Does anyone use lag screws anymore?

[AaronMcD]

I see talk of lag screws in the code and online, and have heard older engineers mention them (I'm 37). I've seen them in stores, so someone must be using them. I've never specified them and only twice had a request from a contractor to use them. However, neither of those 2 times were a substitution request. They were both suggestions for some additional thing during CA. Every contractor I've talked to prefers structural wood screws such as GRK or SDS.

So does anyone still use lags? They seem like a royal pain to install and easier to mess up installation.

http://www.hellodwell.design

 

[jittles]

Not here.

 

[dik]

I have clients that still spec them... I offer GRK or SDS as an alternative and ASSY fasteners by MTC. They are often used to secure handrails to wood walls and I prefer a FH screw instead of a hex head screw. I think it's just a slow change over the last decade or two.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[manstrom]

Only for high tension connections. SDS type screws are the new norm. The ship is just slow to turn.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[XR250]

I still spec them in certain situations and I know i will get flamed for this. Around here, the lags have the shank the same diameter as the threads. In situations where the load is low and I want to attach a band to brick veneer without access from the inside for thru bolts, I specify lags and here's why.... For a 3/8" lag, the installer can drill a 1/4" hole in the brick and band (as a pre-drill for the band), then go back and re-drill the hole in the brick for 3/8". This gives a nice bearing surface for the lag - something you cannot do with the new types where the threads are upset. Sure, it puts all the vertical load in the brick, but it ends up there anyway with thru bolts so big deal. Yea, I know Simpson has that new thingy for this situation, but it is fiddly and. I feel that the chance of that getting installed wrong is pretty high.

 

[phamENG]

In some cases (jobs with government funding, mostly), spec'ing proprietary fasteners or systems can be a complicated process as they require either multiple possibilities (3 is often the magic number) or you have to go through a bunch of paperwork and prove why that's the only one that can be used in that situation. So in those cases, it can be convenient to just spec a generic lag screw and let the contractor suggest a sub.

In any other situation - no. I spec proprietary screws or through bolts. They are okay for interior applications where moisture variation is low, but exterior connections can work themselves loose with moisture and cyclic wind loading.

XR - I've spec'd the Simpson bracket and it was used properly (or so I understand). There are other manufacturers that have similar brackets, though they're geared more toward exterior insulation applications where you have to support a ledger or band on the outside face of 9" of foam. I've also had the contractor remove brick every few feet and install blocking to fasten through. That seems to have worked well. In some cases I'll justify fastening to brick veneer for a first floor deck low to the ground, but I stopped doing it for elevated work (had a boss teach me it was just fine, so I'm sad to say there are a few out there that I worked on). After getting into some forensic work and seeing buildings where veneer just fell off the wall due to improper brick tie installation or corrosion...I've come to really appreciate why the code says not to load brick veneer.

 

[XR250]

After getting into some forensic work and seeing buildings where veneer just fell off the wall due to improper brick tie installation or corrosion...I've come to really appreciate why the code says not to load brick veneer.

In that case, the lags would be helping as they would be acting as brick ties
I only use this tool in limited situations.
I'm curious what the blocking is doing for you? Was is fastened to the band and bearing on the brick?

 

[phamENG]

Touche!

No, it was fully fastened to the band with a gap below it. The the new ledger was installed fastening through it and into the existing band. The load path isn't the prettiest, but it gets the job done. It only works in older houses with essentially no air space. Start introducing insulation and 2" air spaces and the idea falls apart quickly.

 

[XR250]

The load path isn't the prettiest, but it gets the job done.

LOL
My thinking is that code allows the use of thru bolts -which ultimately bear on the brick so it is no worse off with the lags - other than pullout is not as great.

 

[phamENG]

code allows the use of thru bolts -which ultimately bear on the brick

I disagree with you here. I've always interpreted it as through bolts are NOT permitted BECAUSE they bear on the brick. I've seen some attempts to mitigate it like using pipe sleeves, but that sort of thing only works if you can pretension the bolt. Otherwise it's worse than bearing on the brick.

Now if there's a provision out there somewhere that I missed, please let me know.

 

[dik]

I recall one episode of "Holmes on Homes" where his guy was installing them in predrilled holes with a hammer...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[XR250]

@Pham...

 

[phamENG]

Interesting. I love a lot of the changes NC made to the IRC - especially the appendix for coastal construction. I use it all the time as a template for projects in similar conditions here in VA. I don't so much love that one.

Here north of the border we don't have an Appendix M. All wood deck material is contained at the end of Chapter 5, and it specifically states that deck ledgers are not to be supported on brick veneer.

 

[XR250]

Good to know that is an NC only thing - albeit, not surprising!