Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't know
where to start!

Can anyone offer any help or advice?

Thanks

Andrew

Andrew Barnes wrote:

Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't know
where to start!

Can anyone offer any help or advice?

Aye - Tony Bryer will be along in a while, but until he's here I'll plug
his allegedly excellent SuperBeam program, which you can get a
fully-functional print-disabled version of at

http://www.sda.co.uk/sbwdemo.htm

More design factors than you'd ever considered ;-) For such a relatively
tiny gap, you'll prolly find a simple off-the-shelf part at your local
Jewsons which is more than adequate. But that's just me handwaving...

"Andrew Barnes" wrote in message
...
Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't
know
where to start!

Can anyone offer any help or advice?

Thanks

Andrew

Use a wooden "I" beam, not over engineered steel.

See:
http://www.masonite-beams.se

They will do the calcs for you.

Andrew Barnes wrote:

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

Knowing what load is going to be supported by said beam would be one of
your prerequisites.

Is this a load bearing wall? What is is made out of?



--
Cheers,

John.

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

Knowing what load is going to be supported by said beam would be one of
your prerequisites.

Is this a load bearing wall? What is is made out of?


It is a solid brick wall (single thickness) supporting a similarly sized
wall above. The joists upstairs run parallel to it, as do those in the loft,
so I assume there is no load from the floors on it?

The wall is between my kitchen and dining room, I wish to make a
kitchen-diner.

The calcs need to satisfy a building officer!

Thanks

Andrew

In article ,
Andrew Barnes wrote:
It is a solid brick wall (single thickness) supporting a similarly sized
wall above. The joists upstairs run parallel to it, as do those in the
loft, so I assume there is no load from the floors on it?

The wall is between my kitchen and dining room, I wish to make a
kitchen-diner.

I'm willing to bet anything you can buy of that length (2m) will be fine.

The calcs need to satisfy a building officer!

But my bet won't. ;-)

--
*Real women don't have hot flashes, they have power surges.

Dave Plowman London SW
To e-mail, change noise into sound.

"Andrew Barnes" wrote in message
...
Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't
know
where to start!

Can anyone offer any help or advice?

Thanks

Andrew



There are various examples to be found by a quick Google. Try BS 5950

But a good general building reference book, which has some basic worked
examples is The Building Construction Handbook, by Chudley and Greeno. Its
about £15 and well worth it

First you need to know the load that a beam of a given section can carry,
then work out the load that it will be supporting. Once you have the
formula, steel section tables are available from Corus, and another Google
on ' weights of building materials ' will get you the info to work out the
loading.

I don't know if the Superbeam program already mentioned is available as a
trial. But its the lazy option if you want it !

dg

"Andrew Barnes" wrote in message
...
Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't
know
where to start!

Can anyone offer any help or advice?


This is just an anecdote relating to the above and is not meant to be smart:
I heard of an engineer whose first job was for the Irish Telephone company
in the early 1980s and his first assignment was to put a generator up on a
"beam". He got the weight of the generator and calculated load factors and
stuff
by looking up some big tables for different materials and doing some
calculations. Then he went to put the beam up. When he tried to find beams
of certains sizes and/or materials, his choice was severely limited.
In the end he used the biggest beam he could find.
I suspect you will end up doing something similar (or biggest beam that is
cheap and manageable)?

Des


Thanks

Andrew

"dg" wrote in message
k...
"Andrew Barnes" wrote in message
...
Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't
know
where to start!

Can anyone offer any help or advice?

Thanks

Andrew



There are various examples to be found by a quick Google. Try BS 5950

But a good general building reference book, which has some basic worked
examples is The Building Construction Handbook, by Chudley and Greeno. Its
about £15 and well worth it

First you need to know the load that a beam of a given section can carry,
then work out the load that it will be supporting. Once you have the
formula, steel section tables are available from Corus, and another Google
on ' weights of building materials ' will get you the info to work out the
loading.

Steel? get real a TJI "I" beam will do for most instances.

