As irrelevent as it is to this topic, you CAN notch the underside of JOISTS in the prescribed zones.It's nothing directly to do with anything electrical, but notching of the underside of joists for anything (pipes, cables or whatever) is not permitted by the Building Regs because of its effect on the structural integrity (i.e. 'strength') of the joist. Notching of floorboards, which is what skenk mentioned (although, I presume, not 'seriously') doesn't (or, most certainly shouldn't!!) happen.
Kind Regards, John
It doesn'tYou also get glued floating t&g chipboard floor with no mechanical fixings, not that I think the ease of finding floor/ceiling joists has anything to do with the regs under discussion.
Yes - but the last sentence of the quote:As I said, it makes sense to me that the RCD sockets have to comply with both Standards, otherwise most of BS 1363 would have to be repeated in BS 7288.
It does appear to - but I confess that I had assumed that it had been badly written, and that what it actually intended to say was ...Yes - but the last sentence of the quote: .... states that they may only be used where they are not needed.
That's contrary to what most people believe. To my surprise, Approved Doc A is silent on this matter (refering one to TRADA tables or various Standards for details concerning all structural woodwork) but many LABCs produce Technical Guidance Notes which indicate that only the upper side of joists (and in certain places and sizes) may be notched. For example, this from the Hertfordshire LABC (click here) ...As irrelevent as it is to this topic, you CAN notch the underside of JOISTS in the prescribed zones.
I looked at several, and get the impression that they are all quoting from the same source (although none say what that is), since they all say very much the same thing.Does it depend where you live? Different councils; different rules?
That seems consistent with (not different from) the Hertfordshire one I posted, given that it says:
Maybe, but the fact is that a notch of a given size and (lateral) position on the bottom of a top-loaded beam (such as a floor joist) has a much greater impact on the structural behaviour than does notch of the same size and position on the top of the timber.Thanks for that. Rightly or wrongly, there are a lot of diagrams on the internet showing notches cut in the underside of joists, supposedly allowed at the same intervals as notches at the top - although they do stipulate you must not have notches in the same spot both top and bottom.
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