Spray Foam
Spray foam insulation is one of the biggest advancements in the construction industry. It will make your building quieter, more comfortable and stronger while reducing your heating and cooling costs by up to 50%.
“Whether your building, renovating or developing your basement we encourage you to take a little time to read through our site. We promise that the time you spend learning about high performance insulation will be time well spent.”
This site is dedicated to educating consumers and construction professionals about the benefits of spray foam and to dispelling one of the biggest myths in the construction industry. The myth that R-Value ratings alone accurately reflect the real world performance of insulation products. Numerous studies and reports have shown that energy consumption can vary by up to 50% in buildings insulated with similar R-values but different types of insulation.
Why is insulation still rated according to R-value? The R-value rating system was developed more then 50 years ago and at the time it was the best we could come up with. Since then much more advanced insulation products have been developed and our understanding of building science has grown tremendously. So why hasn’t the R-value rating system been replaced with a more accurate rating system? Simply put building codes are slow to change and most consumers have been taught for many years that R-value is all that matters. For more information on why R-value is a misleading and somewhat meaningless number click here.
Our Services
Why Choose Spray Foam
High R-Value
At Polytech we only use premium quality open cell and closed cell spray foams.
Closed cell spray foam provides the highest R-value per inch of any building insulation. Our Closed Cell spray foam provides a long term* R-value of approximately R-6 per inch. Our Open Cell spray foam provides an R-value of approximately R-3.9 per inch. Unlike other types of insulation that may sag, settle or shrink over time, spray foam will not sag, settle or shrink and will maintain its rated R-value for its entire service life.
*Long term R-value known as Long Term Thermal Resistance (LTTR), is how all closed cell spray foams in Canada are rated. LTTR is a 5-year, aged R-value. All closed cell spray foams will lose some R-value in the first few years before stabilizing. While premium quality closed cell spray foams may provide initial R-values as high as R-7 per inch, the Long Term Thermal Resistance is closer to R-6 per inch.
Air and Vapor Barrier
In buildings with traditional insulation, such as fiberglass, a vapor barrier is required on the warm side of the wall and an air barrier is located on the cold side of the wall. This is because warm air holds more moisture then cold air. The purpose of a vapor barrier is to stop warm moist air from entering the wall cavity and condensing. Condensation will greatly reduce the performance of traditional insulation and cause mold, mildew and rot. The purpose of the air barrier is to prevent air from leaking out of the wall cavity to the exterior.
In our mixed heating/cooling climate the role played by air and vapor barriers becomes a little more complicated. Building code requires the vapor barrier to be installed on the interior of the wall. This is to stop warm moist air (from the interior of the home) from entering the wall cavity and condensing during the winter when the drying potential is most limited. The unfortunate reality is that this system just doesn’t work. Even a well installed polyethylene vapor barrier is full of staple holes, screw holes, electrical outlets, plumbing penetrations, ducts and construction damage. This allows warm moist air to enter the wall cavity and condense. In the summer this process reverses because the interior of the wall assembly is the cool side (particularly in air-conditioned homes) and the warm moist air from the exterior can freely enter the wall cavity where it has the potential to condense against the cool surface of the interior wall. Combine this type of system with an air barrier system such as Tyvek which also has thousands of small holes and penetrations and you have a system with a high probability of air leakage and moisture accumulation.
Closed cell spray foam eliminates this issue. It acts as a both an air and vapor barrier and since the foam is uniformly solid it resists the passage of air and vapor equally well in both directions.
Air Infiltration And The Stack Effect
Air leakage can account for up to 40% of the energy used for heating and cooling a typical home. It can occur through both air infiltration (movement of air into the building) and air exfiltration (movement of air out of the building). Pressure differences which cause air leakage typically result from wind pressure, stack pressure or fan pressure.
Wind Pressure is simply pressure acting on the exterior of the building envelope (walls, roofs, etc.) caused by wind.
Stack Pressure (also known as the stack effect) is caused by a pressure difference between the top and bottom of the house. Warm air in a house rises creating positive pressure at the top of the house and negative pressure at the bottom. As the warm air exits through air leaks at the top of the home, cold air is drawn in at the bottom of the home through cracks, crevices and air permeable building materials to replace it. The stack effect can create significant pressure and move large volumes of air through a building. In the summer the reverse happens when hot air outside of an air-conditioned house pushes down cold air from the ceiling and out of cracks in the basement.
