Insulating Your Attic Space!

The best home improvement money you will ever spend…

This is a slightly confusing topic with a lot of options. Your personal decisions whatever they may be will result in the following benefits:

Give you the ability to claim a Tax Credit
Lower your Heating Bill
Lower your Air-Conditioning Bill
Lower the Ambient Outdoor Noise inside your unit, and
Raise the Selling Price of your unit.

Things to think about…

This job is not an easy job, especially in our Condominium Association. Our roof slopes are quite flat which makes the labor miserable and physically demanding, also our roofs are complex and often have partial inaccessibility issues which increases the labor hours needed to do the job right, and depending on the logistics of the equipment it can require that the heavy machine and its materials be brought up to the second floor. At Harrogate Square, we have limited access to our attic spaces. For some unit owners, a new hole in the ceiling will need to be cut just to look inside the attic (more details on this later). In other words, low-priced estimates should not be expected, and if you get one too low, they might be inexperienced. To be responsible to yourself, you should try to get 3 separate quotes from unrelated contractors; that’s harder than it sounds.

One of the first things to worry about is what type of insulation to use. There are three basic choices, fluffy fiberglass (like cotton candy), cellulose (like dirty dry baby food), or expanding foam (goes on wet and swells up to become as hard as dry glue). Each has its own pros & cons.

Before going over those details we need to talk about how our attic spaces are shared and the implications of that.

Illustration depicting a 3-D view inside an attic space

This sketch above is a simplification of a shared Harrogate Square attic space to explain heat management and insulation choices. The options of which insulation to select depend partly on your objectives for insulating. In an ideal world, you and the neighbor who shares an attic space will team up and get both units insulated at the same time with the same choice of insulation.

Here are a few things that are noteworthy if that does not happen. Bear in mind that Ice-Dams are the real problem some of us face, and Heat Loss from our ceiling is a big part of the cause.

Suppose you own 88 and your neighbor owns 86.

Scenario 1: You do the typical fiberglass insulation on the ceiling and they do nothing. The result will be you get all 5 benefits listed above, but you will still have half the Ice-Dam problem you had in the past. This happens because unit 86 still has full heat loss into the attic space and their heat loss has no way to stop from warming your shingles because the firewall separating you and Unit 86 only comes up to the 2nd-floor ceiling. Your warm shingles melt the snow and then the water rolls down towards the gutter, and at the low end of your roof, there isn’t heat loss so it freezes quickly at or near the gutter.
This method should also lead to a significant improvement in air conditioning for the summer.

Scenario 2: You decide to do the liquid spray on expanding foam-type insulation up between the rafters (the boards supporting shingles), and your neighbor does nothing. The result would be, you get benefits 1, 4 & 5 in full, but only 2 & 3 partially. Because heat loss happens at the ceiling, you will still lose heat all winter as usual, but now it won’t be able to heat your shingles. You will certainly be completely Ice-Dam free, but since none of the heat loss goes out of your shingles, it all goes out of your neighbors. They will likely get double the Ice-Dam problems. In the summer, you will have some money savings on air-conditioning. The heat from the sun can’t get through your roof, but it does go through your neighbor’s shingles, and that heat in the attic radiates through both your ceilings indiscriminately.

Scenario 3: You combine scenarios 1 & 2 in some way. You insulate both the ceiling and the rafters; either you use only spray-on, only blown-in, rolled materials, or some hybrid of the two. You will have the rafter space under the shingles thermally protected, and the joist space above the ceiling thermally protected. In this case, you spent double on materials, and almost double on labor, but you will be bulletproof from the heat loss of your neighbor. The snow won’t melt on your shingles and you get all 5 benefits listed above. In the summer, you will have maximized your money savings on air-conditioning. First, the amount of expected heat accumulation from the Sun in the attic space is halved from the rafter insulation, then what is in the attic can’t get past your ceiling insulation and has to prefer your neighbor’s ceiling.

Typical types of insulation…

One detail to bear in mind is there are reasonable recommendations of what types you can add on top of other existing insulation. Any owner between the original build and your ownership could have upgraded the insulation in some way.

The only insulation that was installed at the time of the original construction of Harrogate Square in the 1970s was a second-rate type of yellow fiberglass rolled insulation. They used wall-type insulation in our ceilings. Wall insulation is R-13 rated at 3.5-inches thick and currently, ceilings in our Zone 5 are recommended to have R-38 which is 12.5-inches thick (if it’s a rolled type of fiberglass). Furthermore, that itchy yellow type degrades much faster than the Owens Corning pink type, so your yellow ceiling insulation is only about 2-inches thick now. Later in this post, I’ll detail why thickness matters. The contractors you call to get estimates from will tell you what your current status is and what your options are.

Cellulose can claim it’s the most Eco-Friendly because it comes from recycled materials, takes little energy to produce and the base material is organic carbons, so you are sequestering carbon by flooding your attic with this.

