Warm Home Insulation

Insulation is very important when it comes to houses and buildings.  Fiberglass was the most common type of insulation until the introduction of the Polyurethane foam insulation system.  Polyurethane is known to be a closed-cell material ensuring that the indoors is kept free from air and moisture.

The process of installing this type of insulation is also very simple and does not require anything else to hold it in place.  The foam is sprayed into the walls or between the ceiling and the roof.  The foam then starts to expand to about 100 times its original volume, thus, making its way to all parts of the wall and leaving no room for air or moisture to seep in.  It can be installed even in the hardest places to reach without settling or shrinking.

This type of residential insulation is highly recommended by the US Department of Energy because of its energy efficiency.  Spray foam insulation has an R-value of 6 to 8 per inch, much higher than that of fiberglass which only has an R-value of 2 to 4.  This means that any heating or cooling equipment would not require as much fuel as it would need with any other types of insulation systems.  Polyurethane, once installed in between walls and ceilings, does not emit any harmful odors or fumes.  Its efficiency in sealing out moisture makes it impossible for mold and mildew to grow, thus, reducing the risks of allergies.  It is very effective in keeping bugs and rodents out as the spray foam material has no food value for them whatsoever.

The great thing about spray foam insulation is that it actually adds to the structural strength of a house or building without adding too much weight to it.  So regardless of what material a house is made of, polyurethane spray foam insulation will adhere easily and work efficiently.

For more information about Spray Foam and how it can work for you, contact EcoLogic Spray Foam Insulation at 1 888 880-8420.

Tags : benifits, building envelope, efficiency, R-value
Posted in : Common Questions, Environment, R-value | Comments Off

Insulation foremost to efficient building

Today, common Insulation creates moisture problems

We must adopt modern, efficient insulation materials.  Insulation material in Canada needs to be updated to effectively protect our homes and reduce our energy dependency.  Canada’s often-humid climate is characterized by high humidity throughout the year in places. The effect of this climate on buildings and residential housing in particular is significant.  Moisture drive is the main issue though the seasonal temperature range exceeds 40 degrees Celsius (80 degrees in places) and contributes to structural damage and energy consumption over the course of the year.

Canadian homes are almost all insulated with fiberglass insulation though recently other fibrous materials such as cellulose and mineral wool have made inroads to the market.  Insulation in Canada must provide protection from moisture drive as well as thermal protection because of our climate.  In Canada, insulation needs to perform as an air barrier and a vapor barrier.  While traditional walls are built with air barrier and vapor barrier layers to protect the fibrous insulation, these have resulted in costly damage on an enormous scale in Canada’s climate.  Either because of poor installation, failure to seal with caulking (in older homes), post installation penetrations placed in the wall by homeowners or failure of the sealants over time, this technique fails to stand up to the environment.

Modern insulation is more costly to install, but save far more money in time.

Insulation in Canada is cheap and readily available and most homeowners give it little thought because it is so widely accepted that insulation comes in plastic bags and is pink in color.  This ready acceptance needs to be challenged for in Canada, pink insulation is responsible for water damage from water ingress, vapor drive from the interior side of the wall and the resultant mold and mildew issues that this soon to be trapped water creates.

Spray Foam Insulation results in energy efficiency, and healthy indoor air quality.

Homeowners need spray foam insulation in Canada and need to familiarize themselves with its cost, benefits and limitations for no other product can withstand the high humidity of our climate.  Spray foam insulation in Canada provides an air barrier/vapor barrier and thermal insulation in a single application.  Spray Foam insulation is made of billions of tiny plastic wrapped bubbles which are not subject to air movement or moisture drive, making it the very best insulation material for Canada cold climate on the market.  While more expensive to install, spray foam insulation results in lower utility bills, less structural damage over the life of the building, longer building life and a far lower overall ownership costs than fibrous products.  Be sure to ask how EcoLogicfoam insulation can meet your needs.

Tags : air quality, air tight, benifits, building envelope, moisture, R-value, renovating, spray foam insulation, thermal insulation
Posted in : Common Questions, Environment, R-value, building envelope | 6 Comments »

Spray Polyurethane Foam Insulation

Why Spray Polyurethane Foam Insulation?