Fan Pressure is also known as mechanical pressurization. This is pressure is caused by mechanical equipment and can create either positive or negative pressure inside of a building. HVAC systems can create positive pressure while exhaust systems such as a range hood, dryer or exhaust fan can create negative pressure.
When pressure differences exists between the interior and exterior there is an incentive for air leakage to occur. Spray foam greatly reduces air leakage. It acts as an air barrier and bonds permanently to the structure of the building. With spray foam insulation you can keep the air that you have paid to heat or cool inside of you home.
Lower Energy Consumption
Spray foam insulation can have a dramatic impact on your heating and cooling costs. Studies have shown up to a 50%* reduction in energy consumption (even more in certain retrofit applications).
*Source: pinnaclewest.net
Increased Structural Strength
Closed cell spray foam is rigid and adheres to both the exterior sheeting and wall studs. It essentially acts like glue and enhances the overall strength of the entire building. Research conducted by the National Association of Home Builders has shown that walls insulated with closed cell spray foam have up to 300%* greater racking and shear strength. This can be especially beneficial in high wind areas.
*Source: pinnaclewest.net
Increased Comfort
Perhaps one of the most understated benefits of spray foam insulation is the increased comfort and enjoyment of your home. Homes insulated with spray foam feel more solid, are quieter and tend to be more uniformly warm or cool. No more turning the heat or air conditioning down overnight to save energy.
Environmentally Friendly
Spray foam is one of the most environmentally friendly insulation products available. It can reduce heating and cooling costs by up to 50% in new construction and even more in some retrofit applications. Spray foam emits no CO₂ or ozone depleting agents, has no formaldehyde, is free of all HFAs, HCFCs, HFCs and will last for the life of the building. It also requires less energy to produce than other insulation products.
Superior Indoor Air Quality
Once cured, spray foam insulation has no emissions; it is chemically dead and poses no health risks. Unlike some types of insulation, spray foam is free of all HFAs, HCFCs, HFCs and formaldehyde. It can eliminate potential air infiltration and moisture problems that can contribute to mold growth. It even prevents external pollutants such as dust, pollen and vehicle exhaust from entering the building through air leakage.
Sound Investment Value
With savings of up to 50% on heating and cooling costs, spray foam insulation makes financial sense. While the initial cost of spray foam is higher than traditional insulation, it significantly reduces monthly energy costs. As energy prices inevitably increase, you will benefit even more from reduced energy consumption.
Making Sense of R-Value (R-Value Myth)
Thermal energy is transferred in three different ways: conduction, convection and radiation.
- Conduction occurs when energy transfers between materials that are physically touching each other, e.g. heat from a stove is transferred to a frying pan.
- Convection is the transfer of energy through the movement of a fluid or gas (e.g. air). For example, a hot cup of tea will cool off because its heat transfers into the air around it by convection.
- Radiation is energy transfer in the form of electromagnetic waves mainly in the infrared region, such as how the sun warms the Earth.
The R-value rated on insulation products measures only the resistance to conduction. It does not measure or account for resistance to convection or radiation. Why is this important? Because the majority of a buildings heat loss is through convection and air leakage while far less is due to conduction.
How does convection occur inside of an insulated wall cavity? Convection occurs when warm and cold air circulate within a wall cavity because of differences in air density. Warm air is lighter and rises (think of a hot air balloon) while cold air is heavier and sinks. As this air circulation occurs, energy is transferred between the interior and exterior of the wall. The greater the difference between the interior and exterior temperature the greater the convection. Introduce some air leakage and you have a system that will never preform well. Traditional insulation such as fiberglass can only slow down convection and does nothing to eliminate air leakage. Spray foam eliminates both convection and air leakage.
In the real world, wall cavities are not airtight nor is framing perfect. Some stud bays may be slightly larger or smaller and studs are often bowed, making it challenging to install conventional insulation effectively. Because conventional insulation does not bond to the substrate, the likelihood of the insulation material sagging over time is high. If conventional insulation is not properly installed around irregular framing areas or it sags in the wall cavity voids may be created. Even small voids of 1-2% can result in big energy losses. Spray foam expands to fill in irregular framing areas and bonds directly to the substrate creating a permanent barrier that will never sag or settle.
