# Forum Home Renovation Sub Flooring  Question about Pryda Joist hangers and nails

## alex999

We are owner builders and we are at the stage of putting our joists down. 
We are using Hyjoist 300 beams onto top mounted and face mounted Pryda joist hangers. 
The Pryda installation guide tells me I should use 40 mm x 3.75 mm nails or equivalent. 
My question: what does "or equivalent" mean. 
I would like to use a nail gun to save time and generally the nails are 50 x 2.8 mm. The extra length of the nail is no problem, but my concern is does the 50 x 2.8 provide the same level of fixing as the 40 x 3.75? 
I plan to ring Pryda up on Monday to ask but as I found this forum recently I thought it would be nice to hear from people with practical experience. 
Alex

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## DJ's Timber

OBBob went through all of this not that long ago. Have a read of this thread here

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## UteMad

Ring paslode they have a nail to do it for the duofast coil nailer but it does wear the piston driver a bit faster than nailing into timber.. 
Paslode is at ingleburn Nsw if your in Sydney its 25mins south on the M5 
cheers Utemad  www.dialadeck.com.au

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## OBBob

Geese I opened a can of worms!  :Smilie:   
How many do you have to do ... it's isn't that hard when you get into it ... mind you I'm still growing out the black thumbnail on my left hand!!

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## alex999

Many thanks for the replies. I went through OB Bob's thread and also rang Pryda. The technical people at Pryda emailed me instructions on how to use a nail gun with their hangers - with details on how close the nails can be to the edge of the hanger and the number of nails required, etc. 
In the end we did it the manual way.  
cheers
alex999

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## roy

It seems every time  abalcony collapses it was hanging on bloody joist hangers, should be made illegal

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## OBBob

> It seems every time abalcony collapses it was hanging on bloody joist hangers, should be made illegal

  Gees that's encouraging!  
Oh well, probably depends oh how you use them. I have full span bearers that sit on the top plates ... so they should go anywhere, then the hangers are just supporting short joists between.  
I can see, however that supporting the whole structure via joist hangers may not be the best idea. But I think they have their place if used correctly.

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## Pulse

> It seems every time  abalcony collapses it was hanging on bloody joist hangers, should be made illegal

  Roy what's your alternative suggestion and basis for that claim? I don't think skew nailing cuts it. 
Cheers
Pulse

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## OBBob

Hi Alex 
Many of the Pryda brackets are not meant to be installed with a nail gun because the force of teh gun damages may damage the nail heads. That said, the load on the joist hangers is probably not as significant as some others. The other reason is that they already have holes punched in the brakets and without a special tool you wont line your nails up with those hole, which must weaken the brackets somewhat. 
There was much debate about this a few years ago on this forum, so you may be best just checking what Pryda recomend. Alternatively, get your self a nice Estwing hammer and an MP3 player and get on with it!  :Smilie:   
OBBob

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## Stan 101

Most if not all fixings can be installed with pneumatic nailers. 20% more nails are required and care must be taken to drive the nail within edge distance tolerances. 
If you have a look at joist hangers in a span table or load table, you may very well be suprised at their ability under dead load. Generally the governing factor becomes the supporting member wanting to rotate, not the joist hanger failing.  
The rotation issue can usually be overcome by nailing a timber or strapping from the supported member back to the supporting member to counter this rotation effect.  
cheers,

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## Stan 101

I realise the original post was a few years old but is still relevant. To help prevent squeak, apply a dob of liquid nails or silicon to the top side of the horizontal flange of the joist hanger. 
In the case of the top and face mount brackets, also driving a screw from the underside of the joist hanger can seriously help prevent squeak years down the track.  
cheers,

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