Spray Polyurethane Foam Insulation (SPF) addresses the three main deficiencies in todays building insulation  – low whole wall R-Values, moisture damage due to vapor permeability and air tightness.

Insulation is used to stop heat loss and conserve energy, but todays materials fail to do an effective job of this on several counts.  Heat is lost in three ways, radiation, convection and conduction.  Of these, convective heat loss (movement of air – and heat with it from one area to another) is the most significant accounting for 60% of total heat loss.  Conduction accounts for another 32% with radiation responsible for the remaining 8%.

Spray Polyurethane Foam Insulation eliminates convective heat loss.

Convection occurs within your walls because of the thermal gradient across the wall assembly.  On the warm side of the wall, air is tends to rise and on the cold side of the wall, air will sink where air movement is not prevented.  This readily occurs in fibrous materials in conventional wall assemblies.  Spray Polyurethane foam insulation, however, eliminates convective heat loss because of its closed cellular structure preventing the movement of air through the material.  In doing so, it entirely eliminates the most significant source of heat loss in the thermal envelope.

Conduction is addressed by the measurement of R-Value.  In as little as 3.3” of closed cell SPF, an R-Value of R20 can be achieved reducing conductive heat loss exceeding the performance of 6” of fiberglass.

While neither fiberglass nor closed cell SPF addresses radiation, the effective whole wall performance of a closed cell SPF wall assembly will significantly outperform today’s fibrous materials by a considerable margin.

Protect your home from moisture damage with Spray Polyurethane Foam Insulation.

Moisture damage occurs due to vapor drive, condensation and water ingress.  Key to eliminating vapor drive is the use of a vapor impermeable material.  While 6 mil poly perfectly installed, completely sealed at top and bottom plates and transitions can serve as such until it is penetrated, poly fails when even small punctures are made in the product.  It is estimated that a one square inch hole allows as much moisture through a wall annually as 300 square feet of diffusion!  Because closed cell SPF is several inches thick, sprayed against the outside wall and bonded to the substrate (sheathing and studs), it forms a complete seal, not easily damaged by penetrations for wall hangings and electrical boxes.

Condensation is eliminated with Spray Polyurethane Foam Insulation.

Condensation occurs when a body of air is cooled sufficiently to condense moisture in the air mass.  Inside your walls, this occurs at the point in your insulation where the air becomes saturated.  If this occurs in todays fibrous products, moisture is deposited in your walls and can, over time, cause damage.  Closed cell SPF on the other hand does not breathe.  With the condensation point occurring inside the mass of SPF, there is not opportunity to deposit moisture eliminating this source of future damage.

Water ingress, regardless if it is due to a failed roof membrane, condensation or vapor drive requires that moisture be permitted a channel to escape.  A wall can dry to the interior or exterior but it must dry.  With SPF sprayed to the outside of the wall, and no poly sheathing on the inside of the wall, SPF provides readily available drying potential to the interior and a safer assembly than traditional fibrous products covered with 6 mil poly on one side and house wrap on the other.

Create an air tight home with Spray Polyurethane Foam Insulation.

Finally, closed cell SPF results in a very airtight structure.  While this requires the installation of mechanical air handling equipment to ensure sufficient fresh air supply, the mantra “seal it tight, ventilate it right” is the best rule to follow.  By providing direct control of air leakage, we can control air turn over and reduce heat loss due to ad-hoc seepage through wall assemblies.  Cost offsets can be found in downsizing  HVAC equipment due to lower natural air turnover.

By relying on traditional materials a home will consume as much as 50% more energy than is possible by installing closed cell SPF.  A wall assembly built with closed cell SPF reduces moisture related damage and therefore cost of ownership and increased air tightness improves on long term thermal performance as well as providing opportunity for cost offsets by reducing the size of mechanical equipment.

The long-term cost of this decision far outweighs the additional expense of upgrading to closed cell SPF.  This is to say nothing of the increased comfort in:

• Climate control.
• Quieter walls.
• Less dust.
• Increased structural rigidity.

