Tag Archives: Construction and Maintenance

Tools of the Trade Part III

Our previous post focused on the infrared thermal imaging scanner that we use to detect air infiltration into new and existing homes.

Infrared Scanner

Infrared Scanner

In this post we’ll focus on another of the diagnostic tools of the trade that we use to verify supply and return-air efficiencies in forced-air heating/cooling systems.

We use the Minneapolis Duct Blaster to perform a “Total Leakage Test” of the duct system.

Duct Blaster

Duct Blaster

The Duct Blaster is a device that uses pressure testing to find the amount and location of air leakage in a duct system.
To do the test, we seal all outlets except for one on the return side of the system. This is the side that returns stale air to the furnace to be reconditioned. The Duct Blaster is connected to this return-air opening and then turned on to blow air into the ducts. The air goes through the return ducts to the air handler and then through the supply ducts. If the duct system is very tight, it doesn’t take much airflow through the fan to pressurize the ducts. If you have a big leak, like a disconnected plenum or duct, it will be next to impossible to pressurize the ducts adequately.  This would be like trying to pump air into a tire that has a big hole in it.

The process yields quantitative results because testing requires two pressure measurements: one inside the ducts and the other inside the fan. The first allows the tester to compare results from different systems by always pressurizing to the same level. The second measures the airflow in the fan when that level is reached. As mentioned above, tight ducts means low airflow, and leaky ducts require lots of airflow.

Pressurizing only the ducts determines the total leakage. That includes the air that escapes into the conditioned space and the air that leaks to the outside of the building envelope (i.e., the attic or crawl space). The latter is the most important part because you derive no benefit from it. To separate it from the total leakage, we pressurize the house to the same level as the ducts by using the Blower Door. Then, when the Duct Blaster brings the ducts up to the required pressure, none will leak to the inside of the house because it’s at the same pressure as the ducts. The fan only has to blow enough air in to make up for the leakage to the outside, and that’s the amount that’s important.

This is a picture of the blower door ready for use.

This is a picture of the blower door ready for use.

In a tight air distribution system, the leakage to the outside (in cubic feet per minute, or cfm) will be 5% or less of the square footage of the home. Most new installations start at about 15% to 20%, and go downhill from there. At those rates, a third of the heating and cooling bills could be a direct result of duct leakage.

After performing a Duct Blaster test to determine the amount and locations of air and duct leakage, we seal up the leaks that we find. Upon completion the house and/or duct system will perform better, and your heating and cooing bill will be lower.

You can follow this link to a you tube video part 1 of 4 videos.

As they say at Focus on Energy, “Testing Trumps Talk” and we couldn’t agree more.
By testing and  verifying the tightness of the building envelope and the duct systems in our high-performance homes, we are able to identify any deficiencies and take corrective measures.

Lower operating costs, greater comfort, safety, durability and higher resale values are just a few of the benefits realized by implementing building science principles and best practices into the homes that we build.

By testing, inspecting, and documenting the quality of work, we bring a higher level of added value and peace of mind for our clients.

The Duct Blaster is another diagnostic tool of the trade that helps us in delivering the added value that is built-in to our high-performance homes and remodel projects.

If you’d like to learn more about how we can provide added value to your new home or remodel, please visit our website and contact us.

In our next post, we’ll talk about mechanical ventilation, exhaust equipment and the diagnostic tools of the trade that we use to verify performance and efficiency of this critical component of the high-performance homes we build.

Great Lakes Carpentry is “Building Today for a Greener Tomorrow.”


Ice Dam Prevention

The long winter months can be hard on your home.  Snow build up on the roof can get heavy and cause damage either while it’s on the roof or as it’s sliding off. One of the most common problems in the winter are ice dams.

An ice dam is a build up of ice right at the edge of the roof.  Since heat rises, the snow that is on top of the roof melts, as it melts, the water travels to the edge of the roof.  If your home has an overhang, the water will get trapped there and freeze because the roof is not heated in that spot anymore.

A few ways to prevent this from happening include:

1. Making sure all openings to the outside, such as attic hatches and exhaust ducts are tightly sealed. It is also important to make sure all the vents lead outdoors and not to an open space in the attic or between walls.  Spread fiber-reinforced mastic on the joints of HAVC ducts and exhaust ducts.  Covering them entirely with R-5 or R-6 foil faced fiberglass will keep heat from escaping as well.

2.  Add insulation to the attic floor to keep heat where it should be, in your home. This will prevent the heat from inside your living space from escaping through the roof.

3. Caulking penetrations is also important to preventing ice dams. Seal around electrical cables and vent pipes with fire-stop sealant.

4.  Keep your whole roof at the same temperature. If the middle of the roof is warmer than the edges, the snow will melt in the middle which will then travel to the edge of the roof. Since the edge of the roof is colder, the water will freeze again causing an ice dam.

Great Lakes Carpentry understands the importance of of preventing ice dams from becoming an issue in your home. Implementing building science and best practices will prevent snow and ice build up on your roof.

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Stongwood Log Homes: Advantages to kiln-dried logs

Wisconsin Energy Star rated and Green Built Certified Stongwood log home in Tomahawk Wis.

The number one feature that sets Strongwood apart from its competitors is the fact that they properly kiln-dry their logs.  This is the process of removing moisture from the log.  Properly kiln drying logs can remove up to 10 thousand pounds of water out of the typical log home.

Many competitors who kiln dry their logs only do so for about a week or two. Stongwood kiln dries their logs from anywhere between 28 and 52 days, depending on the diameter of the log.  Taking the time to kiln-dry logs offers numerous advantages.

This is an example of butt and pass.

This is an example of saddle notch.

– No log shrinkage
– Miniscule log settling
– Minimize log checking and cracking
– Eradicate mold and bug larva that still may be existent in the log
– Reduce construction costs and trim labor
– Less likelihood of warping, twisting, and shrinking
– Less oozing sap

Kiln drying logs provides you with energy-efficient log walls with airtight joints.

This will allow your home to be more cost-effective at the outset and over time.

Just like any other home, a Strongwood log home is fully customizable.  They

This is the first full log home in the State of Wisconsin. Here you can see the dovetail style of the home.

offer the largest variety of log profiles in the industry.  Some of the styles include full-round, D-logged, rectangular, Swedish coped, butt and pass, and dove tail.

To see more Stongwood homes visit their website.  Also don’t forget about Great Lakes Carpentry, we are more than happy to assist you in building your next Stongwood log home.