Posts Tagged ‘fiberglass insulation’

Attic air-sealing example: a wide open chase

August 12, 2009
This bathroom framing chase is a trouble spot

This bathroom framing chase is a trouble spot

Here’s an example of an all too frequent attic air-sealing defect.  Very often dropped soffits and chases are left open to the attic, providing big connections between the attic, the basement, the framing, and the outside.  A leaky envelope means you’re wasting energy, wasting money, allowing dust and perhaps critters to enter your home, and often creating comfort problems.

In this case, a partition was built out to create the third side of a tub/shower enclosure.  It does work to make the tub fit perfertly between the enclosure wall.   However, when the original carpenter did

As seen in the attic after moving the insulation away, this chase is big enough to stick an arm or a leg into
As seen in the attic after moving the insulation away, this chase is big enough to stick an arm or a leg into
this, he left a big connection to the attic open as you can see in the photo—show the troubled spot after we pulled back the dirty fiberglass  batt.  Again, this is a very common problem.

We fix this by crawling through the attic and sealing the hole with rigid or semi-rigid material.  Here we’ve used foam fan board since the hole was only several inches across.  Larger holes might new something stronger like plywood.  After sealing, the material needs to be strong enough to support the 10-12” of cellulose that we’ll add to the attic.

The hole is sealed with rigid foam and expanding foam.  After sealing other attic leaks, this with be covered with insulation. The hole is sealed with rigid foam and expanding foam. After sealing other attic leaks, this with be covered with insulation.

There are great ways to avoid this when building a new home.  And we can certainly fix the problem in existing homes.  It is important, though, to rid yourself of these issues to ensure you home is comfortable, safe, and efficient.

Thanks,
Mike

Recessed Lighting & Air-Sealing

August 6, 2009

Here’s a classic example of air-leakage around a recessed light fixture.    The dirty insulation in this photo is from air leaking out of the house and being filtered by the fibergalss insulation before it exits the house.  Dirty insulation around recessed can light(Fiberglass makes an effective filter in this case!)   In fact, insulation that’s dirty on the bottom is one of the clues we look for during a home energy audit.   Leaks like this represents a lot of heat loss in the winter, and depending on wind or duct leakage it can also mean higher cooling bills in the summer.  Fortunately, there are ways to effectively air-sealing around these fixtures.   Add to my to-do list:  we’ll put together a short video showing the problem and the fix.

You definitely want to address this before you add insulation!  Even taking advantage of the insulation tax credit only makes sense if you make sure you air-seal first.  

[Be sure to check out the video on recessed lighting which includes a discussion of airsealing.]

Thanks,
Mike


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