Moisture Control in Homes:<\/strong><\/h1>\nWhat is the most basic protection that a home provides you?<\/p>\n
Shelter. We need shelter to keep bugs, critters, and beasts at bay. We also need shelter to protect us from the burning noonday sun, as well as from the cold winter winds.\u00a0 All of these things are easy enough to keep out; all you have to do is build a cube, with 4 walls, a ceiling, and a floor.\u00a0 Maybe throw in a door so that you can come and go as you please, and perhaps a few windows for natural light!<\/p>\n
Simple enough, build a cube and you have a home!\u00a0 But wait, there\u2019s still one threat we haven\u2019t accounted for.\u00a0 Something we can\u2019t live without, but we\u2019re often trying to avoid contact with.\u00a0 Water!<\/p>\n
Water seems like a harmless enough threat, until you get caught outside in a severe rainstorm, or even worse, if you fall out of your boat into the lake!\u00a0 In these situations, water can be pretty threatening.\u00a0 But the threat doesn\u2019t end if we simply stay in our boat or put a roof over our heads.\u00a0 We have to keep the water from permeating our cube\u00a0entirely<\/em>, otherwise it can be destructive in some brand new and sinister ways. This is why moisture control is very important.<\/p>\nMoisture in building materials leads to rot, which can compromise the structural integrity of the home.\u00a0 Moisture on organic materials that doesn\u2019t dry out quickly can lead to mold, which can compromise the structural integrity of our lungs and impact our health.\u00a0 \u00a0There are countless other problems that moisture can cause, such as ruining your treasured possessions, watering down your beer, or simply dampening your spirits.\u00a0 Seriously, this is why building science has been combating water as one of its key adversaries since the advent of the mud hut!<\/p>\n
Moisture control does not seem like a difficult concept in theory….but, water can flow in multiple and unexpected ways.\u00a0 In building science, there are 4 key ways<\/strong> that water can flow through a home.<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>1. Bulk Water<\/strong><\/h1>\nThe first way is through bulk water entry, such as rain or snow, or flooding from ground water.<\/p>\n
A pitched roof over the home does most of the job, and if we put an impermeable roofing material on top, with each shingle overlapping the shingle below, all the way to the peak, we have a “watershed” moment!<\/p>\n
But hold on! Now all that water is running off the roof, and is cascading down onto the ground right next to the house.\u00a0 This is making a muddy mess, and we\u2019re in danger of flooding.\u00a0 This may also be causing damage and settling to the very foundation which our cube sits atop! However, do not fret; we have some moisture control solutions:<\/p>\n
Gutters – to collect the roof runoff!<\/p>\n
Downspouts – to drain that water down to the ground!<\/p>\n
Downspout Extensions – to kick that moisture away from the house and into the yard!<\/p>\n
Grading and drainage – to slope the dirt around the home to make sure that water runs away from the foundation!<\/p>\n
Sump pumps – If moisture still comes in contact with our foundation, we can prevent our basement or crawlspace from flooding by installing a buried perimeter drain system, to collect that water, direct it to a sump pit, and install a sump pump to discharge the water!<\/p>\n
This all works great. Is it a fool-proof way to keep the bulk-water out?\u00a0 At least for our simple cube.\u00a0 However, the problem is, nobody really wants to live in a cube these days.\u00a0 We want unique homes that are aesthetically pleasing, with several different angles, shapes, and changes in materials.\u00a0 This complicates things immensely.\u00a0 Now we have to apply our \u201cone shingle over the other\u201d theory to all of these oddly shaped areas.<\/p>\n
We need to install flashings! What are they? Flashings come in various shapes and sizes, depending on the application, but typically they are comprised of sheet metal which has been shaped for a particular application, and installed to direct the flow of water away at a transition of materials or change of direction in the structure. Roofs meet sidewalls, and need flashing under the siding but over the roof.\u00a0 Kick-out flashing is needed at those tricky roof to sidewall to gutter junctions.\u00a0 Flashing is needed where siding rests atop brick or concrete, and flashing details are required over windows, doors, and over deck connections to the house.<\/p>\n
Building code has developed requirements and best practices for moisture management, but unfortunately not all homes were built to today\u2019s code standards, and even on new homes these details are easy to overlook. Add to this the possibility of poor workmanship, and the fact that many weekend warriors tackle projects that are out of their league, and you can imagine there are numerous ways for our “watershed” moment to end in failure.<\/p>\n<\/div>