Andrew Barnes wrote:

Knowing what load is going to be supported by said beam would be one of
your prerequisites.

Is this a load bearing wall? What is is made out of?



It is a solid brick wall (single thickness) supporting a similarly sized
wall above. The joists upstairs run parallel to it, as do those in the loft,
so I assume there is no load from the floors on it?

The wall is between my kitchen and dining room, I wish to make a
kitchen-diner.

The calcs need to satisfy a building officer!

In that case just get a structural engineering firm to do the calcs.
They will be believed by the BCO and have professional indemnity
insurance if it falls down.


Thanks

Andrew

Des Higgins wrote:

"Andrew Barnes" wrote in message
...

Hi There

As a strict DIYer i would like to calculate the size of beam required to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't

know

where to start!

Can anyone offer any help or advice?



This is just an anecdote relating to the above and is not meant to be smart:
I heard of an engineer whose first job was for the Irish Telephone company
in the early 1980s and his first assignment was to put a generator up on a
"beam". He got the weight of the generator and calculated load factors and
stuff
by looking up some big tables for different materials and doing some
calculations. Then he went to put the beam up. When he tried to find beams
of certains sizes and/or materials, his choice was severely limited.
In the end he used the biggest beam he could find.
I suspect you will end up doing something similar (or biggest beam that is
cheap and manageable)?

Indeed.

In the end, 'big enough' is all it has to be.
'Too big' is when it won't fit...

The steel cost is not huge.

Just get an I beam that comfortably fits in, and use that.
I'd say a 6x3 I beam is more than man enough.



Des



Thanks

Andrew

"IMM" wrote in message
...

"dg" wrote in message
k...
"Andrew Barnes" wrote in message
...
Hi There

As a strict DIYer i would like to calculate the size of beam required
to
support a wall, when I make a 2m wide opening in a wall.

I am an engineer, but have been working in science for years, so don't
know
where to start!

Can anyone offer any help or advice?

Thanks

Andrew



There are various examples to be found by a quick Google. Try BS 5950

But a good general building reference book, which has some basic worked
examples is The Building Construction Handbook, by Chudley and Greeno.
Its
about £15 and well worth it

First you need to know the load that a beam of a given section can
carry,
then work out the load that it will be supporting. Once you have the
formula, steel section tables are available from Corus, and another
Google
on ' weights of building materials ' will get you the info to work out
the
loading.

Steel? get real a TJI "I" beam will do for most instances.


In the real world, price is always a consideration. Not sure what the price
of a 2m Trus Joist is, but a 14' 6"x4" steel beam cost me £35 about 2 years
ago.

Cheers
Clive

In article ,
Des Higgins wrote:
I suspect you will end up doing something similar (or biggest beam that
is cheap and manageable)?

I removed a stud but load bearing wall between kitchen and scullery. About
4 metres wide. BO was involved because of other works, and wanted
calculations. Which I got. Smallest RSJ was fine, not surprisingly.

--
*You are validating my inherent mistrust of strangers

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Imm wrote:
Use a wooden "I" beam, not over engineered steel.

See:
http://www.masonite-beams.se

I quite agree on not using an over-engineered steel. But, by
definition, the correctly chosen section in any particular location
will not be over-engineered. I suspect that the OP will find that a
127 x 76 UB, 13kg/m is quite adequate but would advise him to get
the calcs to confirm this from someone who is qualified (small 'q')
to do so. As to using a wooden I-beam I could not find any span/load
tables on the above site but generally would not advocate supporting
masonry walls off timber, even though this was done in past times.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

"Tony Bryer" wrote in message
...
In article , Imm wrote:
Use a wooden "I" beam, not over engineered steel.

See:
http://www.masonite-beams.se

I quite agree on not using an over-engineered steel. But, by
definition, the correctly chosen section in any particular location
will not be over-engineered. I suspect that the OP will find that a
127 x 76 UB, 13kg/m is quite adequate but would advise him to get
the calcs to confirm this from someone who is qualified (small 'q')
to do so. As to using a wooden I-beam I could not find any span/load
tables on the above site but generally would not advocate supporting
masonry walls off timber, even though this was done in past times.

