Tag Archives: 2nd floor

2nd floor ventilation system

I had a plan for the 2nd floor duct installation, and I had my six and eight inch round ducts. But they are not your everyday ducts. They are special for a couple of reasons.

Quality material

First off, they are called GreenSeam or GreenSeam Plus and they have built-in neoprene gaskets in the longitudinal seams. Once you snap and lock the pipe together along the longitudinal seam, the gasket should render it airtight.


The GreenSeam Plus, which is easily identified by the green band around the pipe end, has a gasket that is supposed to seal the travers joint, in addition to the longitudinal gasket. Furthermore, the GreenSeam ducts come in 26 gauge, compared to the thinner 30 gauge ducts you typically find in the big box home improvement stores.

In summary, I have sturdy 26 gauge ducts with gaskets for air sealing at the traverse and longitudinal joints. And the last time I checked, they were only incrementally more expensive than the big box products.

Air tightness

The ventilation system duct work should be airtight for a number of reasons. You want to control where the fresh air is delivered and where stale air is removed from the building. Leaky duct work would deliver or remove air where it is not needed, or where it could even be damaging.

The GreenSeam duct products with their gaskets make it a whole lot easier to air seal your ventilation system. To nip any remaining leaks in the bud, I sealed all seams on the outside with duct mastic. This is particularly important on elbows and tees, which have moving parts and joints without gaskets. And, of course, I sealed around all sheet metal screws I used to hold the duct work together.


The duct mastic also helped with air sealing the transition from a rigid to a flexible duct. The flexible duct was pushed over the rigid duct after it received a good coating of mastic on the duct end. Everything was then tightened up with a big zip tie.


Now that we had the technical aspects and quality control issues addressed, it was time to throw some ducts around!

The installation started at the ERV end for the supply and return lines. From here I could run the ducts to the various supply and return points (see also 2nd floor ventilation layout in preceding post).

We ran all the ducts in the attic above the 2nd floor ceiling joists. We had to lower a couple of ceilings toward the back end of the building (the bathroom and second bedroom) to have sufficient space for the ducts. The attic toward the front was tall enough to fit everything in.

A big thank you to our friends Vincent and Rubani for assisting me with the installation!

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Lessons learned: 1st floor ventilation

We have a special friend. His name is Erv, and he brings us fresh air into the house year round. Other people have the same friend, but they call him ERV, or sometimes by his full name: Energy Recovery Ventilator.

The ERV is a well appreciated equipment. Because our house is almost completely airtight, we need mechanical ventilation to remove the stale air and bring in fresh air. The ERV does just that, assures good indoor air quality, and in the process keeps us comfortable with the enthalpy wheel. It acts as a heat exchanger and removes excess moisture.

I like to put it this way: Using the ERV is like keeping windows open during the winter to get fresh air in, with the exception that it doesn’t get cold. It works so efficiently that it helps us to delay our heating season by up to four weeks.

The fresh air is distributed across our 1st floor apartment through a system of ducts, supplies and returns. I was about to embark on the ductwork installation project for the 2nd floor. But before doing so, I wanted to review our 1st floor ventilation system: What worked, and more importantly, what could we have done better?

Stale rooms (with a lowercase s)

The 1st floor ventilation system has fresh air supplies in key rooms to assure fresh air distribution across the apartment. A series of undercut doors, ‘indoor pressure balancers’ and ‘between room vents’ help move air from room to room and to eventually to the returns in the two bathrooms.

We can easily flush stale air out of the apartment by cranking up the ERV. However, if we run the ERV on the low setting (low airflow), the library and living room remain somewhat stale for longer than any other rooms in the unit.

In other words, the fresh supply air is not mixing sufficiently with the room air. The velocity from the fresh air supply in the foyer is good, but too slow when moving on to the library and living room.

To avoid something similar on the 2nd floor, I plan on adding a fresh air supply to the library and living room.

Noise transmission

The first time we fired up our first floor ventilation system, it sounded like a roaring jet engine. That problem was quickly solved with two three-foot pieces of insulated flex duct connecting the ERV to the rigid ducts. I made sure we had a 90 degree bend in each flex duct, and our ventilation system fell completely silent – almost.

While the noise transmission from the ERV is under control, we still had some transmission from room to room. For example, the fresh air supply of the office and foyer are connected by a six foot duct. The noise transmission through this short duct is as such that two people – one in the office and the other in the foyer – could have a conversation with each other. The longer the duct between supplies, the more faint the noise transmission.

To minimize the room-to-room transmission on the 2nd floor, I plan on using a three foot piece of insulated flex duct with a 90 degree bend right after every supply to act as a sound muffler. This will also increase friction and reduce velocity, but I will try to make up for it through more generous duct sizing.

2nd floor ventilation layout

The plan below shows the 2nd floor ventilation layout with the improvements mentioned above:

  • Using flex duct at each supply as a sound muffler to reduce room-to-room sound transmission
  • Adding fresh air supplies to the library and living room to improve mixing with the room air and a more efficient flushing of the stale air, even at lower airflow rates.

