by Charles Hendricks | Apr 7, 2014 | architecture, Building Science, Green Building, green term defined, Indoor Air Quality
Permeability is a HUGE topic in our mixed humid climate for anyone involved in the construction industry. The perm rating of a product is the measure of the diffusion of water vapor through a material. This vapor drive through a building material can make or break the durability, efficiency, and indoor air quality of a project.
In our climate, the key is to have a wall and roof assembly that is air tight and vapor permeable. This is an almost impossible task so there are other things that need to be done for the house to be as efficient and durable as possible – but I will not go into that depth with this post.
Vapor permeability (air tight and vapor permeable) is sometimes referred to as the breath-ability of a system or ability to let water vapor pass. This should not be confused with stopping bulk moisture, which is a must for a wall and roof assembly. Bulk water is moisture in liquid form and water vapor is a gas.
So why is vapor permeability so important to the health, efficiency and durability of a building system? Because walls and roofs do get wet. Condensation will occur in some systems. Plumbing leaks do happen on occasion. Most important, we have two seasons here in Virginia and therefore have two different vapor drive directions. So walls and roofs need to be able to dry in both directions. When a wall cannot dry out, it becomes susceptible to moisture damage (rot, mold, insects).
Anything with a perm rating of less than 1 is a semi-vapor barrier. These products should be used sparingly for the thermal envelope in our climate. Anything less than 10 has low permeability and care needs to be taken to dry the assemblies out and not trap vapor inside.
Many products we use traditionally need extra thought due to their permeability:
Open Cell Foam = 15 Perms
Closed Cell Foam = 1 Perms
Concrete = 3.2 Perms
Gypsum wall board = 50 Perms
Plywood Sheathing = 10 Perms
OSB Sheathing = 2 Perms
Oil Paint = 1.6 Perms
15# Felt = 8 Perms
Kraft paper batts = 1 Perms
House wrap = range 5 to 50 Perms
Having an architect that understands building science is a must in our mixed humid climate. A well planned wall and roof assembly will be healthy, durable, and energy-efficient.
by Charles Hendricks | Mar 21, 2014 | architecture, Harrisonburg Architect, Indoor Air Quality
What are the things you need to do in your home before the new baby comes home? What precautions do you need to take? What changes do you make?
Those of us with children have gone through the process – time to baby proof your home. You purchase electric outlet covers, make sure the chemicals are put away in locked cabinets, and install the baby gate. We paint the new nursery and build the crib. So what did you miss? What other things should you do?
There are other things that you should consider. First while installing the outlet covers, be sure to take the outlet plate off first and
caulk the openings around the box. This will improve the
indoor air quality of your home. Air leakage is a huge problem for indoor air quality and we all want the best environment possible for our children.
When painting the nursery be sure to use
No VOC paints so that you are not introducing chemicals into the sleeping environment. VOC’s used to be a standard in our household paints and many other products, but now with a little research you can find better solutions.
Install your CO2 sensors to further protect the indoor air quality. Many houses have smoke detectors, but they should also have CO2 Sensors. While you are at it, do a radon test. We have heard of many homes in our area having high levels of radon after the Earthquake a few years ago.
Other things to consider, easy access into the home for the stroller. If you have the opportunity to build it new,
plan for easy access for those days when your hands are full. Make sure you have
easy to function assemblies around your home, water dispenser in the fridge that
only requires one hand when your other has a baby in it. Door handles should be able to function with your elbow. Make sure you have the
home automation system installed to be able to monitor what is going on to give you more freedom to move around the home.
Bringing a baby home is a wonderful time in your life. Enjoy it worry free by taking these extra precautions.
by Charles Hendricks | Mar 11, 2014 | architecture, Building Science, Harrisonburg Architect, Indoor Air Quality
Comfort issues in your home are often caused by things behind the walls.
Air tight and vapor permeable is a known goal for any home that is built today to a higher standard. We want comfort in our rooms, even temperatures, and lower electric bills. It is important to get the details right during construction to achieve those goals. We spend 90% of our time indoors. Building your home right will improve the indoor air quality, energy efficiency, and durability of your home.
This particular home used fiberglass insulation in the sloped ceiling. This does not allow for the attic space to be air tight, enough room for ventilation, or enough room to properly insulate the space. A leak in the top of the home (joints in the drywall) allows warm moist air to flow through the existing insulation building up moisture. This can lead to rot and greatly diminishes the effective insulation of the material. The eaves allow some air to infiltrate from outside, but not enough to allow the air to dry the sloped ceiling space. All of these issues can be avoided with a sloped ceiling with a good understanding of building science. Whether the space is above a garage, finished attic, or a vaulted space in your living room – proper insulation strategies are critical to reduce comfort issues in your home.