Closed Cell Spray Polyurethane Foam Insulation is the next generation in high performance thermal barriers.

Closed cell SPF is the next generation of insulating material.  While more costly up front, the long term financial return when energy savings are accounted for results in significant savings over todays fibrous materials.  By reducing moisture related damage, increasing efficiency and comfort, Spray Polyurethane Foam is the solution to todays increasingly demanding building codes and energy conscious home owners.

Tags : air tight, benifits, building envelope, conduction, convection, energy efficient, moisture
Posted in : R-value, Return on Investment, building envelope | 7 Comments »

Building Insulation: a range full of choices

The process of building your home is an exercise in making decisions. From flooring to exterior siding, there are countless decisions to make before your home is complete and choosing your insulation is no different.

Insulation serves to conserve your energy consumption, lower your heating bills, increase your homes comfort and protect your home from the effects of condensation and the mold and mildew that can result.

Insulation, a short history

Insulation comes in many forms. For the last 50 years fiberglass batts have been used almost to the exclusion of all other materials. Prior to this a variety of materials from saw dust to newspapers where used. Today, there are greater choices than ever before including Mineral wool (Roxul), dry packed or wet cellulose, recycled blue jean batts, rigid foam boards and spray foam insulation in the form of open cell or closed cell polyurethane.

Each product comes with its own advantages and disadvantages. In order to determine which product you want to install, we need to look at what you want to accomplish and what insulation is supposed to do for you.

Insulation, key to your building envelope

When it comes to the science of building construction, your building envelope and your thermal envelope are both important concepts to understand. Your building envelope is the exterior perimeter of your home including its walls and roof. Your thermal envelope is often but not always the same as your building envelope. For example, in most conventional homes, fiberglass is laid on the floor of your attic. In this case your thermal envelope is the ceiling of your home as that is where the insulation lies. Because it is not co-located with your building envelope (roof) this can create problems but we will get back to that in a moment.

For the most part your building envelope and thermal envelope work together to create a system which prevents air, water and heat from moving through your homes walls. This is traditionally done using a variety of materials. We will use fiberglass as an example as it is so widely accepted. Fiberglass, when looked at closely, is strands of spun fibers grouped together into batts. These fibers are densely packed enough to slow the movement of air through it, though it does not stop the movement of air. Stopping the movement of air through your walls is key, for air carries with it moisture in the form of humidity and there is no force more destructive to building materials. What you end up with is an assembly of materials working together: fiberglass maintains a temperature difference across the wall assembly and 6 mil poly (vapor barrier) is used to prevent the movement of air and moisture through the fiberglass.

Problems arise when the 6 mil poly is imperfectly installed or subsequently damaged by hanging pictures,curtains, installing retrofit electrical outlets, recessed lighting etc. Any time a cut or penetration is made through your 6 mil poly, you have introduced a pathway for air and moisture to move through your walls. This occurs not only because of damage but also because even when poly is perfectly sealed at the time of installation, that sealant will tend to release over time allowing air and moisture to move through the assembly. This same problem occurs with any material that does not form an air barrier and vapor barrier – cellulose, roxul, jeans, etc. All of these products rely on polyethylene vapor barriers to prevent moisture ingress.

Spray Foam insulation, stands alone as a vapor barrier & Air Barrier.

Spray Foam alone, because of its vapor barrier and air barrier properties does not require 6 mil polyethylene sheets. Because spray foam is installed at three inch depth or greater, it is not going to be penetrated with nails or screws and is not subject to release from the substrate over time. In doing so, it provides a perfect air barrier and vapor barrier and a higher R value than any other material available.

Spray Foam Insulation prevents convective heat loss

Lastly, spray foam insulation eliminates convective air movement inside your walls. Because all other materials simply slow the movement of air through them they are still subject to convective heat loss. This is the reason for the enormous depth of loose fill fiberglass required by code in most attic spaces. With foam, you get an air barrier because foam does not permit air movement through the material and in so doing eliminates 60% of all heat loss immediately. The result is a higher thermal efficiency and substantial energy savings over all other materials.