For an excellent demonstration of convection within a wall cavity, simply remove a cover from a plug or switch on an exterior wall on a cold winter day. The draft you feel coming out of the electrical box shows how much air is moving within the wall cavity.
Here is a video by Steve Maxwell that gives a good explanation on why insulation with similar R-values can have extreme differences in energy performance. The video does an excellent job of explaining conduction and convection and why R-value alone is a poor way to rate an insulation’s performance. It describes a project where 2 identical homes were built side by side. One home was built with traditional framing and R-20 fiberglass insulation. The other home with R-17 structural insulated panels (foam based panels). Both homes were monitored for a year to evaluate energy consumption. Spoiler alert…. The R-17 home used 50% less energy for heating and cooling than the R-20 fiberglass home.
Why Choose Polytech Foam
Quality Work. At Polytech Foam we pride ourselves in providing excellent quality spray foam installations with no mess left behind.
Quality Products. We use the very best open and closed cell spray foams on the market.
BBB Accredited. We are proudly accredited with the Better Business Bureau.
Get what you paid for. Some other spray foam companies have been known to short change their customers by misrepresenting the R-value of their product. How can they get away with this? To understand how a company can misrepresent the R-value of their foam you must first understand how foams are rated. Closed cell spray foam loses some R-value in the first few years before stabilizing. In Canada all closed cell foams are rated using their 5-year stabilized R-value. The foam will never lose R-value beyond this point. This is known as Long Term Thermal Resistance (LTTR) and is how all closed cell foams used in Canada are rated. The American rating system uses a 90 day R-value which is know as Aged R-value. The problem with this rating system is that the foam continues to lose R-value well beyond 90 days. This is why identical foams are rated approximately R-1 per inch higher in the United States than in Canada. Unscrupulous contractors have been providing American spec sheets to home owners and building inspectors for years. The client end sup getting less foam then they paid for and what the building code requires. These contractors often short change the customer even further by installing less foam thickness than they were paid to install.
Don’t be fooled by unethical contractors. At Polytech Foam Solutions we will never mislead our customers and we will always install as much foam as we have been hired to install. Complete specifications on all our products can be downloaded from the Links section of our website.
Is Spray Foam Safe?
Correctly installed spray foam is perfectly safe. Once cured, spray foam insulation has no emissions, is chemically dead and contains no health risks. Unfortunately, in recent years spray foam has received some bad publicity. Incorrectly installed spray foam can cause some serious issues including on-going off-gassing. These issues are typically caused by 2 main reasons:
- Incorrect mixing of the two chemical components. Spray foam is manufactured by combining two chemical components at a specific temperature, pressure and an exact ratio of 1:1. Polytech Foam uses the latest generation reactor and application gun from Graco. This is the most advanced system on the market. The reactor is designed to keep temperatures and pressures consistent and balanced. Any imbalance in the pressure which could result in an off-ratio mixture will cause the reactor to shut down. Correct temperatures and pressures are determined by the foam manufacturer.
- Excessive pass thickness may cause issues with the foam. All spray foam has a maximum acceptable thickness per pass . Closed cell spray foam is generally around 2” and open cell spray foam is generally around 8”. Spray foam generates considerable heat when the chemical components are combined. As a result, it is imperative that maximum pass thickness is never exceeded. In addition adequate time is needed between passes to allow the material to cool (typically 20-40 min). Excessive pass thicknesses or inadequate time between passes can generate extreme heat and burn the material causing potential off-gassing.
Polytech staff has been trained by the foam manufacturer. We are committed to providing a quality application in accordance with the manufacturer’s specifications. Frequent site testing is performed during the application process to verify the quality of the foam.
Spray Foam Applications
New Construction
Spray foam may be one of the best investments you can make when your building a new home, office or warehouse. It make your building quieter, more comfortable and stronger while reducing your heating and cooling costs by up to 50%. It will even reduce your carbon footprint and contribute to superior indoor air quality. Best of all the monthly saving on heating and cooling are usually more then enough to offset the higher initial cost of spray foam.
Spray foam doesn’t just benefit building owners in the wintertime either. Ive worked in many new construction buildings which were insulated with fiberglass batts and they have one thing in common. In the hot summer months they are unbearably hot and uncomfortable to work in. This is because of convection (which is not accounted for in the R-value rating system). Insulation such as spray foam virtually eliminates convection making buildings far cooler and more comfortable without the need to continuously run air-conditioning.
