What is the difference between the fasteners and which one is right for me?
The Prest-on family of fasteners can be used for a wide variety of projects. The Corner-Back can eliminate a stud at almost every corner during home building construction, by building a two stud corner. The Corner-Back is also used to secure the top plate (ceiling) to the stud, to reduce truss uplift. The Corner-Back is applied to the drywall first. Framer-Back can also perform the same duties as the Corner-Back, but is applied to the studs before the drywall is installed. The Insta-Back is used to back-block wallboard four-foot edge to four-foot edge. The Insta-Back provides a solid joint between wallboard, no need to cut back to the stud or measure and cut scrap lumber.
What causes roof truss to uplift?
The best available evidence indicates that roof truss uplift is caused by lengthening of the truss chord as its moisture content increases in the winter. Cold winter air, whether outside or inside an attic, can hold very little moisture, so it is almost always close to saturation; that is, it has a high relative humidity. This causes the moisture content of the truss top cord, which is surrounded by that air, to increase. This in turn makes it try to get longer. The bottom cord, which these days is completely covered by insulation, is in a much warmer and dryer environment and therefore tends to stay the same length. In order for the top cord to get longer without breaking the connections to the web members the truss as a whole must arch upward.
Why doesn't roof truss uplift happen with every truss?
The shrinking or swelling of normal wood along the grain, due to changes in moisture content, is very small so that even when the above phenomenon occurs it is not noticeable. However some abnormal types of wood shrink and swell much more along the grain. These include “compression wood”, “juvenile wood”, and wood with high slope of grain. If the lumber used in the top chords of a truss is any of these abnormal types, the truss will tend to arch to a greater extent.
Can truss uplift be prevented?
There appears to be no practical way to prevent truss uplift. At current and likely future energy prices it would not make economic sense to reduce the insulation in order to expose the bottom chord. Nor would it be reasonable to expect the workmen in a truss plant to be able to cull out the abnormal lumber – even the experts have trouble telling the difference. Attempting to tie the trusses down so they can’t arch cannot be recommended. The forces involved are very high and the trusses might lift the entire partition so that the problem appears at the bottom rather than the top. They might even pull the top plate off the partition. Nor does the type of truss make much difference. Howe and Fink trusses tend to arch about the same amount. However, the Fink truss has a more flexible bottom chord which may tend to bend and thus lift the ceiling less.
Are these products up to code?
The Prest-on Corner-back, Framer-back and Insta-back drywall supporting clips are the only clips that are code compliant with the International Building Code (IBC). Click here for our reports.
What are these fasteners made of?
The Prest-on Corner-back, Framer-back and Insta-back are manufactured from No. 24 gauge cold-formed steel.
Where are these fasteners made?
Since 1975, Prest-on fasteners are made in Hot Springs, Arkansas - USA!
When will my order ship?
Orders placed by 7am CT will ship the same business day, M-F. Orders placed after 7am CT will ship the following business day. If you need it by a certain time, please call us at 800-323-1813
How much is shipping?
As our thank you to you for using Prest-on fasteners, we offer FREE ground shipping on every order!