While spray foam insulation is more expensive than all other choices, you will see the cost returned to you over time in as little as 5 – 6 years. Beyond that, spry foam is the cheaper solution.

If you would like to discuss your spray foam needs, contact EcoLogic Spray Foam insulation today at 1 888-880-8420.

Tags : benifits, building envelope, energy efficient
Posted in : Environment, building envelope | 13 Comments »

cost of home ownership

The High cost of Home Ownership

This week, I have a personal story to tell as it taught me something new.  Some very good friends of ours are in the process of building a home.  This home is larger than any I ever aspire to live in, at over 7500 square feet.  Being built in South Langley, it is in the premiere development in the Fraser Valley where lots run well into 7 figures.

This home is surrounded by multi-million dollar homes and when finished will join them with a similar valuation.  The finishes are outstanding, the view incredible, little expense is spared from granite to Appliances, fixtures to finishes.  As I indicated, these are good friends and I offered to install our soya based spray foam insulation for what is essentially cost because first I wanted them to have the best and I wanted to help them where I could and second because I wanted to showcase our product in a market where it makes sense to spray foam.  7500+ square foot homes are costly to heat!

Cost of Home Ownership impacted by Insulation Choices

I was more than a little surprised when our friends turned down my offer.  Far from being hurt, I could not understand why they would not take advantage of a once in a lifetime opportunity to save on the size of their furnace, the air conditioner, their HRV, their on-going energy expenses!  Why they would not want to reduce the amount of dust entering their home, the noise that penetrates the walls, or enjoy the comfort that comes from a home that is insulated with spray foam.

It has taken some time, but I have come to realize that no matter rich or poor, we all tend to look at money in relation to time.  The true cost of home ownership is never accounted for.  The total cost of home ownership is never really considered.  While spray foam is considerably more expensive than fiberglass batts, these are up front costs, while this decision has an everlasting impact on the ownership costs, specifically impacting utility bills and maintenance.

Fiberglass negatively impacts the total Cost of Home Ownership

I urge you to consider the math of installing a cheap and inferior furnace filter as an insulator (fiberglass) instead of an air tight, vapor barrier and thermal insulator in spray foam insulation.  Your cost of home ownership with spray foam including up front installation and utilities meet the cost of owning a home with fiberglass in between 5 and 6 years, after which you are saving money with spray foam.  Yes, it is the cheaper solution in as little as 5 years!

Another item that I find people often overlook is how air tight their spray foamed homes are.  The mantra “seal it tight, ventilate it right” describes a sound way to build.  By spraying your home, you air seal your building envelope resulting in near zero seepage.  This means that your furnace can be downsized, as can your heat pump, geo-thermal unit, air conditioner, and air filtration system.  There are significant savings to be had here.

If the decision to use foam is made at the planning stages, there are additional savings to be made using modern framing techniques because foam increases your shearing strength by three fold.

The cost of home ownership is also impacted by maintenance.  Because foam eliminates moisture ingress, maintenance due to water damage is virtually eliminated.

Fiberglass increases the total cost of Home Ownership

In so many ways, foam is the cheap alternative to fiberglass which results in high energy bills, poor performance, oversized HRV equipment, potential moisture damage and increased maintenance costs.  How do you look at the cost of home ownership?

Tags : benifits, building envelope, Cost, heat loss, moisture, return, spray foam insulation
Posted in : Cost, building envelope | 3 Comments »

Comfort provided by spray foam

Spray Foam Insulation problems, Depth control

Spray foam insulation is perhaps the most significant new building product on the market.  Amidst all the hype of green materials, LEED certification points and environmentally friendly new products, spray foam insulation alone stands out as the biggest game changer in the push to build more efficient homes.  The results are home that consume 50% less energy to heat them, are far more comfortable and have better indoor air quality.

Spray foam and the Building Envelope

Properly applied, spray foam insulation creates a continuous building envelope with no gaps or cracks through which air and moisture can enter or escape, but problems arise when spray foam is not properly installed.