<\/div><\/div><\/div>![](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Bulk-Water-example-2.jpg\" "\\"Bulk")
<\/span><\/div><\/div><\/div><\/div><\/div><\/div>2. Capillary action<\/strong><\/h1>\nSo we\u2019ve solved the bulk water issue, haven\u2019t we?\u00a0 Water runs downhill, and we\u2019ve overlapped everything on our home to make sure it runs off of the building instead of into it.\u00a0 But wait!\u00a0 Water can change direction on us.\u00a0 It can run uphill, through a principle called capillary action. This concept is demonstrated if you dip a paper towel into a spill on your counter top.\u00a0 As soon as it makes contact with the liquid, the paper towel sucks that moisture upwards<\/em>.<\/p>\nNow imagine your siding is somewhat porous.\u00a0 Not as porous as a paper towel, one would hope, but all wood and masonry materials are permeable to a degree. So we keep these materials away from contact with potential standing water to aid in moisture control.\u00a0 We keep the siding or brick off the ground, leaving a 6-8\u201d gap between the siding and the soil where the foundation is exposed, to prevent water from soaking up into the wall. We install building paper or house wrap behind these siding materials, to provide a drainage plane in case moisture does penetrate.<\/p>\n
At roof edges, we install drip edge flashing under the shingles. This provides a simple capillary break, so that the water can drip off of the bottom of the metal flashing material rather than wicking up under the shingles and causing potential damage to the roof decking and eaves.<\/p>\n<\/div>
<\/div><\/div><\/div>![\"Air](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Capillary-action-diagram.jpg\" "\\"Capillary")
<\/span><\/div><\/div><\/div><\/div>![\"Capillary](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Capillary-action-example.jpg\" "\\"Capillary")
<\/span><\/div><\/div><\/div><\/div><\/div><\/div>3. Air-Transported Moisture <\/strong><\/h1>\nSo the first two flow paths were easy enough to understand, but this is where we start wading into deeper water, figuratively speaking, of course.<\/p>\n
Moisture is present in the very air we breathe! And our houses are “breathing” this air too, in a sense. \u00a0Inevitable gaps or holes in the building envelope allow air to both enter and escape. With the stack effect, heated air rises through our home, and escapes out the top. \u00a0If air is leaving, it\u2019s also entering, and that\u2019s usually occurring near the bottom plane of the home.\u00a0 In that air, depending on humidity level, gallons upon gallons of moisture can be hitching a ride through our house daily.\u00a0 If that air travels across a surface where the temperature is below the dew point, condensation occurs.\u00a0 Now those gallons of moisture can be beading up on our building materials.\u00a0 And rot and mold come into play again.<\/p>\n
Older homes were built in a manner that allowed them to breathe more easily, with very little insulation to cause resistance, and numerable open paths for air to travel, so that wetted building materials could easily dry out, preventing air-transported moisture from causing damage.\u00a0 The problem is, these old mouth breather houses also exhale a lot of the air that we pay good money to heat or cool. And, energy costs today are far higher than they were back in the old days.<\/p>\n
In the modern era, we\u2019re building much tighter homes.\u00a0 We\u2019re sealing gaps and holes with caulking or spray foam.\u00a0 We\u2019re putting in tightly sealed windows and doors.\u00a0 We\u2019re installing sealed air barriers at the walls, and filling the wall cavities completely with densely packed or air- impermeable insulation such as closed cell foam.\u00a0 The result of these efforts is fewer paths for air to enter or escape.\u00a0 Basically, our cube now looks like a thermos.\u00a0 So we\u2019re retaining much more of that conditioned air. \u00a0And we can prove this with blower door testing. Where it was not uncommon for older homes to lose more than 100%<\/strong> of their conditioned air in the space of an hour, many new homes only lose 10-15% in an hour. \u00a0How’s that for progress!<\/p>\nBut we have to be very careful now not to allow moisture to travel into these assemblies, or it can take a very long time to dry out.\u00a0 We have also now created the potential that humidity cannot easily escape, and the air can become stale and stagnant, so we install mechanical ventilation systems to allow the home to breathe again, but this time in a controlled and more efficient way.\u00a0 One example is the HRV (Heat Recovery Ventilator), which uses a power fan to simultaneously pull incoming fresh air and outgoing exhaust air through a heat exchanger, to help limit energy loss.<\/p>\n<\/div>
<\/div><\/div><\/div>![\"Air](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Air-Exchange-diagram.jpg\" "\\"Air-Exchange-diagram\\"")
<\/span><\/div><\/div><\/div><\/div>![\"Air](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Air-transported-moisture-example.jpg\" "\\"Air")
