Drilling trough RSJ's

Hi All,

I need to re-route a 1.5mm T&E, it was originally run between the floorboards and copper c/heating pipes that are on top of an RSJ. This cable runs 90 degrees to the RSJ and copper pipes. This installation eventually went BANG and blew a hole in the pipes. I cant seem to find any regulation about drilling through an RSJ, all i can find is joists. Does anyone know much about drilling through these? The alternative to this is very hard work and would not pay!!!!!Pray

THANKS

RSJ's shouldnt be drilled at all as they are not designed to be drilled through when holding a weight load.

AndyGuinness

Usually you'll find an RSJ has been calculated specifically for the job, or near enough. You'd usually have to consult the designer or a structural engineer to egt the OK to drill RSJ's. I tend to go round them, think I've only drilled one, and that was at the instructions of the builder\designer as the builder forgot to tell us about some cables that needed running in on a new build.

Have to admit, I always thought drilling RSJs was a no, no due to structural tolerences.

bigs

From my old contracting days many moons ago i always thought that you could only drill a roll steel joist if you were going to tap it then insert a screw / bolt into said tapped hole.However i am aware that builders often drill rsjs incert wood into webbing then use a long bolt and nut to fix timber to rst i dont think they go to the bother of tapping the rsj,therefore i dont think 1x 10mm hole drilled and filed would be too detramental to an rsj

Some builders will have a hole blown through it with oxy-acetylene for pipes and cable.

Whether its OK is another matter.

in the words of amy winehouse, no no no.

Its upto you mate, drilling a very small hole will probably do nothing to the rsj. But if something does happen to it, all eyes will be on you if it was your fault or not.

I have actually seen them with pre drilled holes for services, however I would assume that this was taken into consideration and the required calculations would have been done to compensate.

I know some one who does all the calcs for these, I will ask him tommorro and update you on what he says.

(too late now, he is a friend but not one who would forgive a call at 10:30 at night)

IF you drill it, go for the middle!

Just got back home and I spoke to my mate about this and this is what he says.

If the RSJ is a new install done in the last 10 years or so it would have been calculated for all stress etc etc, there is no detrimental effect in drilling through the RSJ and will not weaken it.

Common practice is to "blow" holes in them to join one beam to another, which is just the same.

I would treat it just like a wooden beam, with proper spacings etc.

Just got back home and I spoke to my mate about this and this is what he says.If the RSJ is a new install done in the last 10 years or so it would have been calculated for all stress etc etc, there is no detrimental effect in drilling through the RSJ and will not weaken it.

Common practice is to "blow" holes in them to join one beam to another, which is just the same.

I would treat it just like a wooden beam, with proper spacings etc.

Click to expand...

Well I am glad you have said that because on a few jobs I have had to cut a few holes as there has not been an alternative but I would rather not as they are a pig to drill.

one of our surveyors wanted me to drill a 100mm hole in an RSJ to fit a fan. thankfully he got sacked shortly after(not for this in particular but for generally useless).