Fiberglass batt insulation works in two ways to provide thermal insulation. First, air is trapped in the tiny spaces built into each batt, slowing down conductive heat movement. Second, the glass fibers reduce radiant heat loss, adding further insulation value. Important to note is that small air voids (within the fiberglass batts) will slow heat flow, while larger voids will actually do the opposite. These are dynamics that will impact the performance quality of the installation.
For many a homeowner, installing fiberglass insulation might seem like a viable DIY project. In short – it’s not. For the maximum in product performance, a professional install is recommended. Expert installers ensure the best contact between batts and surfaces, as well as a snug fit between batts. Doing otherwise will compromise both air leakage and thermal performance. As well, an expert install will guarantee that an effective moisture barrier will be installed accordingly.
Fiberglass batt insulation must also accommodate irregular cavities, ductwork, plumbing and wiring. Here, the batts must be precisely cut to fit, and placed strategically to allow for optimum performance. This is not a time for installation shortcuts, a hurried job, or a sloppy install – even by an expert. For the best long-term results, it’s important to follow manufacturer specifications, as well as any prescribed building code. Not doing so will present future complications.
Fiberglass batt insulation will insulate properly when air can be effectively trapped. As it is, the batts are not meant to be an “air barrier” themselves, which means that a space like the attic still requires sealing. This is where spray foam insulation may play an integral part in complimenting the performance of the batts. For the professionals, sealing a space tight (whether the attic or the basement) is essential for any insulation product to deliver their advertises outcomes.
To have a building inspector or energy auditor discover flaws and weaknesses in insulation after a job has been done is counter-productive. This is work that should be done right from day one. It means hiring an installation team that understands fiberglass batts; has expertise with the install; and has a quality approach to the overall project. More importantly, it’s essential to do business with a company that is reliable and reputable – price shopping will not always work.
Since every home is going to be different, installers need to fully appreciate the space that’s being insulated – it could be a cathedral ceiling; an area with pre-existing framing; even thermal defects that came with the original construction. Whatever the case (and especially during a renovation), it’s best for trades to work together to ensure the best results. Leaving even the smallest details unattended can have an impact on the integrity of the insulation and on the R-Value.
Where fiberglass batt insulation is recommended or specified, there is no alternative to installing everything properly, and without cutting any corners. Even with possible extra labor costs, there are no disadvantages to doing everything right the first time – and long term results will show.