Lag bolts vs GRK RSS screws

[dpr64]

Moved to a new home and will be installing overhead storage racks that I brought with me from the old home... These came with 5/16 3" lag bolts and possibly grade 8. (that is what it states on the manufacturers website as to what is in the hardware bag).
Cannot find where I put them and noticed these self tapping GRK 5/16 x 3 1/8 RSS screws at home depot.
Do they have the same strength/shear/etc. as lag bolts? They have the washer style head and look pretty easy to work with...

 

[Shiftless]

I’m no metallurgist, but I would use those without hesitation. I assume you will locate the wall studs and ceiling framing to sink those long screws into.

 

[1MtnGoat]

I have used GRK RSS on countless projects and never had a problem. I keep numerous sizes in stock at the shop.

 

[loganb]

Sink them into studs and you'll be just fine. Biggest advantage is self drilling and no washer required..plus the same driver for multiple sizes.

If this was an engineered application requiring larger lags they may not be suitable ad pull out strength isn't as high as lags over 1/2" diameter but for this they should be just fine

 

[tarmy]

They both have their place…and galv. Vs non galv. I have started using them for decks and certain projects depending on what I am doing. Love them…

here is an example of both…just built a deck…all GRK…except the fasteners for the ledger board which got lags and thru bolts because of what they were doing. GRK make smaller head screws that I used for certain attachments like thru the Simpson hangers here. Simpson structural screws for the hanger, GRK thru the hangers to tie the hanger, board and ledger together. Good luck OP.

 

[PoorUB]

The will work fine.
Keep in mind one screw, as long as it is in good wood, will probably hold 750 pounds, or more. Then consider what you are putting in the rack. One screw would probably hold up the whole works!

Most of the time the short fall here is not the harware, it is what the hardware is fastened too. The screw will pull out of the wood before it fails.

 

[dpr64]

It is one of these Saferacks from Costco...

 

[manwithtools]

I can assure you that the lag screws supplied with that racking are not Grade 8. The GRK screws will work perfectly for that racking. It's exactly what I used for mine. I threw away the junk lag screws that came with the racking. Consider yourself fortunate you can't find them.

 

[PoorUB]

My bet they were metric and marked 8.8 which is similar to SAE grade 5.

 

[matt_i]

GRKs are very strong, with about 2" of the thread engaged even in end grain they will self-countersink the head...even better than that when you engage the cross-grain as I think you probably will when finding overhead crossmembers.

 

[jack stand]

GRK!
I've seen more broken cheap *** lag bolts than the GRK RSS line. I have seen a few break, but we regularly use them multiple times for bracing.
They also are 100 times less damaging to 1 1/2" (2x) materials for shear or pull out.

 

[bscman]

GRK

I've switched over to them on many projects.
My overheads garage shelves and my steel gladiator garage cabinets are all hung with GRK. So handy, and tougher than tough.

 

[jack stand]

I've been using more and more of the Simpson line. Much easier to find 250 and 500 pc. buckets for a better price. The head is also a bit bigger diameter that helps the pulling power.

 

[theoldwizard1]

GRK have a tested load rating. Never seen anything for lag screws.

 

[cadunkle]

I used a similar style lag replacement, or structural screw with integral washer head, to ceiling mount a unit heater. I don't recall the brand or model but they have a hex head. I used 4 of them for a 45k unit heater (~65 lbs), screwed straight up into the joists. Easy install and seems solid.

I need to install a wall mount bracket to hang a mini spit. Probably weighs around 200 lbs. The bracket I have came with lags to wall mount to studs. I think I can hit three studs on the upper and lower brackets, so 6 bolts holding it up if ideal, or 4 worst case. Are these type of fasteners suitable for a wall mounting a couple hundreds pounds with the fastener in shear? I'm hesitant to use lags, I worry about backing out or loosening with vibration and the wood expanding and contracting with temperature and humidity. The alternative I had in mind would be to install blocking between studs and use six through bolts, but it would be faster and easier to just zip a few of these style of screws in without removing the interior wall, insulation, etc.

 

[duneslider]

GRK have a tested load rating. Never seen anything for lag screws.

Lags have a "tested" standard load. You can look it up. All lags should be made to the same spec and meet the minimum requirements. The problem with lags is that very few people use them correctly. Every size lag requires very specific pre-drilling. A lag that has a threaded portion and a smooth portion requires two sizes of specific pilot holes at specific depths. If you don't do it correctly you will end up with a compromised spec.

The GRK and Simpson lags are designed to not require pilot holes and have specific stated load ratings. I ask the engineers I work with to spec GRK or Simpson whenever possible.