Timber needles or small RSJ needles to support wall while do

[mediabuild]

Hello

Ive searched through the forums and cant quite find the answers im after.

Ive done my fair share of removing supporting walls and inserting RSJs / UBs etc. I use strong boys or timber needles depending on the job. I don’t use RSJs as needles and was just wondering who uses RSJs and when would you use steel over wood?

The timber I keep just for these jobs is around 1200-1500 long and rages from 10x3’s to 8x2’s.

Ive got a large opening on a double skin cavity wall to do and install 2 large UBs. Im just wondering if I should get some small RSJs to use instead of the timber needles? Ive done double skin walls before with timber and strong boys, and I know others who still do use timber, but do any of you guys use RSJs or maybe even scaffold tubes or steel box section?

 

[RonnyRaygun]

Hello

Ive searched through the forums and cant quite find the answers im after.

Ive done my fair share of removing supporting walls and inserting RSJs / UBs etc. I use strong boys or timber needles depending on the job. I don’t use RSJs as needles and was just wondering who uses RSJs and when would you use steel over wood?

The timber I keep just for these jobs is around 1200-1500 long and rages from 10x3’s to 8x2’s.

Ive got a large opening on a double skin cavity wall to do and install 2 large UBs. Im just wondering if I should get some small RSJs to use instead of the timber needles? Ive done double skin walls before with timber and strong boys, and I know others who still do use timber, but do any of you guys use RSJs or maybe even scaffold tubes or steel box section?

I don't do much of the actual propping but I know how to work out the forces onto the needles.

From the fag packet calculation I've just done, I wouldn't be using anything less than pairs of 8x2 timbers, 1m long, at 1m centres to support the rear of a property, including masonry, first floor, loft, and roof.

Some of you will probably tell me that you use less timber or longer timber, but there are pretty good factors of safety in timber design that will give a bit more capacity.

Even a 102x44 joist or a 100x50 pfc is stronger than the timber I mentioned above.

I wouldn't want to use scaffold tubes or small box section as it almost certainly isn't strong enough and would suffer excessive deflection potentially leading to cracking of the masonry.

 

[^woody^]

We tend to use 2x 2x4 nailed together as a needle for all domestic work

We'd only use a deeper needle if the props need to be further out for whatever reason

Never a scaffold tube and I can't imagine why a RSJ would be needed

 

[tony1851]

An advantage of timber needles is that, being softer than steel, they will cause less damage to the bricks actually being supported.

 

[noseall]

We use 4" x 4" old oak posts retrieved from a fencing job or double up some 4", 5" or 6" x 2"

 

[RonnyRaygun]

Woody & Noseall. What lengths would your 4x2 be and at what centres?

Just doesn't seem anywhere near strong enough at a metre long and metre centres.

Might go to show how generous the factors of safety are...

 

[themiddleagedun]

I've used both, but much prefer to use timber, say a 6x4, and I always screw the acrow to the needle. Steel-on-steel tends to spin and slip as you tighten the props I find. Also it's heavy 'n' numb to handle though obviously stronger...
Six-of-one 'n' half-dozen of the other...
Don't suppose that's helped really?..

 

[themiddleagedun]

Just remembered we did one last week, a 4.6m opening, and used 4 needles 2 steel, 2 timber. Just what we had to hand.
All depends on length of needle. We try to leave the width of a couple of scaffold board at the front for the props, whilst placing the rear ones close to the wall.

 

[stuart45]

Iv'e normally used 4x4 or 6x4 timber without problems, even when propping thick stone walls which are not as stable as brickwork. You can also nail the tops of the props to the needles.