Spray Foam generates heat

When installed, spray foam is applied by mixing two highly reactive materials in an airstream as they leave a spray gun.  This reaction creates heat as it forms bubbles and rises to form foam.  This heat will escape as the foam cools and a good installation allows the foam to cool fairly evenly.

Properly installed foam is applied at a depth not greater than 2” deep.  This allows the foam to cool reasonably consistently from the outside, in.  When foam is installed at greater depths than this, it cools unevenly.  The interior core of the foam will remain hot long after the exterior has cooled.  This creates stress within the foam and can result in foam that pulls away from the wall or studs and even foam that cracks.  When this happens, it is not generally seen as a small shallow crack but a deep fissure to the core of the material.

A good spray foam installer won’t take short cuts

There are several reasons that a foam installer may apply a layer greater than 2”.  These reasons may include inexperience, but more likely are a result of commercial pressure to increase the yield of the material, which can be achieved by applying it in thicker layers.  If your contractor has under bid the job and wants to stretch the material he installs he can accomplish this by laying foam a little deeper.  This is contrary to the CAN/ULC 705.2 specification which details how foam is to be installed.

Some products are to be avoided

While not common, there have been a number of incidences in Eastern Canada with a product introduced this past year, which have resulted in house fires that have burned the structures to the ground.  This has resulted when a significant depth of a competitors foam product is installed at once and the trapped heat in the interior of the material cannot escape and eventually combusts.  This is not common and yet it also points out the importance of knowing what product is being sprayed.

While it is difficult to monitor your foam installation because the installation process requires WorkSafe safety gear be worn, hiring a reputable installer who can supply references is a good first step.

Please feel free to contact EcoLogic Spray foam to discuss any questions you may have.

Tags : building envelope, Questions
Posted in : Common Questions, Environment, R-value | Comments Off

Is your home sealed too tight?

Here’s a conundrum:  Modern Canadian homes are too tight?  But efficient homes have to be tight by definition.  Following is a brief look at the issue, the problem, and an effective solution.

Traditionally, homes were made to breathe, not sealed up air tight.

Traditional Homes in Canada stood the test of time. They were not terribly well insulated, not very efficient, not immune to water ingress and yet they were fairly healthy to live in, they withstood the elements and they lasted a long time.  Modern Canadian Homes on the other hand, are very efficient, are well insulated, include products to manage water ingress and eliminate air movement through walls and as a result are much tighter.  As building techniques have changed though, occupants and architects have found that modern buildings in Canada do not always create healthy living environments, are often subject to water damage and tend to incur higher maintenance costs and have shorter life expectancies.  What has happened and what can be done?

At issue is moisture.  In Canada, moisture is responsible for most structural damage to wood frame buildings.  It is primarily responsible for reduced indoor air quality, it is required for the growth and spread of mold and its damaging effects to both buildings and occupants and it results in shorter building life spans and higher building maintenance costs.

Energy Efficiency requires air tight buildings

The problem is that whereas older buildings were designed and built fairly porous, modern buildings are built tight to seal in heat energy.  The result is that older Canadian buildings naturally got wet and then dried while modern buildings still get wet in spite of 6 mil polyethylene vapor barriers, but they do not dry!  This trapped moisture is the source of rot, and mildew, and is the cause of most structural damage, mold growth, poor indoor air quality and high maintenance costs.

A typical modern wall assembly

To look closer at how a modern Canadian home is built we need to look at how its wall assembly is created.  This typically includes 2×6 wood framing members with fibrous insulation batts fitted in the cavity between them.  On the indoor side of the framing is a 6 mil polyethylene vapor barrier, drywall and paint.  On the outside of the wall we generally find OSB sheathing, a house wrap and vinyl siding.  The purpose of the vapor barrier, and the house wrap layers is to protect the porous insulation in between them from air movement for air carries with it moisture.

The entire assembly is designed to assist the fibrous insulating layer in its job and to protect it from getting and staying wet.  In doing so, any moisture that does get past them through penetrations or inadequate sealing at transitions becomes trapped.  What is required is to replace the insulating layer itself with a material that prevents the flow of air and moisture through it.