Renovations
Renovations are the perfect opportunity to upgrade your insulation and air seal your house. Planning a basement development, addition or whole home renovation? Give us a call, were happy to meet with you and discuss options on improving you homes efficiency and comfort.
Attics
Attics are a major source of heat loss in any building. This is because hot air rises and the highest point in the house is where the greatest air pressure exists. This may sound like a simplistic answer but its not. Most attics are full of air leakage points and loose a lot of heat due to air leakage because they are never airtight. In all modern construction, building code requires the use of a vapor and air barrier between the interior of the house and the unconditioned attic space. 6mm Polyethylene is most commonly used. Its purpose is to stop moisture intrusion and air leakage into the attic. The reality of this type system is that no matter how well this barrier is installed its still full of staple holes, screw holes, electrical outlets, pot lights, plumbing penetrations, ducts and construction damage. All these small penetrations combined allow massive amounts of warm buoyant air to leak out of the home through the attic. When this happens, cold air is drawn into the home to replace the air that’s leaking out of the home. This phenomenon is known as the Stack Effect and can waste a lot of energy while contributing to a noticeable draftiness inside the building. In some buildings the stack effect is so powerful a draft may be felt coming from plugs and switches. In extreme cases exterior doors may even slam shut by themselves. The solution is simple, spray foam your attic and stop air leakage.
Crawlspaces
A well insulated crawlspace can have a dramatic effect on the comfort and energy consumption of you home. This is often one of the least expensive and most beneficial upgrades a homeowner can make. Homes with poorly insulated crawlspaces tend to have cold floors in the winter, drafts and higher heating costs. Air leaking out of your attic will make the problem even worse through a phenomenon know as the Stack Effect.
Walls
In most buildings one of the largest sources of heat loss occurs through the walls from air leakage and convective heat transfer. Spray foam insulation stops both air leakage and convection which has a dramatic impact on comfort and energy consumption. Spray foam doesn’t just benefit the home in the winter either. In the summer you’ll enjoy a much cooler home without the need to constantly run an air conditioner.
Floors/Overhangs
There is literally no way of having warm comfortable floors above cantilevers and overhangs when they are insulated with fiberglass. Fiberglass insulation is intended to trap air and in order to have any performance at all it must be installed in a sealed cavity. I’ve seen too many homes with rooms above carports, above grade additions and cantilevers where the floors are insulated with fiberglass batts and covered with aluminum soffiting. In some cases I’ve even seen perforated aluminum soffiting used. This is madness! Air can pass freely through fiberglass insulation and when this happens the effectiveness of the insulation is reduced dramatically. The solution is to use the right kind of insulation.
Cathedral Ceilings
Vaulted ceilings are becoming more commonplace in modern construction because they look great and make the room feel bigger. The problem is they don’t always leave much room for insulation and can be very difficult to air seal. This can make blown in or batt insulation ineffective. The solution is simple, have closed cell spray foam installed to the underside of the roof deck.
Rim Joists
The rim joist is the point where floor joists meet an exterior wall. These areas are nearly impossible to seal properly with conventional vapor barrier. This makes them a primary source of air leakage in most homes. Poorly sealed and insulated rim joist cavities cause cold floors, higher energy bills and support mold growth. Spray foam expands to fill every gap and crack and creates perfectly well insulated and sealed rim joist cavities.
Basements
Developing your basement is a great but expensive way to add living space to your home. Why spend all that money to have a cool, damp, musty area? With spray foam your basement can be warm, comfortable and dry all year long.
Basements can be a real challenge to keep dry and comfortable, especially in the cold winter months. The earth surrounding your foundation is cold year-round which means it’s constantly drawing heat from your home. This is why an average basement can account for up to 40% of a homes heat loss. Along with moisture control this is the reason that basements tend to be cool and uncomfortable.
Most basements are framed with a 1-2 inch gap between the framing and the concrete. Fiberglass batts are then installed in the framing and a vapor barrier is placed over the batts. The vapor barrier attempts to stop moist air from getting into the cavity and condensing on the cold concrete surface. Installing the framing 1-2 inches away from the concrete keeps the insulation away from the damp concrete surface. This minimises wetting of the insulation which causes poor thermal performance, mold, mildew, rot and the common musty smell.
