Joist Hangers: too many holes?

[scottishjohn]

there are screws +screws

as in all things you need to get correct type and for the job, they would have a flat faced head ,not a countersunk head as in std wood screw + not from screw fix-or other cheap crap supplier with no wasting under head .

I would just use the nails  --but he wanted an option -there are options  correct-- screws to correct torque --not a problem  cos they have more surface area to grip  than an nail of any type--as you found when using nails on your cladding as i remember screws don,t work them selves out as nails can in some applications

I agree  though I would use the twist nails --its the cheapest + simplest solution 

 

[joe90]

Just read this on another forum from a professional.

 

 

Screws are made of a harder metal which is more brittle and thus has a much lower resistance to shear loads compared to the more ductile nails. Screws are not to be used for applications which have shear loads, unless the screw itself is rated for that application. This is particularly important for DIYers - there have been cases of injuries where people have built decks themselves and used screws for the joist hangers, only to have the whole thing fail under load with people on the deck. The manufacturer of the joist hangers usually specify the approved type of fasteners, but sometimes they have special screws rated for this application. Using regular wood screws (even though the shanks may appear thick) is a very very bad idea. If you don't believe me, fasten two pieces of wood with screws and another two pieces with nails. Whack them with a hammer perpendicular to the fasteners and see how long the screws survive. They usually break quite easily whereas the nails will bend at worst.
Screws are fine for non-structural applications (e.g. the blocking in stud walls or holding the top and bottom plates in place for compression loads) but professional framing contractors only use nails for two main reasons: (1) Nails are always approved for this application and (2) nails can be installed much much faster than screws. No professional would use a hammer - they all use pneumatic nail guns. I cringed watching some episodes of Grand Designs where the contractors were using handsaws and hammers for framing!

 

 

notice “manufacturer sometimes have approved screws”, I have searched for “approved screws for joist hangers” and come up with zilch!

 

@recoveringacademic can you not position the hanger and joist with a couple of screws and get an apprentice to whack all the nails in for you.

Edited December 5, 2018 by joe90

[Jeremy Harris]

8 minutes ago, scottishjohn said:

there are screws +screws

as in all things you need to get correct type and for the job, they would have a flat faced head ,not a countersunk head as in std wood screw + not from screw fix-or other cheap crap supplier with no wasting under head .

I would just use the nails  --but he wanted an option -there are options  correct-- screws to correct torque --not a problem  cos they have more surface area to grip  than an nail of any type--as you found when using nails on your cladding as i remember screws don,t work them selves out as nails can in some applications

I agree  though I would use the twist nails --its the cheapest + simplest solution 

 

 

Pretty much every type of wood screw will have a core diameter (which is the bit imposing the bearing stress on the timber) that is around half, or less, of the core diameter of a twist nail.  The exception are some types of concrete screw, where the core diameter is virtually the same as the nominal diameter.

[ToughButterCup]

Right, seems a good point to summarize -

 

Fixing (POSI in this case) joists to joist hangers and the wall-plate ( pole plate, rim joist )

In my case, first pimp your joists - to the agreed design with SE (Cullens) BCO and the wider BuildHub commentariat.

• Read the manufacturers specification in relation to fixing (in this case  for reference here : first document in the list ) 
• Twisty nails (Lady Bird Book speak for) sheradised twist nails are preferred
• Use screws to position the joist
• set up the laser to ensure correct level
• On POSIs, look for label indicating the top chord 
• check for bowed joists - when found (but not on a POSI), they should be placed so that the bow is upwards
• the vast majority of holes should contain a nail fixing (length and weight to specification)
• If in doubt, follow the spec

Looks like I need to practice a bit with a hammer - someone suggested using a long nose pair of pliers

(I have few enough fingers left, so I'll be doing that)

Edited December 6, 2018 by recoveringacademic
Correction of an error noticed by @mvincentd

[joe90]

Yes, that’s my vote.  ?  Another top tip, I like using a brick hammer (https://www.screwfix.com/p/magnusson-brick-hammer-20oz/5895v) , the head is square not round and it’s easier IMO to hit the nail using the corner of the square head, just thought I would put it out there.

[Ferdinand]

5 hours ago, recoveringacademic said:

Our joist hangers resemble a colander. Sooooooo many holes : 17 per side - 34 all told

Ain't got no Paslode machine gun, not likely to either...

 

So, folk-who-know-more-than-I-do, using screws or those twisty nails specified by the manufacturer, how many nails or screws do I have to use (per side) ?

 

17 is not a valid answer.  ( @Pete )

 

It's in Lancashire so according to Greenpeace you are now an existential-threat-due-to-the-earthquakes area, once they do more fracking.

 

Better make some more holes and put nails in those too !

Edited December 5, 2018 by Ferdinand

[MikeSharp01]

14 minutes ago, Ferdinand said:

existential-threat-due-to-the-earthquakes

Yes I had not considered that you are now officially in an earthquake zone, so you need to check that your SE has; the relevant experience, has designed with the 1 in 100 year event (or whatever) in mind and PI insurance.  

[Onoff]

A bit late for some...

 

 

https://www.ebay.co.uk/p/Nail-Gripper-Grips-Nails-Whilst-You-Hammer/28005957839?

 

or

 

https://www.prezzybox.com/nail-it-finger-saving-nail-holder.aspx?

 

etc

[jack]

2 hours ago, JSHarris said:

Pretty much every type of wood screw will have a core diameter (which is the bit imposing the bearing stress on the timber) that is around half, or less, of the core diameter of a twist nail.  The exception are some types of concrete screw, where the core diameter is virtually the same as the nominal diameter.