The answer: An Air tight seal that does not permit moisture to accumulate.

If the insulating layer itself is impenetrable to moisture than there would be no space for moisture to accumulate and all of the issues with modern Canadian homes would be addressed in a single application.  There would be no water damage, mold growth, poor indoor air quality, higher maintenance costs or reduced building life expectancy and we would have well insulated, highly efficient buildings to boot!

The only product that possesses the properties and capability to achieve the required moisture barrier in Canada is medium density (2 Lb) spray foam insulation.  Sprayed in place it is perfectly fitted to completely fill even the tiniest gaps and cracks in the wall assembly.  Spray foam insulation is a recognized air barrier and vapor barrier by the Canadian Construction Materials Center.  Spray foam insulation is one of the most rigorously tested materials that goes into homes.  It does not off gas after installation, it is inert, it will not settle or sag, it is rigid and increases the racking and shearing strength to a home by 300%, it has an R value of twice fiberglass in a given depth or thickness of material and while more costly to install it reduces the total cost of ownership by reducing energy expenses, maintenance costs and eliminating water damage.  The soft cost of improved indoor air quality and occupant comfort alone are enough to justify the additional cost.  Spray foam is becoming far more widely accepted in Canada by homeowners who increasingly understand the importance of moisture control in the health of their homes.

The answer is to seal it tight and ventilate it right.

Tags : air quality, air tight, building envelope, moisture
Posted in : Environment, building envelope | 5 Comments »

Fiberglass – that fluffy, pink, insulation.

fiberglass

Home insulation.  It is pink, right? It comes in big oblong shaped bags and bursts out of them as they are opened – it is precut to fit into your walls perfectly and it has the claimed R-Value printed on the outside of the bag so you know what you are getting.  Home builders have been using it for decades now – it is fibergalss and is the standard, the norm and the dominant product on the market.

Fiberglass, it comes in loosely woven batts – cut to shape, made up of millions of tiny little strands of spun… glass!  No surprise there as it is in the name, but glass – isn’t that what our windows are made of – and aren’t windows a source of heat loss because glass conducts heat energy so well?  So why do we have it in our walls to keep our homes warm?  Oh ya, it is not the glass itself but the air that it traps in between the glass fibers that acts as an insulator.  Because that air is held in place and does not move, it maintains a different temperature than the air beside it.  But…  how does a fiber hold air in place?  It can’t.  So then air is not held in place, it is simply slowed in its movement.  That must be it right?

Is fiberglass effective?

But if air is simply slowed down, how is it an effective insulator if it can move from place to place?  Does it move, or is it simply that it can – I mean it is inside a wall, after all.

Air not only moves through fiberglass, it does so readily, quickly and systematically, acting in response to the laws of physics.  If you were to draw a wall (which is an assembly of different products) in profile, you would see that the majority of space in that wall (between the studs) is occupied by our fiberglass insulation batts.  On one side of the wall is our indoor room, and on the other is the outside world.  Our wall keeps them separate if it is doing its job.  Most of us know that warm air weighs less than cool air and thus tends to rise.  In Canada, in the winter time, our homes are generally kept at a comfortable 23 degrees celcius, while the outdoor environment can be anywhere from 0 degrees celcius in coastal areas to -40 degrees on the prairies.  The effect of this is that the air (loosely held in our fiberglass batt) that rests against the outside wall is cooler than the air that rests against the indoor wall.  Because of this the air against the outer wall tends to fall through the insulation and the air against the inside wall rises.  A convective current is formed and this is an effective heat transfer mechanism which moves heat energy from the inside wall to the outside wall and into the environment.  Fiberglass is a poor insulator.

Does fiberglass perform?

Further, while there is a vapor barrier in the form of a 6 mil polyethylene sheet on the inside of the wall which theoretically prevents air from moving into the wall, there is none on the exterior of the wall.  The result of this is that wind pressure can easily penetrate into the wall assembly and move through it.  As it does so it transfers heat in the air trapped in our insulation to the outdoors.  Fiberglass needs to be protected from air movement and this cannot be done on both sides of the wall.

