does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?
What if the 2x2 was at right angles to the 4x2?

Gluing and screwing to build up the height of a joist does not give you
the same strength as if the full height was one piece of timber. Beams
can be built up as glulams, but only with very carefuly controlled
design and construction. If you're working to an engineers
specification for joist dimensions, it's very important that the joist
used is the one specified. If however you're looking at building up a
single joist where all the others are correct, and it doesn't have a
key role to play for some other reason, it may be ok.

"mmzz" wrote in message
ps.com...
does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?
What if the 2x2 was at right angles to the 4x2?



you mean 2x2 on top of a 4x2 ?

--
Vass
'02 YZF-R1

mmzz wrote:
does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?

No, except in size.

What if the 2x2 was at right angles to the 4x2?

I've no idea what you are talking about? - do you mean to cross batten it
with 2X2's?

yes
Vass wrote:
"mmzz" wrote in message
ps.com...
does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?
What if the 2x2 was at right angles to the 4x2?



you mean 2x2 on top of a 4x2 ?

--
Vass
'02 YZF-R1

mmzz wrote:

does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?

Assuming you mean 2x2 + 4x2 then if it were perfectly fixed, yes. In
practice glue and screw every 6" gets you closeish to this.


What if the 2x2 was at right angles to the 4x2?

no, not even close.


NT

"mmzz" wrote in message
ps.com...
does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?
What if the 2x2 was at right angles to the 4x2?


Unless the connection is designed to adequately transfer the shear through
the joint then no.

As a guide, if you were to put 2 3x2s on top of each other this would be
half as strong as a 6x2 and 4 times bendier.

Darryl Bailie wrote:
"mmzz" wrote in message
ps.com...

does glueing and screwing a length of 2x2 on top of a 6x2 joist make
the equivelant of a 6x2?
What if the 2x2 was at right angles to the 4x2?

Unless the connection is designed to adequately transfer the shear through
the joint then no.

in normal household use, glue and screw does do this. If you pushed the
wood right to its limit it might not, but that does not occur under any
normal household circumstances.


As a guide, if you were to put 2 3x2s on top of each other this would be
half as strong as a 6x2 and 4 times bendier.

if they werent connected, yes. But I think the idea is that they are.


NT