You wouldn't need to wear a mask/boiler suit just to access the loft.
It's when you disturb the fibreglass and it sends up particles that you
need a respirator. Once the dust has settled, you'll be fine.
Once things have settled down, a quick brush on one will not dislodge much.
It's when it's being handled in vengeance that things get messy. For normal
access, if you are not touching the stuff on purpose, it would be fine
I cannot disagree that what you say is theoretically correct.
The central part of my loft is boarded, over insulation level
with the joists, with lots of stuff stored on it. Either side has
a substantial covering of insulation. One cold day I went all
round the house with a temperature measuring gun, to see if I
could find any significant cold spots. I could not detect any
significant temperature difference between those bits of ceiling
beneath central boarded area, and those with thicker insulation.
Perhaps plastic boxes full of books, carpet off cuts and empty
cardboard boxes aren't such bad insulation after all.
As my roof has a fairly shallow pitch, lifting the loft boarding
would be pretty impractical, as the headroom would no longer be
Chris J Dixon Nottingham UK
The central heating was cycling, so the house was being heated,
but temperature had stabilised.
Thinking about the physics, and simplifying slightly, if the air
space in room and loft both have uniform temperatures, which is
practically true, then in any areas where there is more heat
flow, due to lower insulation values, the surface temperature of
the ceiling will be lower.
Isn't this simply the reverse of examining walls with an
infra-red camera? Room and outside world temperatures are
constant, but in areas of poor insulation, the wall is warmer.
Basic physics: greater heat flow requires greater temperature
Chris J Dixon Nottingham UK
To provide storage and access consider:
Locate joists and attach vertical timbers between joists and high points on
Above the required insulation level, add horizontal timbers between new
vertical timbers and lower/outer point on rafters.
Rest boards on new horizontal timbers to provide elevated shortage.
(I did this before insulating the loft - much easier)
For the walkway, remove a strip of the fluffy insulation down to top of
Replace this with rigid celotex-type insulation (50 thick) and board over
for access walkway.
What sort of timber would I need for this and how many? Before the
insulation, the weight of the storage was spread across several joists on
the chipboard boards and stacked, sometimes 8 banana boxes deep. I don't see
it holding the weight myself.
On Wed, 17 Mar 2010 19:13:55 +0000, stuart noble wrote:
I would. Loft "floors" are rarely built to the same strength as a
real floor, all it has to do is hold up a bit of plaster board and
As for the OP it depends what is in those banana boxes. Books weigh a
lot, general loose household "junk" much less.
Neither weight as much as several human beings having sex, or a bath
full of water, or a grand piano, which are the typical peak loads a
normal floor has to cope with.
I've bent a 5 ton pulley suspended off a 2x4 beam trying to get a car
engine out of a car. We raise the car instead..so that's where things
BREAK. i.e the typical 6x3 joist will over a short span easily take a
couple of tons. It will bow like shit of course.
But it wont break.
So you don't want more than about a cubic meter of books (probably 1/2
ton)on a single joist.
I don't own more than a cubic meter of books., that's about 500 LARGE
paperbacks I'd say. Maybe more.
The fibres are very nsastyy. wear dust mask.
what you SHOULD have done, is aaksked first. The BEST way to do this is
to fill between existing joist, then screw more at right angles, and
fill between those then sheet over with something cheap like floor grade
chip to help seal from draughts and carry any loads. And keep dust from
the glass wool or water it is, down.
I would still be tempted to install cross joists and plate anyway if you
Either method works. Crossed timber is a lot weaker for a given amount
of timber than new timber running on top of the existing joists. The
latter strengthens and stiffens the floor stucture considerably, and
thats a definite good thing if you're using the space for storage -
7cm joists are feeble.
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