<\/span><\/div><\/div><\/div><\/div><\/div><\/div>4. Vapor Diffusion<\/strong><\/h1>\nThe moisture is not only traveling in the air that flows through larger gaps, but it can also move through building materials in the form of water vapor.\u00a0 Moisture in the soil under the home can evaporate, and those vapors can travel through the permeable building materials.\u00a0 This is why we install low permeability vapor barriers for moisture control, such as the plastic you sometimes see on the ground in crawlspaces, to prevent the vapors from the soil from permeating the floor and other areas of the home.<\/p>\n
So as you can see, we\u2019re fighting a battle on at least 4 major fronts, just to stay dry.\u00a0 To compound the confusion, the methods that we use to combat these various and bold paths of moisture will vary from climate to climate.\u00a0 In hot, humid climates, the general path of vapor travel is from the outside to the inside, so the vapor retarders are installed on the outside of the walls, behind the siding.\u00a0 In colder climates, the path that vapor travels is generally from inside to out, so instead the vapor retarder is installed on the inside of the wall, behind the drywall.\u00a0 And in climates like Colorado, where we actually get to experience 4 distinct seasons, we\u2019ve argued back and forth for decades on where and how to install the vapor retarder, or we\u2019ve eschewed it altogether, lest in solving a winter problem we cause a summer problem.\u00a0 Today, modern house-wrap materials such as Tyvek are designed so that they can perform as both an air and moisture barrier, while still allowing water vapors from inside to pass through to the outside.<\/p>\n
In humid climates, air conditioning and de-humidifiers can be absolutely essential to moisture control, not just for comfort, but to remove moisture from the indoor air. Conversely, in our dry Colorado climate, a device called an evaporative cooler or \u201cswamp cooler\u201d may be installed in lieu of air conditioning.\u00a0 These systems pump water into pads which surround a large fan.\u00a0 The fan pulls outside air through the wetted pads and then into the house, and as the water evaporates, the air is cooled.\u00a0 And then, get this, in the dry winter months, we might use a whole house humidifier on our duct system to add humidity to the heated air and increase comfort.\u00a0 Both of these devices could be a recipe for disaster in many humid climates, but you can get away with almost anything in the desert.<\/p>\n<\/div>
<\/div><\/div><\/div>![\"Vapor](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Vapor-diffusion-good-example.jpg\" "\\"Vapor")
<\/span><\/div>Good example of vapor sealing.<\/p>\n<\/div>
<\/div><\/div><\/div>![\"Vapor](\"https:\/\/scotthomeinspection.com\/wp-content\/uploads\/2018\/10\/Vapor-diffusion-bad-example.jpg\" "\\"Vapor")
<\/span><\/div>Bad example of vapor sealing.<\/p>\n<\/div>
<\/div><\/div><\/div><\/div><\/div>With all of these “watershed” moments and innovations in building science, we\u2019ve helped push back the tides. However, moisture will undoubtedly continue to fight back, against homes both old and new.\u00a0 A certified Home Inspector can help identify these potential issues, recommend solutions, and potentially help you to avoid investing in a home that is losing this war with water. \u00a0A home inspector is trained to identify those failing components or improper installations which can lead to hidden moisture damage, so you can fix any issues with a home’s moisture control.<\/p>\n
If you believe you have a moisture issue in your home, you may benefit from a mold and moisture inspection or a mold air sample test<\/a>. Give us a call today!<\/p>\n
Moisture in building materials leads to rot, which can compromise the structural integrity of the home.\u00a0 Moisture on organic materials that doesn\u2019t dry out quickly can lead to mold, which can compromise the structural integrity of our lungs and impact our health.\u00a0 \u00a0There are countless other problems that moisture can cause, such as ruining your treasured possessions, watering down your beer, or simply dampening your spirits.\u00a0 Seriously, this is why building science has been combating water as one of its key adversaries since the advent of the mud hut!<\/p>\n
