On 31/10/2020 18:07, pinnerite wrote:
From around the beginning of February, Mrs P and I will be moving into a
bungalow that is in need of lot of work. I do not yet know how old it is
but I am guessing from between mid-60s to early 70s.

The loft has glass-fibre insulation and is only partialy boarded. I
intend extend the boarding. I boarded my current one with bits of
chipboard let over from work done years ago. Well that was 5/8" board.

Now (soon) I shall need to buy new. It looks as though 18 x 600 x 2400 is
the default today.

The thing is I always aligned board edges along the centre of the joists.
So that would require joists at 600mm.

My house wasn't completed until May 1972 and its joists are at
16" (406mm) centres. The "new" bungalow may be the same age. Should I be
concerned if I intend to lay them at right angles to the joists?

You would normally run the long axis of the boards perpendicular to the
joists. So you would only potentially need to trim an end of a board if
the joist spacing is out. The board to board joins have the T&G profile
and so don't need extra support.

(you can make them stronger still if you glue them, but that is usually
overkill).


--
Cheers,

John.

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