In the USA it is common to support brick walls with TJIs.

Des Higgins wrote:


I suspect you will end up doing something similar (or biggest beam that is
cheap and manageable)?

To be fair, some of the steel fabricators are very flexible these days.
You can order pretty much exactly what you need.

--
Cheers,

John.

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

In article , Imm wrote:
In the USA it is common to support brick walls with TJIs.

It's a fundamentally unsound idea. TJI beams have got next to no
lateral stability. This is not a problem with floors because the
diaphragm effect of the floor deck keeps them straight and upright.
If you put a beam under a wall where does the lateral support come
from? In addition the OP wants to take out a wall at ground floor
level and support the wall over with a beam taking ? 2-3 tons which
means that at either end there will be an upward reaction of one ton
or more on the bottom flange of the beam. There's no way any
checking engineer would let you do this on a ply web beam without
designed stiffeners.

If you can direct us to some span/load tables we might just see what
would be needed.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

"Tony Bryer" wrote in message
...

but generally would not advocate supporting
masonry walls off timber, even though this was done in past times.


Why on earth not ? In most old houses it is the stone lintels that fail,
not the wooden ones. The only time wooden ones fail is when there is an
unfixed source of damp causing decay. Our house has bits up to 400 years
old and a good mixture of oak, stone and modern lintels in the extension,
and I bet I know which bits will still be intact in another couple of
hundred years.

"G&M" wrote in message
...

"Tony Bryer" wrote in message
...

but generally would not advocate supporting
masonry walls off timber, even though this was done in past times.


Why on earth not ? In most old houses it is the stone lintels that fail,
not the wooden ones. The only time wooden ones fail is when there is an
unfixed source of damp causing decay. Our house has bits up to 400 years
old and a good mixture of oak, stone and modern lintels in the extension,
and I bet I know which bits will still be intact in another couple of
hundred years.




Well the main problem is progressive and seasonal movement, which may not
only play havoc with the decorations of a modern house, but may not be
suitable to other materials in the structure which don't cope to well with
such movement.

dg

"John Rumm" wrote in message
...
Des Higgins wrote:


I suspect you will end up doing something similar (or biggest beam that
is
cheap and manageable)?

To be fair, some of the steel fabricators are very flexible these days.
You can order pretty much exactly what you need.

--
Cheers,

John.


Our local steel suppliers will do the calcs, and select a suitable beam for
you if you ask nicely

dg

"Tony Bryer" wrote in message
...
In article , Imm wrote:
In the USA it is common to support brick walls with TJIs.

It's a fundamentally unsound idea. TJI beams have got next to no
lateral stability. This is not a problem with floors because the
diaphragm effect of the floor deck keeps them straight and upright.
If you put a beam under a wall where does the lateral support come
from? In addition the OP wants to take out a wall at ground floor
level and support the wall over with a beam taking ? 2-3 tons which
means that at either end there will be an upward reaction of one ton
or more on the bottom flange of the beam. There's no way any
checking engineer would let you do this on a ply web beam without
designed stiffeners.

If you can direct us to some span/load tables we might just see what
would be needed.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm



Although I agree that use of such a beam is a bad idea, it is interesting to
note the many houses built up to the mid 60's with first floor walls built
off a single or doubled timber joist.

Walls built off timber from new would settle naturally, but its a different
matter when retrospectively fitting a timber support in situations like
this.

dg

I had some advice from the group recently on getting a beam. The
structural engineers I contacted wouldn't get out of bed for less than
=A3250!

I downloaded the SDA product. which worked a treat to calculate the
beam I needed.

Tim


dg wrote:
"Tony Bryer" wrote in message
...
In article , Imm wrote:
In the USA it is common to support brick walls with TJIs.