The unfortunate reality of this kind of system is that it is an absolutely terrible way of insulating a basement. Why? There are 3 main reasons.
- Vapor barriers do not stop moist air from getting into the wall assembly and condensing. Even a well installed polyethylene vapor barrier is full of staple holes, screw holes, electrical outlets, plumbing penetrations, ducts, construction damage and air leakage from poorly sealed rim joist cavities as well as gaps underneath framing and around windows and doors.
- The vapor barrier takes away the inward drying potential of the basement trapping moisture inside the wall cavity. While an effective bulk water management system may keep the basement from flooding it is virtually impossible to keep the concrete foundation 100% dry. Water can soak into the concrete foundation by means of capillary action (think of how a sponge soaks up water) through the footing, penetrations, cracks and anywhere water comes into contact with the concrete. This is a big problem because the only drying potential is inward (assemblies dry towards the warm side) into a wall assembly where it becomes trapped by an interior vapor barrier. This problem occurs even on new houses let alone old houses that have no damp proofing installed on the foundation. This concept of moisture entrapment is why above grade walls are built with vapor permeable house wrap on the outside of the wall (to allow moisture trapped inside the wall cavities to dry to the outside). In a basement where the only drying potential is inward the interior vapor membrane used with traditional batt insulation systems can cause big problems.
- Conventional batt insulation is more prone to sagging in basement applications. In above grade walls batt insulation is in contact with the stud wall framing on both sides, plywood on the exterior and drywall on the interior. With this type of application the batts are slightly compressed which helps to hold them in place and prevent sagging. In basements the framing is 1-2 inches away from the exterior concrete so the batts have no real compressive force to prevent them from sagging. Even small amounts of sagging can result in big energy losses.
What’s the solution? Closed cell spray foam is a full air and vapor barrier. It seals penetrations (stopping air leakage) and creates a thermal barrier between your foundation and living space. Spray foam also fills the space between the framing studs and the concrete making it impossible for moist air to contact the cold concrete, eliminating the risk of condensation. In addition, it stops convective heat transfer and will greatly reduce your homes energy consumption.
If you’re building a new home, we encourage you to start with an under-slab spray foam system.
Exterior Foundation
Using spray foam on the exterior of a basement foundation is one of the most effective ways to reduce energy loss through the foundation, protect against moisture problems, eliminate air infiltration and extend the life of the concrete. Unlike rigid foams boards which are sometimes used spray foam insulation will bond directly to the concrete keeping out water, air and insects.
Sound Proofing
Got noisy neighbours, a basement suite or just want nice quiet bedrooms? Give us a call. Were happy to discuss the exceptional sound proofing characteristics of open cell spray foam.
Flat Roofs
Flat roofs can pose real challenges for conventional insulation. The problem is the ability of the system to dry effectively. Most wall systems are designed to allow the moisture that inevitably gets into the wall to dry to the exterior. With a flat roof this isn’t an option. On the exterior of the roof is a water tight (non permeable) roofing membrane and on the inside is an non permeable vapor barrier. This type of vapor locked system doesn’t allow for drying and would pose great risk of condensation build up leading to rotting of the roof structure, poor insulation performance, mold and mildew.
For years the answer to this was cross ventilation. Leave a gap above the insulation and install venting on the exterior of the building. This allows outside air to flow above the insulation giving moisture a way out. What a horrible idea!!! At one point this may have been the only option. Cross ventilation may have been better then a vapor lock but this is a really inefficient way to insulate. Fiberglass insulation works by trapping air and in order to function properly it needs to be installed in an airtight cavity. Even minor air leakage can have a substantial effect on its performance, major air leakage can have a staggering effect. What do you think would happen if you built a house without installing plywood or building paper and just left the fiberglass insulation exposed to the outside world? The warm air that should be trapped in the fiberglass would diffuse into the environment immediately. This is the problem with cross ventilation. Warm air that should be trapped in the fiberglass rises (warm air is buoyant) and is vented to the outside. Introduce some wind and this becomes even worse. Add some air leakage through the interior vapor barrier and you have one of the worst roof systems possible.
Closed cell spray foam eliminates this problem completely because it is impermeable to water vapor and stops all air movement.