When Cellulose was first on the market, it was basically pulped, recycled newspapers treated with formaldehyde to make it fireproof. The R-Value per inch is competitive with rolled fiberglass insulation, but it’s superior per inch of thickness to the AttiCat blown-in fiberglass insulation. This is a significant factor because the 2017-2019 roofing upgrade added ventilation through the soffits.

Your contractor won’t fill to a thickness taller than the height of those baffles that keep the attic ventilated. If you’re the “extra” type, this is your choice. You can get over an R-60 thickness up there.

If you are an avid Do-It-Yourself’er, this method is within your reach, but you can almost forget about the tax credit because you don’t have a paper trail for the installation. You’ll also need a second person to help.

If you ever have to go back up in the attic after this stuff is deployed, you must wear a mask because this stuff fills the air with dust when disturbed by your feet.

Fiberglass is probably the most common of all insulation options. There’s a difference between the AttiCat depicted here and the rolled type. Rolled has better R-Values per inch installed, but also requires a sufficiently large access hole to get the materials up there. Rolled also can be pulled back to do modifications and then put back in place, where the fluff goes everywhere and begins to compact a bit as it’s pushed around and handled.

Some glass dust can be expected as this is hosed into the area, so masks are required, but after it’s done you won’t encounter dust like Cellulose gives off when disturbed.

The machinery for this type is a bit more complex than the Cellulose spreader, so rookies will run into trouble keeping the job going smoothly.

This method is also a viable choice for the avid Do-It-Yourself’er. Still a two-person operation, and justifying the paperwork for the tax credit is harder.

Aesthetically, the pink fluff is angelic, whereas the Cellulose is a bit like a cave-dwelling, but nobody will ever see it.

Forget about any chances for a D.I.Y. project if you choose this type of insulation!

The Expanding Foam type of material is not the kind of thing you can learn as you go or fix your mistakes easily. Just the safety equipment and containment techniques alone put any untrained person in an incapable zone.

Unlike the other options for insulation, this stuff doesn’t easily move out of the way if you want to add a ceiling light or install a bigger bathroom exhaust fan. It glues itself to all the surfaces it touches. It can be sawed with the appropriate tools, but it’s far different than fluffy insulation being held in place by gravity.

A big advantage of spraying this into the rafters is it adds structural integrity to the roof, both the sheathing and the rafters. It also eliminates the need for ventilation because there is no way for vapors to intrude where it’s sprayed and turn into water droplets. The items called baffles are a way of keeping the air flowing for fiberglass insulation so water vapor doesn’t become a wet layer on the wooden sheathing & rafters. Another advantage is that since you don’t need ventilation, your energy savings are enhanced. In the summer ventilation lets hot outside air get inside the attic, and in the winter it lets cold outside air in there. Both seasons put temperatures near your ceiling that you don’t want there!

All insulation leaks energy to the other side, the R-Value just indicates how much it gets slowed down. If the temperature difference is smaller, the insulation works better. In this case of spraying the rafter area, getting rid of ventilation keeps the temperature difference smaller.

Why insulation works…

There are 3 natural ways that thermal energy changes places; convection, conduction, and radiation. Insulation nearly stops the convection problem. Convection is the motion of hot and cold air changing places. Conduction is when the hot atoms on one side of an object smack into the cold atoms next to them eventually making the whole object one temperature. Radiation is when energy was powerful enough to emit light, and when that light hits something it warms that thing up; see also E=mc².

Of the building materials we use, wood is a great insulator because conduction is slow, but solid wood walls are heavy, expensive, and hard to put wires and pipes through. Glass is a bad insulator because it conducts quickly which makes a person wonder how fiberGLASS could help. Well, a material we don’t build with but is always present is air. Non-moving air is a wonderful insulator, but moving air is a great heat exchanger.

This sketch illustrates how an uninsulated wall becomes a heat exchanger. The temperature of the outdoors is massive compared to our tiny indoor safe places, so the outdoors will always win.

The outer walls use conduction to bring the outside temperature to the inside hollow of the wall. Then if there isn’t insulation, it quickly causes a convection current to transfer that outside to the inner wall which conducts that temperature to the inside.

The fluffy materials we use to insulate basically just make it really hard for air to move. The actual fiberglass will conduct the temperature difference across the fibers, but because they are insignificantly small, the total transfer is not a big deal.

The same principles go on in the attic, but the geometry is different and completely filling the void would be ridiculously expensive.

Reckoning back to how I mentioned the itchy yellow fiberglass used during the initial construction tends to deteriorate over time, our walls can be upgraded, but that is a difficult operation. A professional insulator has to make holes in the walls to insert a blower for adding cellulose to the wall, then patch up the holes afterward. Depending on the situation is where they make the holes. If you have vinyl siding, they may pull off the top and bottom pieces to do the work. If you have brick, they might try going in through your drywall instead. This type of rework is best in walls that were never insulated.