Is fiberglass resilient?

What about the durability of fiberglass.  Those batts we install are not very rigid.  They are actually kind of floppy and need to be placed fairly carefully in order to get them to stay before we put up the vapor barrier.  What happens to them behind our walls over the years – do they stay in place, or settle.  Even worse, what happens if they get wet somehow – do they tend to sag and lose their insulating properties or leave areas of our walls uncovered and unprotected from the cold (and water damage).  Fiberglass is not durable.

Is fiberglass safe?

We haven’t even looked at the effect of having glass fibers in our homes.  Tiny glass fibers are not friendly to people.  If you think it’s a reasonable proposition that inhaling microscopic shards of glass coated with phenol-formaldehyde and urea-formaldehyde resins can cause disease, I’d say that we do not want fiberglass in our homes.  Fiberglass is not safe.

Spray foam replaces fiberglass – it does the job fiberglass fails to.

What we need is a product that is effective, durable, safe, and not suceptable to wind pressure, or moisture ingress.  While there are other insulating products on the market such as mineral wool, cellulose, even recycled blue jeans, Spray Foam Insulation stands alone in addressing each of these issues for it alone is not made of fibers, and is impervious to air and moisture flow.

Fiberglass days have passed.

Tags : air tight, benifits, building envelope, Cost, renovating, thermal insulation, Video
Posted in : Environment, Video, building envelope | 5 Comments »

Vapor Barrier

The wall assembly and moisture

Poor moisture control is responsible for the majority of structural damage to our homes wall assembly.   Moisture ingress into the wall assembly and its subsequent accumulation must be kept to a minimum for a buildings long term performance.  A wall assembly is designed to separate two unlike air masses – the internal from the external.  With careful planning, this can be accomplished but the majority of existing buildings, especially our homes, leak - outdoor air seeps into the wall assembly or even interior conditioned space, and conditioned interior air escapes and with it the heat, humidity control, and air purifying dollars spent to make our indoor environment ideal.

Penetrations in the wall assembly

Air movement through a buildings wall assembly happens because typical wall assembly seen in residential buildings are full of penetrations, utilize fibrous insulating materials, or are inadequately crafted.  This is accelerated where pressure is applied in the form of wind washing, large temperature differences across the wall assembly or as a result of vapor pressure differences.

A typical wall assembly is created (in Canada) with cladding on the outside of 2×6 structural framing with house wrap (Tyvek), and OSB in between.  The cavity is filled with fibrous insulation and the interior side of the framing is covered with 6 mil polyethylene layer and gypsum wallboard.  There are a number of potential problems with this construction.  First off, with the vapor barrier on the internal side of the wall assembly there is very little protection afforded to the fibrous insulation from exterior pressures from wind washing and convective currents created due to temperature differences across the wall assembly.  This means that exterior air has free access to the insulation in the wall assembly which itself allows air to move through it (fiberglass also doubles as a furnace filter – something you WANT air to move through)!  The result – a wall assembly that performs at vastly degraded real world R-Values than advertised.   The same thing happens from the interior side in a home that is pressurized.  Indoor, moisture laden air is forced through gaps, transitions and inadequately sealed junctions in the wall assembly into the cavity insulation and with it the energy used to condition it.   The main problem with this, aside from the immediate energy loss, is the moisture that this air carries with it.  When warm, moist air from either side of the wall reaches a sufficiently cool surface (from the cold outside in winter or through the use of air conditioners in summer), a condensing surface is formed allowing moisture to condense, accumulate, cause water damage, permit mold growth and lower the air quality of the home.  This is where a 6 mil polyethylene vapor barrier actually works against the building envelope by preventing the wall assembly from drying.  Because fiberglass allows air to move through it, and air moves moisture, water is going to get into a fiberglass insulated wall – what is then needed is a way for the water to get out – this cannot readily happen when vapor retarders such as polyethylene are used.