Sheds
If your planning on heating a shed or using it for more than just storage spray foam may be your best option. The interior will be much cooler in the summer and much easier to heat in the winter. Closed cell spray foam will also greatly enhance the strength and rigidity of the shed. We typically recommend 2” to 3” of closed cell spray foam for sheds so there is no reason for 2×6 framing.
Garages
If your planning on heating your garage spray foam may be well worth the investment. It will keep your garage cooler in the summer and save on heating costs in the winter. If you have a room above the garage spray foam will keep the floor much warmer than conventional insulation and acts as a barrier against harmful fumes and exhaust. If your garage is primarily used for parking or storage it may be difficult to justify the cost of spray foam insulation.
Cottages
Spray foam will greatly reduce your heating costs making your cottage more uniformly warm, quiet and comfortable in the winter months. In the hot summer months, your cottage will be cooler and more enjoyable. For occasional use summer cottages that aren’t heated it may be difficult to justify the cost of spray foam insulation.
Under Concrete Slabs
There are 2 brilliant uses for spray foam under concrete.
The first is sprayed over a gravel bed before concrete is poured. This is a great option for any residential or light commercial slab. Concrete is an excellent conductor of cold. Spray foam between the ground and the concrete will create a thermal break resulting in much warmer concrete. Compared to rigid foam sheets this is a far superior system. Here are 3 reasons why.
- Spray Foam is liquid applied and has no seams or gaps. It makes and excellent seal preventing moisture and soil gas intrusion. This is why spray foam can be used as part of a radon barrier system.
- Spray foam conforms to irregular shapes and the contours of the substrate beneath the slab. This eliminates the possibility of hollow spots and voids and makes installations around difficult areas simple.
- Spray foam is denser and stronger than foam sheets and will resist construction damage better than other products.
The second use is when bonus rooms are built under garages. These rooms are great because they are a relatively inexpensive way to add significant square footage to your home. Unfortunately they pose some challenges for insulating. When tradition batt insulation is used it requires a vapor barrier to be installed on the warm side of the insulation. This can trap moisture between the concrete and the vapor barrier. Because of this cross ventilation is required to allow drying to the exterior which is a terrible idea. See our section on cross ventilation to find out why. Closed cell spray foam eliminates the risk of moisture accumulation as the foam itself is a vapor barrier and is bonded directly to the ceiling (underside of the slab). This results in a much warmer room with no risk of condensation issues. For even better performance ensure the wall studs are at least 1.5” away from the exterior walls and continue the foam from the ceiling all the way down to the floor. The result of this seamless application will be a warmer and much more comfortable room without being damp or musty.
Offices
Just like all buildings offices can be expensive to heat and cool. They are often uncomfortably cold in the winter and unbearably hot in the summer. Spray foam is just as effective at keeping your office cool in the summer as keeping it warm in the winter. It make your building quieter, more comfortable and stronger and will reduce your heating and cooling costs significantly. It will even reduce your carbon footprint and contribute to superior indoor air quality.
Shipping Containers
When a surface becomes cooler than the dew point, moisture in the air will condense against the surface. Metal has a high thermal mass and is an excellent conductor of heat and cold. This is why metal structures always tend to have condensation issues. Traditional insulation systems that use batt insulation with a vapor barrier are a terrible idea for shipping containers. Its virtually impossible to keep moist air from getting behind the vapor barrier. Once there it condenses into liquid water and has no way of drying. This leads to rust, mold, rotting of wood framing and poor insulation performance. Rigid insulations such as XPS or EPS have similar issues. They are difficult to adhere, don’t provide an airtight seal and the likelihood of getting condensation behind them is high. Closed cell spray foam is the only insulation product that will adhere directly to the metal surface. As closed cell spray foam is a vapor barrier (when installed at 2” thick or more) and is bonded directly to the metal surface it eliminates the risk of condensation forming behind the insulation. It requires no framing and provides excellent thermal performance with minimal thickness.
Shops & Warehouses
Warehouses & Shops can be challenging to heat and cool effectively not to mention expensive. Spray foam can reduce heating and cooling costs while making your building quieter, more comfortable and stronger. It will even reduce your carbon footprint and contribute to superior indoor air quality. You may even be able to downsize HVAC equipment.
Radon Barriers
Properly installed closed cell spray foam is an integral part of a Radon Barrier System. Please visit our Under Concrete Slabs section for more information.