Moisture control does not seem like a difficult concept in theory….but, water can flow in multiple and unexpected ways.\u00a0 In building science, there are 4 key ways<\/strong> that water can flow through a home.<\/p>\n<\/div> The first way is through bulk water entry, such as rain or snow, or flooding from ground water.<\/p>\n A pitched roof over the home does most of the job, and if we put an impermeable roofing material on top, with each shingle overlapping the shingle below, all the way to the peak, we have a “watershed” moment!<\/p>\n But hold on! Now all that water is running off the roof, and is cascading down onto the ground right next to the house.\u00a0 This is making a muddy mess, and we\u2019re in danger of flooding.\u00a0 This may also be causing damage and settling to the very foundation which our cube sits atop! However, do not fret; we have some moisture control solutions:<\/p>\n Gutters – to collect the roof runoff!<\/p>\n Downspouts – to drain that water down to the ground!<\/p>\n Downspout Extensions – to kick that moisture away from the house and into the yard!<\/p>\n Grading and drainage – to slope the dirt around the home to make sure that water runs away from the foundation!<\/p>\n Sump pumps – If moisture still comes in contact with our foundation, we can prevent our basement or crawlspace from flooding by installing a buried perimeter drain system, to collect that water, direct it to a sump pit, and install a sump pump to discharge the water!<\/p>\n This all works great. Is it a fool-proof way to keep the bulk-water out?\u00a0 At least for our simple cube.\u00a0 However, the problem is, nobody really wants to live in a cube these days.\u00a0 We want unique homes that are aesthetically pleasing, with several different angles, shapes, and changes in materials.\u00a0 This complicates things immensely.\u00a0 Now we have to apply our \u201cone shingle over the other\u201d theory to all of these oddly shaped areas.<\/p>\n We need to install flashings! What are they? Flashings come in various shapes and sizes, depending on the application, but typically they are comprised of sheet metal which has been shaped for a particular application, and installed to direct the flow of water away at a transition of materials or change of direction in the structure. Roofs meet sidewalls, and need flashing under the siding but over the roof.\u00a0 Kick-out flashing is needed at those tricky roof to sidewall to gutter junctions.\u00a0 Flashing is needed where siding rests atop brick or concrete, and flashing details are required over windows, doors, and over deck connections to the house.<\/p>\n Building code has developed requirements and best practices for moisture management, but unfortunately not all homes were built to today\u2019s code standards, and even on new homes these details are easy to overlook. Add to this the possibility of poor workmanship, and the fact that many weekend warriors tackle projects that are out of their league, and you can imagine there are numerous ways for our “watershed” moment to end in failure.<\/p>\n<\/div> So we\u2019ve solved the bulk water issue, haven\u2019t we?\u00a0 Water runs downhill, and we\u2019ve overlapped everything on our home to make sure it runs off of the building instead of into it.\u00a0 But wait!\u00a0 Water can change direction on us.\u00a0 It can run uphill, through a principle called capillary action. This concept is demonstrated if you dip a paper towel into a spill on your counter top.\u00a0 As soon as it makes contact with the liquid, the paper towel sucks that moisture upwards<\/em>.<\/p>\n Now imagine your siding is somewhat porous.\u00a0 Not as porous as a paper towel, one would hope, but all wood and masonry materials are permeable to a degree. So we keep these materials away from contact with potential standing water to aid in moisture control.\u00a0 We keep the siding or brick off the ground, leaving a 6-8\u201d gap between the siding and the soil where the foundation is exposed, to prevent water from soaking up into the wall. We install building paper or house wrap behind these siding materials, to provide a drainage plane in case moisture does penetrate.<\/p>\n At roof edges, we install drip edge flashing under the shingles. This provides a simple capillary break, so that the water can drip off of the bottom of the metal flashing material rather than wicking up under the shingles and causing potential damage to the roof decking and eaves.<\/p>\n<\/div> So the first two flow paths were easy enough to understand, but this is where we start wading into deeper water, figuratively speaking, of course.<\/p>\n Moisture is present in the very air we breathe! And our houses are “breathing” this air too, in a sense. \u00a0Inevitable gaps or holes in the building envelope allow air to both enter and escape. With the stack effect, heated air rises through our home, and escapes out the top. \u00a0If air is leaving, it\u2019s also entering, and that\u2019s usually occurring near the bottom plane of the home.\u00a0 In that air, depending on humidity level, gallons upon gallons of moisture can be hitching a ride through our house daily.\u00a0 If that air travels across a surface where the temperature is below the dew point, condensation occurs.\u00a0 Now those gallons of moisture can be beading up on our building materials.\u00a0 And rot and mold come into play again.<\/p>\n Older homes were built in a manner that allowed them to breathe more easily, with very little insulation to cause resistance, and numerable open paths for air to travel, so that wetted building materials could easily dry out, preventing air-transported moisture from causing damage.\u00a0 The problem is, these old mouth breather houses also exhale a lot of the air that we pay good money to heat or cool. And, energy costs today are far higher than they were back in the old days.