Tim S wrote:
Huge coughed up some electrons that declared:

On 2008-10-13, Tim S wrote:
Timothy Murphy coughed up some electrons that declared:

I want to make a hole in a plasterboard ceiling
to get access to the roof-space in my one-storey cottage.
I have found that the joists are 1 foot apart,
and am thinking of making the hole a little under 2 feet square,
which would mean cutting one joist.
and putting 2 cross-pieces to hold the joist.

Is this a job I can do myself? Or should I get a builder.
I'm reasonably handy.

Any advice or suggestions gratefully received.


**** As always with free advice on USENET, please wait around for a bit
to see if there's are any refinements on what I'm about to write and make
sure no-one disagrees fundamentally with what's below. ****


Well - it sounds like a pretty standard loft-hatch arrangement.

I assume the joists are only holding the ceiling up?
Aren't joists normally under tension loads, because they're preventing the
eaves from being pushed outwards by the pitched roof?


That may be true. I'd assumed one could get away with the odd one or two
being cut as the affected roof rafters would be supported from spreading by
their neighbours (via the purlins and the numerous tile battens) and the
cut joists may pick up lenghtways support from their neighbours in similar
nefarious ways.

I'd be interested if there is a "proper" answer to this.


There is, but its entirely dependent on the exact roof layout.

But there is normally bags of redundancy, so go ahead and do it.



Cheers

Tim