SPAX Screws

[GMCGarage]

Anyone have experience with SPAX screws? I want to use them for sistering some floor joists, and have a collection that I can use. They say no predrilling, but I will be going into some older joists.
Thanks

 

[EOC_Jason]

I've never pre-drilled with spax, they go in quick and easy. Never had any splits or anything either but it wasn't super old wood.

If they are floor joists, you are going to have to use a ton of screws, or maybe consider using some lag bolts instead (that will have to be pre-drilled).

 

[GMCGarage]

I've never pre-drilled with spax, they go in quick and easy. Never had any splits or anything either but it wasn't super old wood.

If they are floor joists, you are going to have to use a ton of screws, or maybe consider using some lag bolts instead (that will have to be pre-drilled).

Im going to use adhesive as the main connection, the screws are more a clamping mechanism.

 

[LeeG]

I have been using SPAX screws for years. Between those and GRK, I almost never use anything else these days. They also have some 1/4" lag screws that are just about my exclusive choice for high strength joints.

 

[vavet]

I've used them a few times. Depending on what I'm doing and how accurate I want to be, I still pre-drill. Whe I was hanging the french cleats on my garage wall, I pre-drilled. I wanted the screws to be placed accurately for appearance and to make sure they hit the stud behind the drywall. For floor joists, I wouldn't worry about pre-drilling.

 

[GMCGarage]

Thanks. I have #14 screws, so they are darn close to a 1/4 lag.

 

[Falcon67]

Having sistered some real old rafters and joists, I'd be inclined to at least pre-drill to avoid any splits. Old wood gets hard and sometimes unpredictable.

 

[stonesfan68]

Those screws are great. I think they make a lag-screw substitute as well?

 

[Shiftless]

When sistering in a new joist, I like to pre-drill a passage hole so that when the screw bites into the old joist, it pulls the new wood tight. Also, get the partially threaded screws like these so there won’t be any threads biting into the new wood to possibly push the 2 pieces apart.
Also, the Torx Drive is great. I don’t use very many Phillips head screws at all anymore.
Simpson makes hex drive screws that are load rated for shear strength. My inspector insisted on those for a joist sistering job so I used them. Easy to drive in with a half inch corded drill.

If you use glue, you can use almost any screws you want to. Kinda like wearing a belt and suspenders.

But this is GJ, the home of overkill. . Maybe somebody here will suggest through bolting.

 

[NUTTSGT]

I used a few of them or GRK for the utility room remodel, my first real experience with them. I was impressed with those things, bad *** IMHO, as they went right into old native wood without an issue.

 

[driftpin]

"Quick & dirty" may-be possible, but I would suggest it is not the best. How much time can it take you to pre-drill? You will reduce the likelihood of snapping your fasteners for one.

 

[PhysicsDude]

I used SPAX screws for making cabinet drawers and some bookshelves and was REALLY impressed with them. For a nice finished product like cabinetry I like to predrill a small hole, or if I'm drilling them into the side of a piece of plywood, but they work fine without pre-drilling for the most part, especially for just joining wood beams like what you're talking about.

There's a lot of "gimmicky" stuff out there with bold claims, but so far I think SPAX is pretty legit.

 

[cheechi]

Any screw with the type 17 point doesn't 'need' to be pre drilled. I do often anyway, even if it's just a 1/8" for a #14 it can help.

For lags equivalent, I like the ledger lok better than Spax. I prefer the GRK R4 better than the Spax equivalent. They aren't bad screws by any means.

 

[frankthezapper]

Yesterday I took apart an old hardwood bench (maybe not made so long ago, but made with old timber) with this type of screw as the only fastening, there were about 5 or 6 joints that were split, mostly close to the end of mitres, so in old hardwood definitely predrill.

 

[Lelandwelds]

"Quick & dirty" may-be possible, but I would suggest it is not the best. How much time can it take you to pre-drill? You will reduce the likelihood of snapping your fasteners for one.

Deerwood, SPAX, GRK, etc. are supposed to be made from better steel and not snap like drywall screws. I haven't used them yet but the guy on the counter says you are supposed to run them in, back em out to clear the chips, and drive them home.

It takes more than twice as long to predrill.

 

[davewo]

I've been using Spax almost exclusively for a few years now. The only exception I can think of is when I needed longer truss head screws and GRK was available at the moment.

 

[alexb2000]

I love Spax.

I also use the GRK, especially their trim screws.

For structural work you might also check out TimberLOK

https://www.fastenmaster.com/products/timberlok-heavy-duty-wood-screw.html

Not using drywall screws for everything puts you ahead of the pack IMO.

 

[matt_i]

but the guy on the counter says you are supposed to run them in, back em out to clear the chips, and drive them home.

Sounds like he's been behind the counter too long of a time to give practical advice. Backing them out does nothing to assist the integrity of the joint and the manufacturer's instructions do not reference this technique.

The secondary "cutters" on the shank (the fast-thread) make it so that when trying to tighten up a joint, you don't have threads-fighting-threads with a gap in between. Instead, it purposefully cuts the threads closer to the washer-head to make these the weaker link so that when the screw head starts to bear on the timber, any gap in the joint wil close instead of the pilot threads stripping out. This makes some wood chips but they are left behind as chaff. It doesn't affect the ability to pull the joints tight.

I've put in easily 1000 of the GRK-RSS screws so have a small amount of practical experience.

 

[Boomer343]

Im going to use adhesive as the main connection, the screws are more a clamping mechanism.

What adhesive? Very few are qualified to be structural.

If you are driving into old fir etc I would be predrilling. I have drilled the new wood before installing as the old shoulders really dislike overhead work.

 

[Jackfre]

Spax, GRK or Simpson would all hold the wood. The recommendation on the Simpson makes sense to me as they are a rated structural fastener. Down the road it could matter to a new buyer or insurance, etc.

 

[6768rogues]

Whenever I am sistering floor joists, I through bolt them with carriage bolts. I just did some yesterday at a house my son owns. One through bolt out performs a number of lags, and drilling them in does not split the wood. Expansion and contraction does not work them loose and water does not weaken them, as it might with glue.

 

[GMCGarage]

What adhesive? Very few are qualified to be structural.

If you are driving into old fir etc I would be predrilling. I have drilled the new wood before installing as the old shoulders really dislike overhead work.

This is a serviceability issue, the original joist are structurally adequate.

I would think I will use a Henkel product. they have a few that are ICC-ES evaluated.