<\/p>\n In the modern era, we\u2019re building much tighter homes.\u00a0 We\u2019re sealing gaps and holes with caulking or spray foam.\u00a0 We\u2019re putting in tightly sealed windows and doors.\u00a0 We\u2019re installing sealed air barriers at the walls, and filling the wall cavities completely with densely packed or air- impermeable insulation such as closed cell foam.\u00a0 The result of these efforts is fewer paths for air to enter or escape.\u00a0 Basically, our cube now looks like a thermos.\u00a0 So we\u2019re retaining much more of that conditioned air. \u00a0And we can prove this with blower door testing. Where it was not uncommon for older homes to lose more than 100%<\/strong> of their conditioned air in the space of an hour, many new homes only lose 10-15% in an hour. \u00a0How’s that for progress!<\/p>\n But we have to be very careful now not to allow moisture to travel into these assemblies, or it can take a very long time to dry out.\u00a0 We have also now created the potential that humidity cannot easily escape, and the air can become stale and stagnant, so we install mechanical ventilation systems to allow the home to breathe again, but this time in a controlled and more efficient way.\u00a0 One example is the HRV (Heat Recovery Ventilator), which uses a power fan to simultaneously pull incoming fresh air and outgoing exhaust air through a heat exchanger, to help limit energy loss.<\/p>\n<\/div> The moisture is not only traveling in the air that flows through larger gaps, but it can also move through building materials in the form of water vapor.\u00a0 Moisture in the soil under the home can evaporate, and those vapors can travel through the permeable building materials.\u00a0 This is why we install low permeability vapor barriers for moisture control, such as the plastic you sometimes see on the ground in crawlspaces, to prevent the vapors from the soil from permeating the floor and other areas of the home.<\/p>\n So as you can see, we\u2019re fighting a battle on at least 4 major fronts, just to stay dry.\u00a0 To compound the confusion, the methods that we use to combat these various and bold paths of moisture will vary from climate to climate.\u00a0 In hot, humid climates, the general path of vapor travel is from the outside to the inside, so the vapor retarders are installed on the outside of the walls, behind the siding.\u00a0 In colder climates, the path that vapor travels is generally from inside to out, so instead the vapor retarder is installed on the inside of the wall, behind the drywall.\u00a0 And in climates like Colorado, where we actually get to experience 4 distinct seasons, we\u2019ve argued back and forth for decades on where and how to install the vapor retarder, or we\u2019ve eschewed it altogether, lest in solving a winter problem we cause a summer problem.\u00a0 Today, modern house-wrap materials such as Tyvek are designed so that they can perform as both an air and moisture barrier, while still allowing water vapors from inside to pass through to the outside.<\/p>\n In humid climates, air conditioning and de-humidifiers can be absolutely essential to moisture control, not just for comfort, but to remove moisture from the indoor air. Conversely, in our dry Colorado climate, a device called an evaporative cooler or \u201cswamp cooler\u201d may be installed in lieu of air conditioning.\u00a0 These systems pump water into pads which surround a large fan.\u00a0 The fan pulls outside air through the wetted pads and then into the house, and as the water evaporates, the air is cooled.\u00a0 And then, get this, in the dry winter months, we might use a whole house humidifier on our duct system to add humidity to the heated air and increase comfort.\u00a0 Both of these devices could be a recipe for disaster in many humid climates, but you can get away with almost anything in the desert.<\/p>\n<\/div> Good example of vapor sealing.<\/p>\n<\/div> Bad example of vapor sealing.<\/p>\n<\/div> With all of these “watershed” moments and innovations in building science, we\u2019ve helped push back the tides. However, moisture will undoubtedly continue to fight back, against homes both old and new.\u00a0 A certified Home Inspector can help identify these potential issues, recommend solutions, and potentially help you to avoid investing in a home that is losing this war with water. \u00a0A home inspector is trained to identify those failing components or improper installations which can lead to hidden moisture damage, so you can fix any issues with a home’s moisture control.<\/p>\n If you believe you have a moisture issue in your home, you may benefit from a mold and moisture inspection or a mold air sample test<\/a>. Give us a call today!<\/p>\n1. Bulk Water<\/strong><\/h1>\n
<\/span><\/div>2. Capillary action<\/strong><\/h1>\n
<\/span><\/div><\/span><\/div>3. Air-Transported Moisture <\/strong><\/h1>\n
<\/span><\/div><\/span><\/div>4. Vapor Diffusion<\/strong><\/h1>\n
<\/span><\/div><\/span><\/div>