At what interval would one normally screw chipboard (18mm t&g) to floor
joists? What would be a suitable screw length/size ?

Also... what (if any) would be a recommended expansion gap around the
perimeter of the chipboard deck ?

and... lastly.... is there any type of "de-coupling" tape or something
that could be run along the top of the joists (2" x 8") which might help
reduce transmited noise through joists to ceiling below?

TIA.

Pete
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Pet @ www.gymratz.co.uk wrote:

At what interval would one normally screw chipboard (18mm t&g) to floor
joists? What would be a suitable screw length/size ?

I use 10 gauge 2" screws on a 400mm grid. Screws any lighter or shorter
are not up to the job.

Also... what (if any) would be a recommended expansion gap around the
perimeter of the chipboard deck ?

Chipboard is fairly stable with humidity changes so you are only looking
to take out thermal effects which will be small. Allow half of 1% of the
room dimension at each edge.

and... lastly.... is there any type of "de-coupling" tape or something
that could be run along the top of the joists (2" x 8") which might help
reduce transmited noise through joists to ceiling below?

Don't know what to suggest...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
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John Rumm wrote:

I use 10 gauge 2" screws on a 400mm grid. Screws any lighter or shorter
are not up to the job.

I'll get some in.

Chipboard is fairly stable with humidity changes so you are only looking
to take out thermal effects which will be small. Allow half of 1% of the
room dimension at each edge.

It's going over UFH - Main room is 6M x 4M
half of 1% gives 30mm surely that can't be right to have 30mm gap on
each end can it? The screws wouldn't let it move by anywhere near that
amount.... would they? :¬(

and... lastly.... is there any type of "de-coupling" tape or
something that could be run along the top of the joists (2" x 8")
which might help reduce transmited noise through joists to ceiling below?


Don't know what to suggest...

Not such an issue as I wasn't planning for this "extra" but thought it
might help to have a few mm of somethingbetween deck & joist.


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Pet @ www.gymratz.co.uk wrote:

and... lastly.... is there any type of "de-coupling" tape or
something
that could be run along the top of the joists (2" x 8") which might
help
reduce transmited noise through joists to ceiling below?

It would be nice if there were. Youre screwing the board which will
couple it rigidly. If you want to experiment you might try gluing the
T&G chip together like a floating floor, and under it gluing something
flexible and stiff onto the joists. Thin stiff expanded polystyrene
might work, though I doubt it. Microcorrugated plastic sheet strips
would be a lot moer likely to work. I'm not convinced, but it may help.
If it squashes flat it wont.

For a proper solution, floor with somthing thin and cheap, eg half inch
chip, then lay underlay, then put your floating chip floor on. This
will work.


NT

Pet @ www.gymratz.co.uk wrote:

It's going over UFH - Main room is 6M x 4M
half of 1% gives 30mm surely that can't be right to have 30mm gap on
each end can it? The screws wouldn't let it move by anywhere near that
amount.... would they? :¬(

Hmmmm, nope you are right that don't sound right....

OK lets look up some figures. According to:

http://www.amazon.co.uk/exec/obidos/...ternodeltdcomp

Wood has a linear expansivity of 3 to 30 x 10 ^-6 / K (depending if we
are talking cross or along the grain)
Alas can't find a figure for chipboard explicityly or the resin
component of it.

In chip we will get a random set of grain orientations - so we may as
well take 30 as the worst case.

If you take your temperature swing as being 30 degress say that would
give a variation of:

30 * 10 ^ -6 * 6000 * 30 = 1mm

So even if the resin causes total expansion to increase by a factor of
10 (unlikely) then you need a total of 10mm say. or 5mm each end of the
long axis of the room. Given some will be available in the joints you
can probably reduce that still further. i.e. cut it to fit and allow the
natural error in cutting to give you the gap!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Pet @ www.gymratz.co.uk wrote:

So even if the resin causes total expansion to increase by a factor of
10 (unlikely) then you need a total of 10mm say. or 5mm each end of the
long axis of the room. Given some will be available in the joints you
can probably reduce that still further. i.e. cut it to fit and allow the
natural error in cutting to give you the gap!


Sounds better John.
:¬)

Many thanks


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wrote:

For a proper solution, floor with somthing thin and cheap, eg half inch
chip, then lay underlay, then put your floating chip floor on. This
will work.

Following my earlier post. I re-stumbled upon the
http://www.customaudiodesigns.co.uk/
web site.
They do a 5mm x 50mm Neoprene strip, but like you say, probabally best
solution is scre chip down as normal then use their acoustic unerlay or
matting stuff between chip + floating floor.

Inter Joists is pretty full as it is with 100mm loft insulation, 9mm ply
on battens, then 45mm cellotex and a final 4:1 16mm screed for heat
transfer medium from UFH pipes. So it's just the final flooring
de-coupling with minimum thermal resistance I'm looking for.

Just sent the customaudiodesigns folks a qestion as to best solution.

