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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorandyman99
    • CommentTimeJul 24th 2018
    I need to notch lower floor joists for 22mm CH pipes. These will go beyond the permitted depth, my joists are only 4" deep. I've found these


    Do they look suitable to maintain joist integrity? Or does anyone know of other (cheeper!) options?
    • CommentAuthorbarney
    • CommentTimeJul 24th 2018
    Can you not run under the joists in the floor void - or drill holes in the joists and use a plastic pipe

    Personally, I'd not be cutting 25% of the joist depth away - at least not unless you like living on a trampoline

    Typically, you would want to limit any notches to 0.125 x the joist depth - and position it no more than 0.25 x span from the supporting ends

    If it is in a floor void, you may need even bigger notches if you intend insulating the pipes

    The product you link to is just a pipe clip, with a nail plate - it doesn't restore joist strength (or at least not by any significant value)


    • CommentAuthorowlman
    • CommentTimeJul 24th 2018
    +1 what Barney said; you could also look at putting a tight fitting "pit prop" of some description under each joist down onto the site concrete below. Do that coupled with drilling holes and using plastic pipes.
    • CommentAuthortony
    • CommentTimeJul 24th 2018
    Bigger joists for me or add 25mm battens above or below to accommodate the pipes - ie no notches
    • CommentAuthorandyman99
    • CommentTimeJul 25th 2018
    Thanks all, even drilling holes is not within regulations, OD of 22mm plastic appear to be 30mm and max drilling hole is 0.25 x joist depth. Raising the floor is a bit extreme at this point. May be drilling holes and extra "Pit Props" would work. Additionally there are already notches for 15mm pipe in the same span. If adding an extra prop in the middle halves the effective span, that would be OK and a nice simple solution. I have a structural engineer visiting this friday for other issues, so will see what he thinks.
    • CommentTimeJul 25th 2018
    Posted By: andyman99Raising the floor is a bit extreme at this point.

    But can you not run the pipes under the joists?
    • CommentAuthorandyman99
    • CommentTimeJul 26th 2018 edited
    Posted By: djh
    Posted By: andyman99Raising the floor is a bit extreme at this point.

    But can you not run the pipes under the joists?

    Insulation is mainly between the joists, so the simplest way would be to put the pipes thru the joists. I could adapt though, just for that span I guess. The oversite is 200mm below the bottom of the joist. I could create a tray lower down and get some insulation in along with the pipes.
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