Greetings Jerry, I believe I remember reading some Trus Joist technical documentation which indicated no more than one hole should be drilled or lag screw/bolt driven into any cross sectional area of the top flange. If using the Quick Mount Q-Base with two lag screws/bolts, will you be orienting the Q-Base so that the two lags are in line vertically with each other or side by side?... Seems like side by side (straddling the web) may not be a good approach. Staggered vertically (straddling the web) may be alright if the size of the holes and lags are appropriate for the top flange dimensions and can be installed where allowed by the rafter/joist manufacturer's specifications.
I hope you are able to accurately identify the rafter/joist manufacturer and the rafter/joist model so you can reach out to them for guidance on what are and are not acceptable attachment methods for their product. Other thoughts: If access to the underside of the roof structure allows, installing appropriate blocking with proper hangers and fasteners would likely be a more robust way to go. I have looked into using stainless steel j-bolts to hook the underside of the rafter members in situations like this as well; the rest of the install from the top side is just like working with hanger bolts. If the roof decking/sheathing and its attachment fasteners and schedule are all known and sufficient, a multi-fastener deck mount type mounting product may possibly be an appropriate and labor/time saving option. Best regards, ----MATT Matthew Sirum P.O. Box 1227 Greenfield, MA 01302-1227 USA phone: +1.413.773.0611 email: matthewsi...@gmail.com ---------- Original Message Below ---------- [RE-wrenches] TJI rafters Jerry Caldwell solarcowboy at yahoo.com Tue Mar 6 15:57:04 PST 2018 Bill, Mineral bitumen roll roofing. 2:12 slope. Everyone who gave input below, thanks for the suggestions. I've decided to go with the Quick Mount Q-Base product. It allows you to get 2 lag bolts into the top chord on either side of the OSB web. Cheers,Jerry Caldwell _______________________________________________ List sponsored by Redwood Alliance List Address: REfirstname.lastname@example.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://email@example.com/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org