 

Screws also often have sharp junctions where the thread meets the core. This is a focal point for shear stresses (especially if the thread goes all the way to the head), which may be another reason why screws aren't appropriate in shear applications.

[PeterW]

I used to have a rare earth magnet glued on the end of a pencil - poke into bag to pick up a nail and easy to move out when I’d hit it once. 

[ToughButterCup]

Hmmmm, every challenge an opportunity. Let's see if I still have 6 working fingers after they are all in (935)

?

[mvincentd]

5 hours ago, recoveringacademic said:

check for bowed joists - when found they should be placed so that the bow is upwards

I dunno, but check that with supplier. Mine were all specifically marked to show 'top chord' and it wasn't optional to flip them.

[joe90]

7 hours ago, recoveringacademic said:

• check for bowed joists - when found they should be placed so that the bow is upwards
•  

 

I think that refers to timber joists, not engineered joists, timber twists etc but engineered timber is much more accurate so no bows should be found.

[Ferdinand]

20 hours ago, jack said:

 

Screws also often have sharp junctions where the thread meets the core. This is a focal point for shear stresses (especially if the thread goes all the way to the head), which may be another reason why screws aren't appropriate in shear applications.

 

Jack, have PM'd you.

 

F

[ToughButterCup]

17 hours ago, mvincentd said:

I dunno, but check that with supplier. Mine were all specifically marked to show 'top chord' and it wasn't optional to flip them.

 

Exactly right. Mine all have a yellow ticket on them, clearly marked showing the top chord. (list edited) 

[scottishjohn]

1 hour ago, recoveringacademic said:

 

Exactly right. Mine all have a yellow ticket on them, clearly marked showing the top chord. (list edited) 

would be interesting to check and see if they are all crowned a little--so when you load them they go down flat--in theory  

Edited December 6, 2018 by scottishjohn

[ToughButterCup]

And now down to practical nitty gritty bits....

 

The guidance from POSI says leave a 50ml gap between the wall and the first joist. Hmmmm.... look at this

 

 

There's no way even an eight-fingered self-builder like me can whack that hanger in place. So,erm ?

• Put the hanger in first?
• Get Debbie to do it? Put up with the moaning and gurning?

Its only the end of run / beginning of run joists that'll have this little quirk.

[ProDave]

The problem is nailing the hanger to the joist down that gap. So nail the hanger to the joist, slide the joist into position, then nail the joist to the wall plate.

 

A magnet on a stick to hold the nail, and 50mm is enough room to swing a hammer.

 

P.S.  To me the hanger looks too short. Every one I have done, the hanger is long enough to fold over at the top and also nail into the top of the wallplate

[Tennentslager]

As we say in Glasgow...and other places

"As hard as nails"

Not ard as screws...screw loose?

[joe90]

I’m with @ProDave on this one, and have done this myself, hanger fixed to joist first, difficult to hold the nail but you can swing a hammer in a 50mm gap. I like the magnet on a stick  idea ?, wot about https://www.amazon.co.uk/dp/B001C7NN86/ref=asc_df_B001C7NN8657405348/?tag=googshopuk-21&creative=22110&creativeASIN=B001C7NN86&linkCode=df0&hvadid=309816003291&hvpos=1o2&hvnetw=g&hvrand=7569780515085895972&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9045292&hvtargid=pla-425415221212&th=1&psc=1

Edited December 10, 2018 by joe90

[Jeremy Harris]

Talking of magnets on sticks, I have several pencils here with neodymium magnets glued on the ends.  Buy some pencils with erasers on the end, pull out the eraser and glue in a neodymium magnet around 6mm in diameter in the end with a bit of epoxy adhesive (Araldite or similar).

 

The pencils work as normal around the site for marking out, but will hold screws or nails for driving, without risk of hitting your hand, will retrieve dropped nails and screws, and as I recently found, will very accurately find buried plasterboard screws.

 

On the same topic, but related to cleaning up the site, I glued and screwed a 50 x 50 batten to the bottom of a broom handle and screwed a row of countersunk neodymium disk magnets to it, the ones that are around 20mm in diameter and intended for door catches.  I placed a heavy duty plastic bag over the end, with its neck tied to the handle, and had one of the young labourers drag it over the site for an hour or two.  He collected a decent pile of discarded nails, which were easy to remove from the magnets just by pulling the plastic bag inside out and pulling them off into a bucket.  This probably saved one or two tyre punctures I suspect.

[ToughButterCup]

13 hours ago, ProDave said:

[...]

P.S.  To me the hanger looks too short. Every one I have done, the hanger is long enough to fold over at the top and also nail into the top of the wallplate

 

The BCO and I both asked Cullens (hanger manufacturer) about that and were assured they are correctly designed 

[ToughButterCup]

40 minutes ago, JSHarris said:

Talking of magnets on sticks, I have several pencils here with neodymium magnets glued on the ends.  Buy some pencils with erasers on the end, pull out the eraser and glue in a neodymium magnet around 6mm in diameter in the end with a bit of epoxy adhesive (Araldite or similar).

[...]

 

Thanks @ProDave and @JSHarris both. I'll try the techniques you suggest. Got some araldite and spare pencils...

Lost a bit of sleep on this one last night. 

What's new eh? Nowt.

[ProDave]

7 minutes ago, recoveringacademic said:

 

The BCO and I both asked Cullens (hanger manufacturer) about that and were assured it was correctly designed 

It might be "correct" but I always tend to over engineer things and I just like the security of the hanger folded over the top of the wall plate and a few more nails to keep it there.

[ToughButterCup]

Hmmm.

There's a bit of me which thinks I should screw doublers to the ends of the joists. 

Maybe a triangle of plywood (right angle triangle) either side of 'endplate'.... hard up against the wallplate.