House Insulation

Understanding Air Flow to Improve House Insulation

While many home owners know they have inadequate house insulation, they probably don’t know where or how the air is escaping or entering the house. They probably also don’t know what can be done about it. Detailed information about how air moves in a home will help you pinpoint how air is escaping or entering from your home. If you are a housing developer, a consumer on the market for a new home, or just in the mood for some handy home renovations that will save you money, then SprayEZ has a solution for you: Expandable Foam Insulation Kits. These kits, once applied, act as an effective barrier for air that otherwise escapes (and is let in) through nooks and crannies, thus forcing your heating and cooling systems to work harder, and costing you more money in utility bills. SprayEZ provides the integral finishing touch on house insulation that makes your ventilation or forced air system work more efficiently, the way you want it to, the way it should.

Below is a detailed breakdown of the areas susceptible to air infiltration. These gaps limit your home’s air distribution efficiency. Also included is a description of how expandable foam insulation can help. Air control is a concern both for housing developers and consumers, because a lot of the insulation areas that expandable foam insulation can fix are dealt with in the building process, not as a finishing touch. Especially for air ducts, chases, wall top plates, and dropped soffits, it is on the shoulders of builders to utilize expandable foam insulation to bring house insulation up to the sustainable standards of 21st- century housing development.

To fully understand the complexity of air flow in a home, it is important to clarify some aspects of how hot and cold air move. Understanding these fundamentals will make it clear that standard home insulation is not sufficient for proper air management. The implication, of course, falls on the homeowner, who is then left with high utility bills and continued discomfort.

So what’s all the fuss about hot and cold air in the home?

General Air Flow

Imagine a standard two-story house with a basement, in winter, for example. The hot air produced in the home is less dense than the cold air outside. The air wants to move from the warm, low density areas to the cold, high density areas to create equilibrium in air density. Therefore, the hot air will try to escape the warm areas in the lower floors as well as the controlled air of the home, and integrate instead with the cold air outside. At the same time that warm air is escaping from the top of the house, cold air is leaking in from the bottom of the house. If your house is very leaky, you will notice a large temperature difference between the bottom and top of the house.

These same principles apply in the opposite scenario, of course. When your house is cool in the summer due to air conditioning, the air outside is warmer and less dense. This difference in density causes warm air to come in from leaks at the top of your house. At the same time, leaks let out cool air from the bottom of the home. Controlling air flow can be difficult for the home builder and home owner. Proper house insulation can help. How do you control the air? How many ways are there for it to escape the home?

What is the connection between house insulation and air control? 

Standard home insulation policy does attempt to deal with air control in new home construction. There are standard grades for insulation materials, and construction companies can decide which grade to use in their developments. What this means is that the basics of home insulation are completed by the construction company, usually with the “pink-stuff”, a fluffy fiber-glass compound that has been an industry standard for years. Standards for what a building company must provide in terms of insulation vary from province to province in Canada, or state to state in the United States. Fiberglass is still the standard insulation material, as is mineral wool and cotton. The obvious problem is that home developers do not legally have to build homes with an insulation standard that truly satisfies the buyer.

This leads us to the secret of air control in the home – those nooks and crannies. A lot is at stake when considering house insulation and the cost of utilities. Every area of the home has its own particular challenges when it comes to sealing off the little cracks that hot or cold air can escape through, and a product like SprayEZ Expandable Foam Insulation provides a comprehensive answer.

To see how much air is being lost through the cracks of your house insulation matrix, let’s consider a comprehensive run-down of problem areas throughout a conventional two-story home with a basement, starting from the bottom up.

Outdoor Faucets

Outdoor faucets also need your attention as a homeowner. You should know where your outdoor faucet is. It’s where you get the water that waters your lawn!

Just to re-iterate: older or unfinished homes are probably going to be a lot more work when it comes to home installation. Standards are rapidly improving for new home construction. Take for example, a product like SprayEZ Expandable Insulation Foam, a do-it-all insulation tool that is changing the housing industry for the better.

Now, of course, it is a major job to apply foam to all the beams and pipes and pipes in your house, or to support the fiberglass insulation pieces as they are installed.

As discussed in this basement section of your standard home, it is the hidden areas of air flow that are a major theme in housing insulation – you cannot see it, but you can feel it, and you are paying for it. These are the real areas to be informed about, because it’s very likely that they are the problem areas. If you do hire a professional to apply foam to the insulation, make sure they also check out any crawls spaces in your basement. These areas gobble up the cold air that you want during the summer, and over the winter they get clogged with warm air trying to escape. You want that cold or warm air to be working for you, not against you. These crawls spaces can be as large as a small room in between your basement and main floor and as small as little construction quirks sometimes leave a small isolated space off to the side. The older the basement the more likely you will have quirky crawl spaces to manage.