It's a fundamentally unsound idea. TJI beams have got next to no
lateral stability. This is not a problem with floors because the
diaphragm effect of the floor deck keeps them straight and upright.
If you put a beam under a wall where does the lateral support come
from? In addition the OP wants to take out a wall at ground floor
level and support the wall over with a beam taking ? 2-3 tons which
means that at either end there will be an upward reaction of one
ton
or more on the bottom flange of the beam. There's no way any
checking engineer would let you do this on a ply web beam without
designed stiffeners.

If you can direct us to some span/load tables we might just see
what
would be needed.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm



Although I agree that use of such a beam is a bad idea, it is
interesting to
note the many houses built up to the mid 60's with first floor walls
built
off a single or doubled timber joist.

Walls built off timber from new would settle naturally, but its a
different
matter when retrospectively fitting a timber support in situations
like
this.
=20
dg

"dg" wrote in message
.. .
"G&M" wrote in message
...

"Tony Bryer" wrote in message
...

but generally would not advocate supporting
masonry walls off timber, even though this was done in past times.


Why on earth not ? In most old houses it is the stone lintels that
fail,
not the wooden ones. The only time wooden ones fail is when there is an
unfixed source of damp causing decay. Our house has bits up to 400
years
old and a good mixture of oak, stone and modern lintels in the
extension,
and I bet I know which bits will still be intact in another couple of
hundred years.




Well the main problem is progressive and seasonal movement, which may not
only play havoc with the decorations of a modern house, but may not be
suitable to other materials in the structure which don't cope to well with
such movement.


Use lime mortar (as Grand Designs did tonight) and such problems go away.

In article , Dg wrote:
Although I agree that use of such a beam is a bad idea, it is
interesting to note the many houses built up to the mid 60's with
first floor walls built off a single or doubled timber joist.

Yes, but double joists nailed together have a lot of lateral
stiffness when compared with one of IMM's TJI beams which are
basically 50x50 top and bottom with a ply web.


Walls built off timber from new would settle naturally, but its a
different matter when retrospectively fitting a timber support in
situations like this.

Quite so: on site you'd put the beam in and build the wall up -
probably in lime mortar - and as the beam deflected under the weight
the mortar would accommodate this. If you put a beam under an
existing wall you need to properly preload it or there is a risk that
over a period the weight will gradually shift to the beam causing
cracking. This would be far more likely with timber which (a)
deflects more - deflection is usually what governs timber member
sizing; and (b) creeps: put x tons on a steel beam and it deflects by
y .. and never moves any further; put x on a timber and next
week/month you'll find that the deflection is more than it is now.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

"Tony Bryer" wrote in message
...
In article , Dg wrote:
Although I agree that use of such a beam is a bad idea, it is
interesting to note the many houses built up to the mid 60's with
first floor walls built off a single or doubled timber joist.

Yes, but double joists nailed together have a lot of lateral
stiffness when compared with one of IMM's TJI beams which are
basically 50x50 top and bottom with a ply web.


Ahhh no ... there is no ply web, it is akin to 14mm OSB, but not ply.

They are also 90mm wide for typical domestic beams not 50mm, and 300mm deep.

It is unfair to compare the stiffness of one TJI beam against a joist, TJI
beams are designed with a complete homogenous floor system ... i.e. Silent
Floor
Where the Intralam ring beam and the glued & fixed deck all contribute to
the finished performance not one individual beam.


Rick

In article , Rick Hughes
wrote:
It is unfair to compare the stiffness of one TJI beam against a
joist, TJI beams are designed with a complete homogenous floor
system ... i.e. Silent Floor

And I have absolutely no problem with them being used for such. I
am totally unconvinced that a single TJI is a suitable substitute
for a steel beam supporting a masonry wall over.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
http://www.sda.co.uk/qsedbuk.htm

Tony Bryer wrote:

It is unfair to compare the stiffness of one TJI beam against a
joist, TJI beams are designed with a complete homogenous floor
system ... i.e. Silent Floor


And I have absolutely no problem with them being used for such. I
am totally unconvinced that a single TJI is a suitable substitute
for a steel beam supporting a masonry wall over.

