 industrial paint sprayer. We use our sprayer almost daily.

Why didn’t Stellrr’s competitors notify me about this building code?

While this is the code requirement, there is a lot of malpractice in the industry. In fact, when my home was built in 2011 by Meritage Homes, I was not in the insulation business yet. My whole house was foamed. My attic required an ignition barrier. I thought my attic had one installed. 

It was not until a few years ago when I had one of my sprayers upgrading my house from R20 to R25 that we realized the original foam company cheated and never got caught. 

The foam company painted my attic foam with interior wall paint. I assumed it was an intumescent coating until my sprayer (who had been installing for 15 years) reminded me that the coating does not come in the color my attic was painted. 

When being built, I had my house inspected by a third party inspector, a city of Austin inspector, and the superintendent. Not one of them caught this scam. 

I suspect there are millions of foamed attics that failed to comply with this code.

Anyway, after upgrading my attic, I also installed not just the Ignition Barrier required, but I upgraded to the Thermal Barrier level just to be safe. 

Do I have to install an intumescent coating? What happens if I decline it?

Stellrr’s job is to inform you of what is supposed to be done. If you knowingly decline the protection, that is your choice. 

I have never heard of a Fire Marshall going an inspecting an individuals attic when they have a drywall ceiling. 

(In Round Rock we foamed Fire Station #1, and got to install a Thermal Barrier to the entire roof, including in the Fire Marshall’s office. That was fun!)

However, here is what I have seen happen. If you house gets struck by lightning, or has an electrical fire… and you don’t have a code compliant intumescent coating… how much risk can you tolerate? Will your insurance company approve or deny your claim because they have your foam tested and find out that you don’t have an intumescent coating? What happens when you go to sell the house, will you have to pay for it then?

What are the alternatives to an intumescent coating?

Foam manufacturers know that this code is an added cost. So they have attempted other types of lab tests. One of which is called a Corner Burn Test. Where they start a fire in a corner, and use Oxygen Deprivation to extinguish or manage the fire. While this fire testing can be effective, it is not code approved. 

With that said, I have been documenting sealed, spray foamed attic fire occurrences across North America. I talk to other foam companies monthly about these cases, whether or not there was an intumescent coating, and look at the photos.  What I have found is that properly installed foam, does seem to suffocate the fire. The homes are much more intact than homes with a leaky fiberglass building envelope that feeds the fire, allowing fire to spread. I don’t see melted foam, if anything it has smoke damage or a little char. 

There are also homes like one sprayed by a competitor in Liberty Hill that was 1 year old and had a dryer vent fire. We did the demolition on the house with my sister company Dumposaurus. The entire house had to be demolished. 

What about Appendix X foam that has some ignition barrier in it? Is that good enough?

We used to install Appendix X (OCX) foam, but will never again. OCX is a weak attempt at an ignition barrier and very fickle. First, it still does not meet code, regardless of what you may be told. Second, the B side (resin) is sugar based. Aren’t we supposed to try to repel insects and rodents instead of attract them!? Third, it is prone to a number of installation errors that installers can cover up but leave you with a damaged home. The OCX has to be constantly agitated in the 55 gallon drum. and the installer cannot take any breaks or the resin separates in the hose, and is bad. If the foam gun is idle for 10+ minutes, everything has to be broken down, flushed out, and re-started. Do you think the installers like all this extra work or do they take shortcuts?

So what happens is when these installers start spraying bad foam, they just spray it and try to cover it up with the good stuff later. If you ever pull back a handful of foam in your attic and see Swiss cheese or honeycomb, you have bad OCX hidden in your attic. This is common. Very hard to manage, and is just one more reason why we will not install this formula. 

What if I wait to have the ignition barrier installed later?

Some people go this route. Installing it is has to happen after the foam is installed. So we can wait a few days, weeks, or longer to install it. But, the question is, how much risk are you comfortable taking on. Your decision. 


How are gas / propane utilities handled?

Does your attic has gas or propane combustion utilities like an HVAC or Water Heater (WH) that use your attic for make-up air to feed the combustion? If yes, then we will have a seperate line item for a Combustion Ventilation Closet for how we handle these items to create a sealed envelope while still bringing in the 1-for-1 make-up air exchange.  

If your HVAC or WH flue pipe through the roof is PVC plastic, that is because it is 95% efficient or greater. It means that the unit brings in combustion air through that PVC pipe, and has an inner layer where it exhausts out fumes. 

If you have a metal pipe going out your roof from the WH or HVAC, then you probably have an 80% efficient unit, meaning it requires attic make-up air. So we will have a seperate line item to build out a Combustion Air Closet. The closet will have a zip door on it so that the tech can come in, service the equipment and do any needed work. Then zip it back up upon leaving. 


What happens when I need to replace my 80% HVAC or WH? 

