On 18 Jun 2004 15:42:44 +0100, John Richer wrote:

(3) Make the joists deeper by adding 2x2s or 3x2s on top to get more
insulation, then reboard. This is probably too hard, and I'm
hoping 4 inches of insulation is enough.

100mm is pretty thin by modern standards I think they recomend 200mm
these days but that would be open on the exposed sides the boarding
will have some insulating effect as well.

It's more faff to lay extra timbers but on the whole probably better.

You want to lay them across the existing timbers not along. Fill to
the top of the existing ceiling joist with glass fibre or WHY. Lay the
new timbers then fill to the top of them. This means that the only
direct through timber path from the ceiling to flooring is the small
areas where the timbers cross rather than the full area of each joist.
Laying the new joists cross ways also helps to spread the load across
the whole ceiling as well. Ceilings are not normally designed to take
much weight...

If you use celotex or similar you need to arrange ventilation between
it and the ceiling to avoid possible damp problems. Glass fibre is
breathable.

--
Cheers
Dave. pam is missing e-mail