dennis@home wrote:
"Cash" wrote in message
...
dennis@home wrote:
"Cash" wrote in message
...
dennis@home wrote:
On Wed, 11 Jan 2012 10:34:52 -0800 (PST), GMM wrote:

I thought of putting a circular saw on its side and running it
along but that
doesn't look very feasible.
Any suggestions chaps?

Well I would cut several strips of ply the depth of the joist and
screw + glue them on either side so the tops are at the finished
height. Then I would get a hand saw and lie it across the ply and
saw the top
off. Stager the joints in the ply and use it as the reinforcement.

Dennis,

It's rare for me to openly contradict another poster here, but with
all due respects, I think you really are talking through your hat!

In this case, they reinforcing material should be bolted to the
joist and should, at the very least be of equal thickness to the
original (and *NOT* "several strips of ply") doh!

Well I didn't say how thick the ply is!

Well that really speaks volumes on how little you know about the
subject - or of correctly responding to a post. Read my first post
here in response to the OP, and you will see what my initial
question was (repeated here) - rather vital information for
structural repairs wouldn't you agree?

-----------------------------

GMM,

How long, wide a[nd] [1] deep is the joist itself - (is the
measurment you gave -
the corridor or joist length)?

[1] Error in my OP corrected here
----------------------------

You really shouldn't argue unless you know how thick the ply is, how
long the ply is and what load is on the ply.

Please show me where you specified those dimensions in your response
to the OP's question. Oh, you didn't and as both the OP and myself
have yet to develop ESP, how are we to read your mind?

I can assure you that three pieces of 18 mm ply on either side would
replace 20 mm of a joist.



Now how long and wide should those three pieces of "18mm ply" be,
what glue (and preparation of the joist and ply) would you use [2] -
and what type, length, diameter and metal of screw would you advise
to fix that ply And just how do you expect a few " bits of ply, screws
and glue" to
take the load of a trimmed joist of unspecified size and also
prevent further movement?

[1] Epoxy, PVA, casein, animal - or perhaps the more modern
No-Nails type or even silicone mastic.

And as an old carpenter, I can assure you that unless you used stress
graded plywood, industrial glues, correct mechanical fixings and
design calculations - I would suggest that you are wrong.

And as for advising the reducing any load bearing piece of timber
without being told the size of it, its unsupported span and live
and dead load carrying well...

Well if you are that worried then its a lot better than taking 20 mm
off and it will resist further warping.

If you believe that, then you have little knowledge on the actual
mechanics of timber usage in construction work.

You really don't have a clue.

Rather more than you I believe Dennis,

I suggest you lookup engineered joists to see just how strong they
can be.

That's a far different animal from the "repair" you suggested.

There is bugger all difference.

Isn't there, from my experience there is a huge difference between a
properly engineered pywood joist and sticking a few bits of ply on the sided
of a dimension (or even rough saw) timber joist.

You just don't understand what I said.

What's so difficult in understanding gluing and screwing bits of ply onto
the side of a joist?

Like being the depth of the joist and along it length, all of it!

I will accept that you said the depth, but out of curiosity where did you
say "along the length of it" in your post (reproduced here)?
----------------------------------------------
"Well I would cut several strips of ply the depth of the joist and screw +
glue them on either side so the tops are at the finished height.
Then I would get a hand saw and lie it across the ply and saw the top off.
Stager the joints in the ply and use it as the reinforcement."
_____________________________

Most engineered joists are an I beam, the top and bottom are there to
stop the central supporting beam from twisting.
If you do as I said then you have the equivalent of two beams, one
either side with the existing beam stopping them twisting.
Now show why you think its wrong.

Where is the "top and bottom" of the repair that you suggested? You simply
advocated fixing plywood to the sides - so can you show *ME* how your
suggested repair corresponds to an engineered plywood "I-beam"?


As for "looking up engineered joists", I studied that subject some
forty five years ago as part of a 5 year City & Guilds indentured
apprenticeship [2] - and used some of the stuff in later years
during works on public buildings.


Shame you can't apply it then.

Shame you can't apply the basic principles of asking for more relevant
information about a job before shooting from the mouth.

As for applying them in 'the real world' I have - have you done so, or is it
all theoretical with you via Google?

Now Dennis, it's interesting that you have not answered one of the technical
questions that I have posed to you.

Cash