Great! Now you can upgrade to a more efficient and smaller unit. That means that the Combustion Air Closet is no longer needed. It can be demolished in less than 2 minutes with a baseball batt or 10 minutes with a hand saw. Very easy. Now your new unit can go in with zero obstructions. 


What if I need work done? 

Once your attic is converted from blown insulation on the attic floor, to foam on the attic ceiling, it is a workers dream come true. 

The problem with blown insulation on the attic floor is it is always in the way of any work needing to be done. Technicians will damage the blown insulation walking through your attic to run wires, fix plumbing, check the HVAC, or Water Heater, etc. The same thing with pests, they scurry through and damage the insulation. 

However, a foamed roof is up and out of the way. There is clean and clear access for whatever work a technician needs to do. It is also a cool safe environment for them to work. If you ever have pests enter the attic, you will hear them loud and clear walking on your Sheetrock. Then with a clean, clear attic, you can find them and get rid of them asap. 

Growing up, the house I live in had a spray foamed roof. I had access to storage under that was exposed to the foam roof. Never once did I see any of the foam damaged in my childhood home. My parents sold their home a few years ago, 20 years after building it. When we were prepping it for sale, I inspected all of the foam insulation, still no damage. Perfect condition. But can you imagine if it was blown insulation? It would be a disaster. 


What about roof leaks, repairs, or replacing the roof?

My childhood home, mentioned in the paragraphs above, had the roof replaced just before my parents sold it. The house was 20 years old and had been foamed. Of the entire house, there was part of a sheet of decking that needed replacing. The decking was in a valley and had some rot. It came up without damaging the foam, and was replaced. Easy. 

I’ve asked several of my roofing friends about their real world experience here. They say that open cell foamed roof DO allow them to find leaks. Open cell is porous and allows moisture to come through close to the leak location. 

They say that only 3-5% of roofs need any decking replaced, and at that, it is usually only a sheet of decking regardless if it is a foamed or blown in roof. 

If you have to have your roof replaced, it will probably be done with insurance money. So if any foam has to be repaired or replaced, the insurance will cover that as well. But guess how many calls or jobs we have done to repair foam after a roof replacement? We did one job years ago. And it was not because the foam needed repairing. The foam was attached directly to the metal roof. The metal roof was damaged when their carport was blown onto the roof and dented it badly. The roof was able to be removed without damaging the closed cell foam. The building owner wanted to replace the foam because he didn’t like the job my competitor did, and he wanted it to look pretty. So he hired us to re-do the foam 100% since it was a metal building with exposed foam. 


Why do shingle manufacturers make a big deal about spray foam? 

Check out my video on Fiberglass and Owens Corning. OC sells shingles. OC sells pink fiberglass. They do not want you to buy other products. They want the builder to buy their entire product line. And they trash foam. 

The truth about foam is that it does raise the shingle temperature about 5 degrees. But that is it. If shingles cannot handle 5 degrees more heat than we get in Austin, then they better not sell shingles in other parts of the country where it is 5 degrees warmer than Austin.  


Doesn’t my house need to breath?

Seal it Tight. Ventilate it Right. A leaky house is not healthy for you or the house. A sealed house without mechanical ventilation can be troublesome as well. So the answer is to seal it tight so that you can control everything. Then set up the mechanical ventilation so that only “breathes” as much as is necessary.

So what happens if you spray foam my attic, converting it from a vented to a encapsulated attic? Will it be too tight?

No. You will still have leaky walls & windows and bottom plates, and doors opening. This is sufficient. However, you can upgrade your mechanical ventilation, so that you introduce a certain amount of air into your house at set intervals daily. If we are building a combustion closet for you, we are still bringing in fresh (make up) air into that closet, so fresh air will be introduced. But you can also have what is called an Energy Recovery Ventilator (ERV). ERVs are a luxury, and rarely installed even in new custom build homes.

Your tight house will now allow you to manage the humidity inside the house. One way of managing the humidity is through our SaniDry dehumidifier system.


Humidity Management in Efficient Homes

Let’s talk more about moisture in the air. Austin is a very humid environment, often 80-90% humidity. This creates a great environment for all sorts of things to grow. If we are constantly bringing in humid air from outside, then we are creating a not so healthy environment inside. We need to seal up the house air leaks not only for energy savings & comfort. But we need to seal up the house for our health. Then we can manage the humidity more effectively. And we can stop mold growth, wood rot, and protect the house structurally. 

Do you need a dehumidifier? If your house is sealed up properly, your HVAC unit will pull the humidity out of the air effectively in the summer, while avoiding bringing in excess outside humidity. But, in the cool part of the year, if your house is efficient, you won’t be running your HVAC enough to pull the humidity out of the air.

In Austin, it is a good practice to have a self-draining dehumidifier like SaniDry installed either in your crawlspace or attic. 

We recommend that every house have a SaniDry dehumidifier installed. SaniDry is always a separate line item. Learn more about having a SaniDry installed in your attic.