This week, David Bettridge will catch us up on the downstairs progress. Drumroll, please…
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When we moved in to this house, we noticed right away that sound travelled pretty well between the upstairs and downstairs. One of our goals is to fix that during the downstairs renovation. If you remember your physics, you know that sound travels as vibration. Usually we think of it as traveling through air but it can also be transmitted through other materials.
Working with Acoustical Supplies in Providence, we came up with a three-pronged attack on noise:
1. Insulation to absorb air-borne sound
2. Sealing to keep airborne sound from leaking through
3. Mass (weight) and mechanical separation to slow sound vibrating through the structure
UltraTouch Demin Insulation batts have the same R-19 insulating rating as fiberglass but have a higher STC (sound transmission control) rating…
Being made of 80% post-consumer cotton, they also have several planet-friendly benefits — they don’t cause itching like fiberglass insulation, they don’t outgas formaldehyde or any other nasties and they qualify for LEED points. Plus it’s denim. How sexy American is that?
Once cut to the proper size the batts are pressed into place and fluffed so they aren’t too tight or too loose. Special wires are sprung into place to hold the batts so they don’t slip out of place…
UltraTouch is slightly heavier than fiberglass. But the main difference between the two is the prodigious amount of dust generated when handling the cotton and the difficulty in cutting it. Fiberglass is easy to cut with a utility knife, even while installed in a stud or rafter bay. The UltraTouch requires fairly careful measuring because it doesn’t compress nearly as much as fiberglass. Actually, this is a good thing because over-compressed insulation doesn’t work as well.
Bonded Logic, UltraTouch’s manufacturer, recommends several specialty tools for cutting it, but I didn’t plan ahead so was left trying their recommendation of a reversed fine-toothed blade in a circular saw. My grandfather’s old worm-drive trim saw fitted with a backwards plexiglass cutting blade works perfectly…
As the ceiling installation progresses, I’ll show two more methods we’ll use to control sound. In the meantime, my wife wants to know if this double-denim ceiling makes her butt look big?