Read about this home addition’s building science issues in our blog post.
by Charles Hendricks | Mar 7, 2014 | architecture, Building Science, Indoor Air Quality, LEED
Going green when building a sustainable home is the first step in ensuring you are helping your environment and your wallet for years to come. How are your eco-friendly decisions benefiting your home?
It is easy to dismiss making a decision that protects forests in South America if you have no direct attachment to South America. Using FSC certified wood is more expensive on a cash basis without a doubt. So why would you ever care about using this strategy? FSC is a third-party certification that protects rain forests in South America from being clear-cut.
How do we put value on saving these forests? It is difficult, however those forests are filtering air, sequestering carbon, and producing oxygen to breathe. So inherently we know the health of those forests is important, but again, is it worth paying more to build your home to protect forests half a world away?
Precious wood at Mil Madeiras Ltd. FSC, from sustainable logging. Amazon, Brazil
Deciding to build a healthy, energy-efficient, and durable home is not as complicated a decision as deciding which strategies are right for your home and budget. These are complex issues that should be considered with the full impact on the future of our world and the impact on your project. Installing a more expensive HVAC system, for instance, that saves you money through energy efficiency can easily be evaluated on a payback basis. Installing insulation that is air tight and vapor permeable is critical to maintaining your monthly finances and can also be easily evaluated. Using healthy products that do not off-gas dangerous chemicals into the air you breath should be done without a second thought.
Going green is not a political decision. It does not cost more if planned through design using the right strategies for your project. Going green benefits your wallet, the planet, and future generations to come.
Crossroads Farm
Wolford Dedication
by Charles Hendricks | Mar 5, 2014 | architecture, Building Science, Green Building, green term defined, Indoor Air Quality
There are many terms used to describe a home that is built to a higher standard, green, sustainable, LEED Certified, and EarthCraft Certified to name a few. EarthCraft is a regional green rating system that has been adopted across the Commonwealth of Virginia.
Projects that receive EarthCraft certification have an independent third-party verification, along with meeting the EarthCraft programs criteria. The EarthCraft brand ensures each project addresses indoor air quality, energy and water efficiency, reduced resource consumption, and reduced maintenance demands.
Developed in 1999 by the Greater Atlanta Home Builders Association and Southface, EarthCraft was adopted in Virginia starting with the Blue Ridge Area Home Builders Association. This is the only regional green building residential rating system in the state. There are certification programs for Single Homes, Light Commercial projects, multi- (more…)
by Charles Hendricks | Feb 28, 2014 | architecture, Building Science, Indoor Air Quality
We spend a lot of time thinking about the health impacts of the building when designing an energy-efficient home. The ventilation rate needs to be designed and the materials used should be selected with care.
Then construction starts and it is cold outside. The next thing you know there is a portable heater sitting in the future living room. These machines are terrible for air quality for those building your project. Fuel oil off-gassing can have serious health impacts. The chemicals from the burn process can be absorbed by wood and drywall in your project and held until the project is finished.
Here is a solution used on a project we designed to be LEED Certified to keep the burn process outside the building envelope while sending the heat to the inside of the building.
From a report done by Michigan State University: Following tests of 18 types of portable, unvented heaters, Consumer Reports states that: “We calculated the concentration of four gases produced by these heaters — carbon monoxide, carbon dioxide, nitrogen dioxide, and sulphur dioxide — in a 10x12x8-foot room with normal ventilation. The levels of each gas were high enough to be a serious health hazard to high-risk groups, including pregnant women, asthmatics, people with cardiovascular disease, children, and the elderly. The levels we calculated for some pollutants may pose risks for healthy people.”
This particular home used fiberglass insulation in the sloped ceiling. This does not allow for the attic space to be air tight, enough room for ventilation, or enough room to properly insulate the space. A leak in the top of the home (joints in the drywall) allows warm moist air to flow through the existing insulation building up moisture. This can lead to rot and greatly diminishes the effective insulation of the material. The eaves allow some air to infiltrate from outside, but not enough to allow the air to dry the sloped ceiling space. All of these issues can be avoided with a sloped ceiling with a good understanding of building science. Whether the space is above a garage, finished attic, or a vaulted space in your living room – proper insulation strategies are critical to reduce comfort issues in your home.
Going green when building a sustainable home is the first step in ensuring you are helping your environment and your wallet for years to come. How are your eco-friendly decisions benefiting your home?