Cheers
Pete


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In message ,
"Pet @ www.gymratz.co.uk" wrote:

At what interval would one normally screw chipboard (18mm t&g) to floor
joists? What would be a suitable screw length/size ?

Also... what (if any) would be a recommended expansion gap around the
perimeter of the chipboard deck ?

and... lastly.... is there any type of "de-coupling" tape or something
that could be run along the top of the joists (2" x 8") which might help
reduce transmited noise through joists to ceiling below?


Two things occur to me:

1: If you are screwing every piece down to every joist with several
hefty screws, surely it simply *can't* expand enough to warrant much of
a gap? Isn't it only floating floors which need to move in this way?

2: If, as NT suggests you lay it floating then you may find a product
like this helps, though it is expensive, and won't solve all your
problems:

http://www.studiospares.com/productd...id=&hidden 1=

(If that doesn't work, search for items 406-070, 406-670, 406-080 and
406-680)

This stuff is Neoprene strip 50mm wide, 13mm deep at around £4.45+VAT a
meter (£3.75 50m.)

For the full "floating room" effect, as seen in the occasional recording
studio, try an Auralex U-Boat:

http://www.studiospares.com/productd...id=&hidden 1=

(Item 461-150). £3.25+VAT each, or £2.49 if you need 25 or more. They
are designed to be used *under* the joists on top of the
piers/walls/whatever, but I see no reason why they couldn't be used on
top of the joists under the flooring, though of course said flooring
would then be supported at points rather than all along the joists.

Or you could just fit a thick underlay and a decent carpet :-)

Hwyl!

M.

--
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.... I tried switching to gum but couldn't keep it lit

Martin Angove wrote:

Or you could just fit a thick underlay and a decent carpet :-)

Then my heating wouldn't work!

:¬))

Thanks for the pointers though.


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Martin Angove wrote:

This stuff is Neoprene strip 50mm wide, 13mm deep at around
=A34.45+VAT a
meter (=A33.75 50m.)

Sounds good, though a bit pricey. A 10x16' room might have 100 ft of
floor joist, 30m, =A3133.50, well ok, not too bad.

Theres only so much aborbing you can do like this though, it will never
equal the performance of separate floor and ceiling structures. But I
bet it would help significantly. Using both methods together would be
even better.


NT

In message . com,
wrote:

Martin Angove wrote:

This stuff is Neoprene strip 50mm wide, 13mm deep at around
£4.45+VAT a
meter (£3.75 50m.)

Sounds good, though a bit pricey. A 10x16' room might have 100 ft of
floor joist, 30m, £133.50, well ok, not too bad.

Theres only so much aborbing you can do like this though, it will never
equal the performance of separate floor and ceiling structures. But I
bet it would help significantly. Using both methods together would be
even better.


Well yes, that was sort of the point I was trying to make. Having said
that, I don't think (from my reading of the post) that the OP is
interested in *complete* isolation, just a way to reduce impact noise;
which you'll get a lot of walking on a hard floor.

I worked for a while at the local radio station in Cardiff which was
built in the early 1980s to what were then very strict IBA guidelines;
it was at the time when the IBA were still trying to prove that they
were technically "better" than the BBC and so specifications for all
sorts of things were very high.

The building was a concrete and brick ex-warehouse. The studios were
completely separated structures inside this; a concrete floor was cast
on top of brick pillars and separated from them with thick chunks of
rubber (or something similar). The walls of the studios were brick
(brick-cavity-brick IIRC) and the ceiling was a concrete/straw/metal
mesh mess which was a pig to drill through. Hung on the inside walls of
the room were accoustic boxes which were about 1ft square and 6" deep,
filled with fiberglass and randomly with a "pegboard" front or a
half-inch wire grid front. As many furnishings as possible had soft,
padded covers.

Windows were three panes of glass. The first two were effectively in the
studio room; the second of these was angled at something like 15
degrees and there was sound absorbing material around the edges of the
gap. After that pane there was a hefty fiberglass-cloth-type gasket and
a final pane of glass to the public area. There was a two-door "airlock"
to enter the room, each door weighing an absolute ton as it was filled
with sand.

All services (electricity, audio) entering and leaving the room were on
slack cables and the holes were sealed up with something like expanding
foam.

Air conditioning was by oversized ducting to give a very low airflow
speed but still deliver the volume required. The ducting was decoupled
with flexible sections and accoustic barriers from the adjacent studios.

All in all a very complicated (and impressive) setup. Still had a few
faults; the air intake for the aircon was at ground level in the car
park so you had to hope that whoever parked next to it had a
well-serviced engine!

The new studios weren't half so fussy, but they do the trick. After all,
with the microphone open for probably less than 5 minutes an hour, it
doesn't matter so much, does it?

Hwyl!

M.

--
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Two free issues: http://www.livtech.co.uk/ Living With Technology
.... I idiot-proof my programs, but then along comes a bigger idiot.