Basement Insulation

The foundation of a home is of utmost importance for air control. In winter, it is here that cold air sweeps in from the cold ground underneath the cement flooring to replace the hot air that moves incessantly skywards. Every home is different, so every basement is different, but whether it’s a finished basement or not, you will have lots to be concerned about.

Basement Pipes 

Take for example interior plumbing penetrations – do you know where those are in your basement? Can you see them? Every home is comprised of a series of complex networks of pipes and tubing – all in the interest of sending air around the house, or sending unwanted air and waste out of the house. This means of course that in these hidden areas of complex piping and tubing, there is unwanted air moving in areas that are not helpful whatsoever. It is wasted air, trapped in places you cannot see.

So, if you live in an older home or a newer home with an unfinished basement, you can probably see these pipes and the space that separates them from the basement ceiling. If you cannot see them because you live in a finished basement, then perhaps they have already been applied with foam. These pipes in your basement urgently need to have some foam applied to them, because air could be leaking from them. Don’t forget that these pipes exist behind every kitchen and bathroom in your house (not just the basement!), and that the connection between these pipes might not be solid. The pipes need expandable foam insulation.

Appliance vents are an easier thing to spot, and an easier problem to solve. If you do your laundry downstairs, you need to make sure that the vent is properly sealed to the outside. Just connecting the tube to the external vent piece is not enough, because that external vent piece might not be air tight.

Basement Walls

In new home construction, the exterior of the basement walls are insulated to reduce heat loss and create a moisture barrier. Insulating the exterior wall also saves space but not having to insulate the interior of the wall. In an already constructed home, insulating to the interior basement walls reduces heat loss and helps prevents insect infestation. Interior wall insulation does not create a damp-proof coating and the insulation could potentially get wet from poor foundation water drainage.  

Sill Plates and Rim Joists

Another hidden area of concern, like the beam insulation in the basement, is the sill plates in the foundational structure of the home. Sill plates are horizontal pieces of a wall onto which vertical beams are attached. Expandable foam insulation can be used to insulate the area between the concrete floor and the sill plate. Spray foam could also between the sill plate and the rim joist or on top of the rim joist to prevent air from flowing in from the ground. The rim joist is usually one of the leakiest parts of a home.

Crawlspace Insulation

Crawlspaces can be insulated in two ways. Crawlspaces can be insulated via the foundation walls. Alternatively, the floor between the crawlspace and the house can be insulated. The type of insulation depends on whether the crawlspace is ventilated or not. With an unventilated crawlspace it is best to insulate the foundation walls. An unventilated crawlspace must be airtight.

Windows and Door Frames

Another large source of outside area comes from your door and window frames. Usually window frames are so poorly insulated that if you stand inside during a cold winter day you can feel a big current of cold air seeping in. Don’t forget the principle of air flow discussed earlier: the air wants equilibrium, and you want to separate it. That’s the constant challenge. Window frames leakage is topped with expandable foam inside the gap between the wall and window frame. Window frames require insulation around the edges before the walls are put up – if you don’t do it then, you’ll be regretting it after one cold winter. However, wood panels around the window can often be taken off, insulated and then replaced. This applies to all windows in the house, not just the ground floor windows. The insulation needs to be as secure as possible, and that means applying expandable foam insulation around the edges of the frame. Low expansion foam should be used so as not to bow the woodwork, but to create an effective air barrier.

When it comes to doors, any door frame will usually develop little creases over time, especially by the sill (the bottom of the door frame). These creases will turn into slights, and a sturdy door frame turns into a leaky sieve for hot air to escape through all winter. Foam around the edges will actually permanently seal the structure, making it impossible for little creases to build-up in the first place. If you’re applying foam to an older frame, then you can have confidence that it will seal over any existing slits.

Second Floor

Here’s where questions about floors and ceilings get quite fascinating, and are of utmost importance to your satisfaction. As we get into higher levels of the home, we know that the heat is likely to be more prominent here than on the first floor or the basement. As such, control each and every crevice – this will be much more helpful. It also is an area where a lot of the problem areas for house insulation are visible, and therefore easier to tackle.