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Putting a frame on the kitchen ceiling

My to-do list for the second floor is long. Two items at the top of that list are the ventilation duct work and the electrical installation. Before I could get to those two items, I had some ceiling framing to finish.

In preparation for the roof insulation, we removed the ceiling joists in the back third of the second floor. This was so we had enough room for the insulation and the ventilation duct work.

My friend Rubani and I had begun to rebuild drop ceilings in the bathroom and guest bed room. It was now time to tackle the framing of the kitchen ceiling.

When we removed the ceiling joists, I put them to the side so that they could be reused for the drop ceiling. These are old growth two by six, meaning they actually measure two inches by six inches, compared to the nominal lumber which measures one and a half inches by five and a half inches.

That matters because I have to use joist hangers. And joist hangers are made for nominal lumber.

I was in no mood to carve the ends of the old growth studs to fit the joist hangers. It turns out that you can find joist hangers for old growth lumber online. Ordering them took a little longer than picking the up at the store, but it saved me time and a headache.


Thanks again to Rubani for helping me to lift the old growth two by six into place!

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Window aluminum cladding

The 2nd floor windows were installed and air sealed, but still needed some protection from the elements. In short, I needed to add some aluminum cladding to prevent bulk water from seeping in around the windows.

I had an interesting experience when I had the aluminum cladding added to our 1st floor replacement windows. I learned that this job requires attention to detail and a specific skill set: Taking accurate measurements.

The contractor I hired for the 1st floor windows was somewhat deficient on both, so I ended up finishing the job myself. With that I felt fairly confident to take on all our 2nd floor windows … except that they are just a little higher off the ground. But that wasn’t a problem. I put up scaffolding so I had a safe working platform 20 feet off the ground.

window-47 window-48 window-49

I bought two coils of sheet aluminum, a bunch of caulk, and rented an aluminum brake (also called siding brake). Because of the elevation I moved slowly but deliberately. I have to admit, it was rather exhausting because of the concentration and focus it took. But after four days of measuring, cutting, bending, trimming, fitting, and caulking, I had all windows cladded. Again, just in time for the winter season. Hurray!

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2nd floor replacement windows

1st floor window cladding – or cluster

1st floor replacement windows

2nd floor replacement windows

My entrance into the world of energy efficient yet affordable windows started with a lot of research, and I mean a LOT of research. I had to acquaint myself with new vocabulary like “triple pane insulated glazing units,” or “solar heat gain coefficient.”

But it was worth it and it paid off. The replacement windows for the basement and 1st floor have served us well. They kept us comfortable on even the coldest days and keep our heating bills low.

I was very happy to tap into my acquired expertise again, this time to get our 2nd floor replacement windows installed. This time around it was a breeze, because our friend Drew and I had already done all the prep on the second floor window bucks a while back.

And on the purchasing side, I went around to check the specifications, performance values, and prices on triple pane insulated glazing units from local manufacturers. And I found what I was looking for – energy efficient windows that did not break the bank.

How did I know that I was looking at high performance windows? The National Fenestration Rating Council (NFRC) developed a national rating system for windows so that a consumer can compare apples to apples.

window-45 window-46

  • U-factor: 0.17
  • Solar heat gain coefficient (SHGC): 0.20
  • Visible transmittance (VT): 0.35
  • Air leakage (AL): ? 0.3 cfm/sf
Fixed casement
  • U-factor: 0.16
  • Solar heat gain coefficient (SHGC): 0.24
  • Visible transmittance (VT): 0.42
  • Air leakage (AL): ? 0.3 cfm/sf

I have written a lot about what these performance values mean, and rather than repeating myself let me link you to one blog post that summarizes the tech talk, or you can click on any of the other links in this blog post.

One thing that I will repeat – because it can’t be said often enough – is the importance of the air leakage metric. Why? Because any insulation is only as good as it is airtight. Take, for example, a ski jacket on a downhill slope. You left the front zipper partially open. Will the jacket keep you warm? No, because the cold air gets in. Same with windows.

The Efficient Window Collaborative recommends windows with an AL of 0.3 cfm/sf or less. A value of 0.3 cfm/sf is like a ski jacket with the zipper partially open. You really want to zip it up. Our target was a value of 0.05 cfm/sf or less.

Our NFRC label says less than or equal to 0.3 cfm/sf. However, to be certain about the actual performance, I asked the manufacturer for the test reports and found that they listed the actual air infiltration at 0.02 cfm/sf. Bingo!

Please note that most labels do not list the actual air leakage value. You will have to ask the vendor for the test data. It is probably the best question you will ask.

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I am just happy that we got the old double hung windows out and the replacement windows in before the winter hit. It will cut down on the heat loss, and changes the look from an abandoned apartment to something resembling a home.

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