Resources and other information…

Government / Authoritative Information

Materials Rough Estimates

Depending on the final R-Value you desire, a typical Harrogate Square condominium attic space that has never been updated should use between 15 to 20 units of the AttiCat Pink Loosefill or about 34 to 46 units of Greenfiber’s Sanctuary cellulose. Depending on the roof’s slope, the maximum thickness for loosefill along the edges of the ceiling near the gutters is 21″, if the baffles are up between the rafters as they should be, see the sketch below.

Ideal Conditions of Harrogate Square Roofing after the Upgrades 2017-2019

It won’t be a problem for most unit owners to get their insulation upgraded to an R-60 value. The yellow rectangle under the shingles in the sketch above represents the ventilation baffles, and the slope of the roof is 4:12, so the 4-foot long baffle (48-inches) raises up 16-inches, and add to that the 6-inch tall ceiling joist giving 22-inches total of insulation including the crummy yellow stuff from the 1970s (R-60 value) without plugging the ventilation baffle in any way. A couple of our roofs are only 2:12 sloped, so they would be filling 14-inches max (R-38 value, the minimum recommended for our area) at the edges. At least one Harrogate Square roof is 6:12.

Comparatively, one “FROTH-PAK Low GWP 620 Spray Gun Indoor/Outdoor Spray Foam Insulation” can’t even spray your full attic with a 1-inch layer (R-6.8 value) costing over $1,000.00 but, for under $600.00 of AttiCat loosefill you get to the R-22 value in your whole attic. Spray Foam is not a D.I.Y. task. It’s wonderful stuff, but leave that to the Pros.

Fun videos to see the work happening…

Expanding Spray Foam done by a local company

AttiCat Loosefill done by a competent person with no experience

This one is the DIY “How-To” under ideal conditions by Owens Corning Canada

This Old House uses novel techniques

Greenfiber Sanctuary cellulose “How-To” video by the company under ideal conditions

A professional contractor makes quiet rooms in the house by insulating the hollow walls

Techniques for dense packing a wall by the Greenfiber company

Instructional videos detailing the various insulation options…

What is the best Insulation? (Part 1)

What is the best Insulation? (Part 2)

Side-By-Side John Meeks Explains Cellulose vs. Fiberglass

Attic access holes and their problems…

Every unit pair at Harrogate Square seems to be different. Typically there’s one access hole per two units with a shared attic space. Sometimes neither has an access hole. Sometimes the access hole doesn’t actually give access, it just opens enough to peer through a crack. Some are in a place where it’s easy to put rolled insulation up into the attic and work as a simple D.I.Y. alone without machinery.

If you don’t have an access hole and your neighbor won’t let insulators go through theirs, or for some other reason, you can always have a new hole cut into some part of your ceiling. Most of these openings are in a closet. It takes some planning to find an ideal place to put one, and it doesn’t take much away from the aesthetics of the ceiling.

No matter how you add the opening, you must make sure the person doing the work has a good working knowledge of framing techniques and has physically inspected the shape of your unit’s roof from on top of the shingles. It’s possible to pick a spot, then after cutting through, you find the roof seems to have a roof on top of the roof where you picked and nobody can climb through your tiny new hole in the ceiling.

Bathroom Fans and ventilation fixtures through the shingles…

I haven’t found any pattern for which units are configured correctly and which aren’t. It seems that places that never got upgraded since the 1970s have 3-inch bathroom fan ports with no hose connected to them for upstairs bathrooms, and a 3-inch metal pipe from the first-floor bathroom up to the top of the ceiling joist along the firewall.

The standards today do not permit that situation. Fans are connected by hoses to a fixture that sends that warm humid air out past the shingles. The fixtures are relatively inexpensive, but sawing a hole through the shingles in just the right place to put it in so it never leaks is something to have an expert roofer do. Your insulation professional may have the skills to install the fixture and connect your fans to them.

Some people’s attics look all set except for the thickness of the insulation. That’s wonderful.

Two fixtures that I have noticed are consistently connected through the roof since the original build are the furnace’s chimney and the duct for the range hood over the stove (if the kitchen wasn’t radically remodeled by some unit owner). Google Maps recently updated the satellite imagery for Harrogate Square so you can zoom into your unit and see how many vent fixtures are on your roof. If you only see two on your unit, you’ll probably need one or more to connect your bathroom fans too.

The reason we don’t want warm humid air going up in the attic is it’s a great way to grow black mold on your sheathing and rafters, which almost goes without saying, lowers the selling value of your home. This problem is so pervasively common due to old building methods never being corrected over time that you shouldn’t be surprised if your insulation contractor asks you to pay for mold remediation prior to insulating.

Addendum

If you were to keep track of the difference between the amount you paid for the year before insulating, and the year after insulating, you can calculate the added value to the selling price of your unit with the following formula:

(Price Premium Over Comparable Units) = ((Last Years Energy Bills) – (This Years Energy Bills)) / (Current Average Mortgage Rate)

($26,400.00) = (($3,600.00) – ($2,280.00)) / (0.05)

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