The Problem:How do you install 8 to 10 inches of fiberglass insulation in a steel frame 60 inches apart made of zee sections?
The Solution: A unique simple and dollar saving approach to the problem was developed in 1993. Suspender Bar is a simple bar and clip component that spans purlin to purlin from the bottom flange, supporting thick layers of uncompressed fiberglass and vapor retarder above.
The traditional method
Fiberglass insulation works by trapping dead air. When the dead airspace is crushed by squashing the insulation blanket then fiberglass is no longer effective. No trapped air equals no real insulation value. The traditional method to insulate steel buildings is to stretch the fiberglass blanket over the purlin frame before the roofing is installed. The roofing is then applied resulting in severely smashing the fiberglass. This compressed fiberglass cannot trap dead air thus cannot perform its job. The owner is paying for insulation value they are not receiving.
Early attempts at increasing the fiberglass R value are weak in actual performance or have proven expensive. The sag and bag method attempts to add thick fiberglass over the top of the traditional thin blanket. In reality the contractor never allows the thin blanket to sag. The result is just more compressed fiberglass that cannot perform.
The Attempt
The Result
Strap Systems
Other attempts include systems that employ straps installed into grids. These systems are slow in that they require going over the building three times. Once to install the strap, once to install the vapor retarder, once to install the insulation. Only then are you ready to install the roof. Another challenge of these strap systems is they install from the top thus the building is exposed to rain and wind elements slowing the installation progress. Lastly in an attempt to exclude competition these systems require use of proprietary vapor retarders that are costly. Single source always is.
Other Systems
A number of systems are in the market that require rollers, racks and gear on top of the roof frame. Names such as Elaminator and Purlin Glide describe these systems. Such systems tout "Fall Protection" as their feature. In reality it is lots of expensive equipment that must be transported to the site, raised up, and moved around the roof, all in the name of high R value. Traditional fall protection measures are effective and inexpensive. Remember the original goal was only to insulate the building.
Why Suspender Bar is superior
Suspender Bar does only one thing. It holds up thick, uncompressed fiberglass blankets in Zee purlin roofs of steel buildings.
The owner gets the R value he pays for. No special equipment is required to install Suspender Bar. Any quality vapor retarder is fine. There is no proprietary restriction. Fiberglass insulation may be purchased from all the normal sources at competitive prices. Because Suspender Bar installs from the bottom, after the roof is installed, the building is quickly "dried in" saving time saves money.
He means well but he has little experience with steel buildings. His normal attempt is to stuff 24 inch wide insulation batts in the cavity and tie it up with some sort of wire and paper. His fiberglass batts don't fit the cavity correctly, leaving voids (thus allowing heat to escape). The finished appearance leaves lots to be desired.
This local guy tried holding it all up with rebar!
Fiberglass insulation works by trapping dead (non moving) air in its small cells between fibers.
The more air trapped the better the insulating value. Thus a thicker blanket of fiberglass insulation will keep your building cooler (or warmer) than a thinner one. Suspender Bars are a support system that allows for a very thick blanket of insulation to be installed in the roof of a metal building. The building is erected and roof applied. The thick fiberglass blankets are then installed from the inside. Blankets of fiberglass with white facing are unrolled and pushed up into the cavity between the building purlins. Suspender Bars are installed spanning purlin to purlin every 24 inches holding up this thick blanket. The unique spring clip of the Suspender Bar hold the bars snugly to the bottom flange of the steel purlin. Tabs of facing on the edges of the insulation rolls can be overlapped and taped or spray glued together, covering and hiding the steel purlin.
Compressed insulation CHEATS
the owner of the building
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How Suspender Bar compares to other insulation methods