Given that they are likely to be deeper than a standard joist (let alone
SHS steel), have less lateral stability, and no doubt cost more, it
seems hard to see the advantage in most domestic house construction
projects. Which does make you wonder why some fool keeps sugesting them!

--
Cheers,

John.

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

On Wed, 15 Sep 2004 08:10:59 +0100, a particular chimpanzee named
"Andrew Barnes" randomly hit the
keyboard and produced:

The calcs need to satisfy a building officer!

Are you sure? Has he asked you for calculations, or just to let him
know what beam you intend to put in? IME, for a 2m opening, if you
were to specify a reasonably-sized beam (i.e., a 178 x 102 UB) then
it's unlikely that the BCO wouldn't accept this without calculations.

If necessary you could try a box lintel from Catnic, who I understand
will provide calculations for you.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'

On Sun, 19 Sep 2004 00:13:45 +0100, a particular chimpanzee named Tony
Bryer randomly hit the keyboard and produced:
snip everything
IMM's managed to do what he does best; come up with an unworkable,
stupid idea, and get the rest of us to argue amongst ourselves as to
exactly why it's unworkable and stupid.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'

"Hugo Nebula" abuse@localhost wrote in message
...
On Wed, 15 Sep 2004 08:10:59 +0100, a particular chimpanzee named
"Andrew Barnes" randomly hit the
keyboard and produced:

The calcs need to satisfy a building officer!

Are you sure? Has he asked you for calculations, or just to let him
know what beam you intend to put in? IME, for a 2m opening, if you
were to specify a reasonably-sized beam (i.e., a 178 x 102 UB) then
it's unlikely that the BCO wouldn't accept this without calculations.

Mine wanted calculations for a 80 cm opening over a doorway (2 standard
100*65 lintels)

On Fri, 24 Sep 2004 21:24:59 +0100, a particular chimpanzee named
"G&M" randomly hit the keyboard and
produced:

Mine wanted calculations for a 80 cm opening over a doorway (2 standard
100*65 lintels)

With point loads on them or less than three courses of masonry over
them, perhaps? Pre-stressed lintels require the composite effect of
the masonry over them to work satisfactorily. Perhaps asking for
calcs was a way of proving to someone who argues every point that they
won't work.

Or maybe you've just ****ed him off something rotten.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'

"Hugo Nebula" abuse@localhost wrote in message
...
On Fri, 24 Sep 2004 21:24:59 +0100, a particular chimpanzee named
"G&M" randomly hit the keyboard and
produced:

Mine wanted calculations for a 80 cm opening over a doorway (2 standard
100*65 lintels)

With point loads on them or less than three courses of masonry over
them, perhaps? Pre-stressed lintels require the composite effect of
the masonry over them to work satisfactorily.

There were two courses then the upstairs floor joists. I phoned the lintel
manufacturer up for their figures and they offered to do the calcs for me
for free. Which they did and it passed easily.



Or maybe you've just ****ed him off something rotten.

If refusing to submit full plans counts then yes I've ****ed him off
something rotten. I always use a building notice as it allows more
flexibility as you take apart an old building and need to modify things.

"Hugo Nebula" abuse@localhost wrote in message
...
On Fri, 24 Sep 2004 21:24:59 +0100, a particular chimpanzee named
"G&M" randomly hit the keyboard and
produced:

Mine wanted calculations for a 80 cm opening over a doorway (2 standard
100*65 lintels)

With point loads on them or less than three courses of masonry over
them, perhaps? Pre-stressed lintels require the composite effect of
the masonry over them to work satisfactorily.

Just thought about this again. You are talking crap of IMM proportions.
All pre-stressed lintels have a point loading specification so no brick
courses are mandatory. Indeed it is quite common to place joists directly
on them.

Also if you have more than three courses of brick above a 80cm opening all
loads above and outside the triangle are taken by the side walls so the only
loading on the lintel is a few bricks.

I have been presuming you were a real live BCO but if that is the case I
would have expected you to have a much better understanding of loading
calculations.