Spray Foam creates a better wall assembly

A better wall assembly is built when using medium density spray foam insulation such as EcoLogicFoam.  By forming billions of tiny bubbles made of thin plastic walls, it is impervious to moisture flow (recognized by the Canadian Construction materials Center as an air & vapor Barrier) and does not allow water to accumulate inside of the material.  Further because it is a continuous insulator, the surface of the foam never becomes a condensing surface on either the interior or the exterior surface meaning that any moisture laden air that comes into contact with it cannot deposit or accumulate that moisture on the surface of the foam.  This alleviates the pressure driven movement of both air and moisture through the wall assembly and results in a tight envelope that permits the conditioning of the interior environment with a high degree of efficiency through conservation.

In our next instalment we will examine the cost of using spray foam insulation verses typical fiberglass batts in a wall assembly.

Tags : air tight, building envelope, convection, moisture
Posted in : Environment, building envelope | 58 Comments »

Apply spray foam here

There has been a long standing debate about home construction and how to build good, sound, safe, healthy homes.  Over the last half century, homes have become increasingly air tight as mandated by changes to building codes.  This has caused a number of issues in building envelope performance and has stoked the ongoing debate.

Long standing, experienced home builders advocate a home that naturally breathes as being healthier.  Allowing a home to naturally breathe allows any moisture that accumulates inside the walls or attic space to naturally exit as it evaporates over time back into the air column around it and is then carried out through soffets, transitions or simply through a semi permeable wall assembly.

With increasing energy costs and consumer awareness of energy efficiency, homeowners are calling for more efficient homes and builders and code officials have responded with tighter envelopes.  In an increasingly energy conscious world, it makes no sense to simply allow a building to leak air naturally when we have to spend an ever increasing amount of money to heat and cool our homes.  Since we have the technology to make homes more efficient, we should.  Any concerns about moisture accumulation can be handled by mechanical equipment and maintaining humidity in an acceptable range.

With the increasing tightness of code required buildings, there have been situations where trapped moisture in wall cavities, unable to exit to the exterior of the wall has collected and resulted in rot, mildew, mold, or structural damage and in extreme cases caused health related concerns and significant financial hardship.

The core of the issue though is moisture accumulation.  Moisture does cause damage and needs to be addressed.  99% of modern newly built homes continue to use a fibrous material to thermally insulate them.  This is the core of the problem.  Because fiberglass, Roxol, cellulose or any other fiber based product is permeable to moisture laden air, and because a vapor barrier is only placed on one side of the wall or the other (In Canada, this is on the warm, indoor side of the wall), moisture does enter wall cavities, where it does come into contact with condensing surfaces and can accumulate to cause damage in tightly sealed homes.

While tight homes are energy efficient, they risk becoming health risks, while freely breathing homes have healthy indoor air quality because of the natural air exchanges that take place each day, they are costly to heat and uncomfortable to live in.  What is the answer?

Fibrous insulation IS at the core of the problem and the reason moisture enters wall cavities.  What if the insulation used in homes was impermeable to air & moisture – it would not matter where the vapor pressure was coming from, moisture could not enter the wall cavity.  What if the insulation was also able to perfectly seal the wall cavity so that no air could move around it either?  Such a wall assembly would by design be vastly more resilient to moisture damage and its resultant health concerns.

Spray foam insulation is the solution.  Spray foam insulation has a higher R Value than any other insulation product on the market.  Spray foam insulation is a recognized air barrier and vapor barrier, meaning it is impervious to moisture and prevents the damage water can cause.  Spray foam insulation is custom fit to the walls of your home because as it expands it wraps itself around every element in your walls and seals them entirely.  Unlike fibrous products which will settle or sag over time, spray foam will never move, never deform – it is elastic enough to allow for settling of new homes and moves with the framing members.

With spray foam insulation, the modern mantra “Build it tight, ventilate it right.” results in not only energy efficient homes, but healthy indoor living environments and durable buildings by preventing moisture and its resultant damage from entry.

Tags : air quality, building envelope, Environment, moisture, spray foam insulation
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