The last major consideration on most second floor homes is the unsealed chase between the first and second floors. Chases are often used for electrical or air ventilation systems built into the wall structure. Sealing them at connecting nodes is key, as is any connection through flooring, as we’re discussing now.

Furthermore, as you can imagine, air is very attracted to these little cracks that allow them to escape to the attic, so you need to be very careful that you get them all. Unsealed chases or air ducts are particularly common on the floor below an attic, and for this reason they most definitely need to be properly sealed. The challenge is to find them and get them all, because they are hiding behind your drywall. It is a fact that the only way for air ducts to work in conditioned spaces is for there to be an effective air barrier surrounding the ducts. This is exactly where expandable foam comes in handy, because it will whatever spatial requirements there are at hand, no matter if these spaces are of an odd shape, or if they change in odd ways. One last thing: chases don’t usually exist between the basement and first floor, so pay close attention to them on the second floor.


For obvious reasons, the attic and roof area represent one of the most challenging areas for air control in home insulation. In the winter, hot air rises to the space, robbing the home owner of what he or she is paying for. In the summer, hot air enters to and pushes out the cold air.

In attics that are unfinished, one can insulate between and over the floor joists. One could also insulate the attic door. In a finished attic, one could insulate between the studs of knee walls. Knee walls are the short walls under the slopped ceiling of the roof. One could also insulate the sloped ceiling. It is important to ask a building official in your township if spray foam needs to be covered with a layer of drywall. 

A lot of heat actually comes from the sun and over the summer months the sun is the real producer of heat in your attic. Heat from the sun that brings heat into the home is called radiant heat. Radiant heat is essentially the process of one object emitting enough heat to warm the objects around it. The sun is the most obvious example of radiant heat, while a fireplace is a more relevant secondary example. In home construction practices, radiant barriers are insulation tools that are used to reduce summer heat in attics specifically because of the radiant force of the sun. The sun naturally heats up the shingles on the roof, which then transfer that heat to the attic. Radiant barriers reflect thermal heat to keep an attic cool. A technical description of a radiant barrier is that it is a highly reflective material that keeps heat from transferring through the shingles on the roof and into the home. Spray foam does not serve as a radiant barrier. Spray foam helps protects attics from the forces of convection and conduction. Radiant heat barriers cannot be combined with spray foam insulation.

Spray foam helps manage conduction and convection in your home. Conduction happens when the hot roof shingles transfer heat to the houses walls and roof. Convection happens when the hot roofs transfer heat to surrounding air and warms the entire house. Spray foam keeps your home warmed in the winter and helps keeps the home cooler in the summer. However, spray foam may increase the temperature of shingles, causing them to overheat. Check the manufacture’s warranty for the shingles to see if they void the warranty if you use spray foam. 

Attic Piping

Vent stacks are the tubes through which waste gasses exit the home. They are a part of the drain-waste-vent pipe system of the home, which ensures that there is no smell or sound as human waste is carried away. These vent stacks need to have a vent attached to the top of the stack, and it should be self-explanatory why this stack should also be closely insulated. In a similar fashion to the heating ducts, these vent stacks need to be treated with foam insulation in every space where there might be a pocket for air to pass through. Since these stacks are quite long, there are a lot of areas where foam insulation is required.

The same goes for exhaust fan piping. Exhaust fans actually act more as ventilators than the vent stacks. These fans carry air throughout the house. The piping needs to be insulated. Proper house insulation would not be complete without it!


As you can see, house insulation is a complex procedure that, if ignored, ends up costing you in utility bills and continued discomfort. As has been explained in this article, there are a number of areas in any conventional home that are extremely ineffectual at controlling air flow. Specifically, being aware of the complex networks of piping and tubing is a good start, before making any conclusive decisions about treatment. It is recommended that you take a close look at this guide, and check up on all the problem areas listed here. If you do that, you will at least begin to understand your house insulation a little better.

It is important that the housing industry as a whole takes note of these problem areas in house insulation techniques. It should not be incumbent only on the home owner to fix these obvious problems in house insulation – and indeed, it appears as though building requirements are slowly taking note. Of course, it’s a two-way street between home builder and home owner, and future home owners will certainly have a fair share of projects to work in.

As an existing home owner, if you have any concerns about the control of temperature in your home, it is highly recommended that you begin researching which areas need re-insulation. The most convenient way to solve these issues is to call SprayEZ and seek their knowledge advice and expertise. As you can see from the contents of this article, there are at many areas in the home that would benefit from close inspection and additional insulation using expandable foam insulation. You will save money and enjoy a home with consistent and controllable air flow.