On Mon, 27 Sep 2004 22:50:15 +0100, a particular chimpanzee named
"G&M" randomly hit the keyboard and
produced:

All pre-stressed lintels have a point loading specification so no brick
courses are mandatory. Indeed it is quite common to place joists directly
on them.

A prestressed lintel _can_ be composite or non-composite. Composite
lintels need the action of three courses of brickwork (or two of
blockwork). These are usually the 65mm deep ones. Non-composite
don't need the masonry above, and come in depths of 100mm or more.
Yours are, therefore, composite ones.

You are talking crap of IMM proportions.

I have been presuming you were a real live BCO but if that is the case I
would have expected you to have a much better understanding of loading
calculations.

I would run with the ****ing people off angle; you're doing a damn
fine job at it with me.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'

"Hugo Nebula" abuse@localhost wrote in message
...

A prestressed lintel _can_ be composite or non-composite. Composite
lintels need the action of three courses of brickwork (or two of
blockwork). These are usually the 65mm deep ones. Non-composite
don't need the masonry above, and come in depths of 100mm or more.
Yours are, therefore, composite ones.

Nope - mine is the Naylor P100 which I believe are non-composite. However I
will check this with them tomorrow just to make sure.



I would run with the ****ing people off angle; you're doing a damn fine
job at it with me.
Hugo Nebula

You're the person calling everybody chimpanzees !

G&M wrote:

Also if you have more than three courses of brick above a 80cm
opening all loads above and outside the triangle are taken by the
side walls so the only loading on the lintel is a few bricks.

I think that's crap of IMM proportions from yourself, actually. I've
got in front of me the BRE's 'Good Building Guide' no. 10 (dated
November '91 - so probably not the latest version). This gives
simplified methods for estimating loadings where temporary openings are
to be made.

The BRE publication defines two triangles, both with a base 10% wider
than the clear span of the opening - 880 mm in this case. The load
triangle has base angles of 45 deg. and the weight of the masonry plus
any point loads supported within this triangle are considered to be
supported 100% by the lintel. The height of this triangle is clearly
equal to half its base, so extends up to 440 mm above the opening -
that's nearly 6 courses of brick, not 3.

Then there is the interaction triangle, which has 60 deg. base angles
and the apex at half the base times sqrt(3) - 762 mm. 50% of any loads
placed within the interaction zone, being the area that's inside the
interaction triangle but not the load triangle, are considered to be
supported by the lintel.

Thus only loads higher than 10-and-a-bit courses above the lintel can be
safely ignored without resorting to more precise calculation methods.
That's not quite what you said above.

I have been presuming you were a real live BCO but if that is the case I
would have expected you to have a much better understanding of loading
calculations.

Hmmm...

--
Andy

"Andy Wade" wrote in message
...
G&M wrote:

Also if you have more than three courses of brick above a 80cm
opening all loads above and outside the triangle are taken by the
side walls so the only loading on the lintel is a few bricks.

I think that's crap of IMM proportions from yourself, actually. I've
got in front of me the BRE's 'Good Building Guide' no. 10 (dated
November '91 - so probably not the latest version). This gives
simplified methods for estimating loadings where temporary openings are
to be made.

Sorry - I accept I made a typo there as I was thinking about blocks which I
was using that day but typed bricks. However the original point still
stands that good lintels don't need these layers for strength purposes.

"G&M" wrote in message
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"Hugo Nebula" abuse@localhost wrote in message
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A prestressed lintel _can_ be composite or non-composite. Composite
lintels need the action of three courses of brickwork (or two of
blockwork). These are usually the 65mm deep ones. Non-composite
don't need the masonry above, and come in depths of 100mm or more.
Yours are, therefore, composite ones.

Nope - mine is the Naylor P100 which I believe are non-composite. However
I
will check this with them tomorrow just to make sure.

Checked and can confirm all Naylor lintels are non-composite and do not need
three layers of brick or any other method to give them their quoted
strength. Joists or other point loads can be lain directly on them within
the loads given in the tables on their website.