Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

David

In theory you should dry pack if you do not build the bricks onto the
lintel. To dry pack you leave a thin gap above the lintel and wedge in the
gap slate to pin the bricks up. You then push/spread as much mortar into the
gaps left. It wont go anywhere

"Lobster" wrote in message
om...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

David

Leaving a gap between the lintel and the masonry will mean the bricks are
not supported properly and will drop onto the lintel. Dropping bricks, even
by a slight amount, is not what you want. The lintel is put there to hold
the bricks in one place so should actually be resting on the lintel with
nothing between them. To tidy up the edge you can point some mortar along
it, but this shouldn't be necessary if the lintel is being boxed in
correctly.

"BigWallop" wrote in message ...
"Lobster" wrote in message
om...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

Leaving a gap between the lintel and the masonry will mean the bricks are
not supported properly and will drop onto the lintel. Dropping bricks, even
by a slight amount, is not what you want. The lintel is put there to hold
the bricks in one place so should actually be resting on the lintel with
nothing between them. To tidy up the edge you can point some mortar along
it, but this shouldn't be necessary if the lintel is being boxed in
correctly.

Thanks (and to Mike). So basically, when the lintel slot is cut, you
should be aiming for as tight a vertical fit as possible, and if there
is a gap, pack with slate? I hadn't realised that mortar in the gap
above the lintel is not intended to be loadbearing.

By the way, has anybody used these 'Jackall' props, available from
HSS?
(see http://tinyurl.com/274ya)
Are they easy/safe to use, as an alternative to conventional
needles/acro props? I'm not entirely clear how they work, looking at
the picture.

Cheers
David

In article ,
BigWallop wrote:
Leaving a gap between the lintel and the masonry will mean the
bricks are not supported properly and will drop onto the lintel.
Dropping bricks, even by a slight amount, is not what you want.
The lintel is put there to hold the bricks in one place so
should actually be resting on the lintel with nothing between
them.

I'd prefer to see a gap of 15-25mm between the top of the lintel
and wall over which is then dry-packed: 1:1 cement and sand with
just enough water to hold it together when you squeeze it. This
needs to be rammed into the gap with a suitable piece of wood and
hammer.

--
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 ,
BigWallop wrote:
Leaving a gap between the lintel and the masonry will mean the
bricks are not supported properly and will drop onto the lintel.
Dropping bricks, even by a slight amount, is not what you want.
The lintel is put there to hold the bricks in one place so
should actually be resting on the lintel with nothing between
them.

I'd prefer to see a gap of 15-25mm between the top of the lintel
and wall over which is then dry-packed: 1:1 cement and sand with
just enough water to hold it together when you squeeze it. This
needs to be rammed into the gap with a suitable piece of wood and
hammer.


And if the mortar crumbles ? Down comes the lot above it. No Thanks.


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"BigWallop" wrote in message
...

"Tony Bryer" wrote in message
...
In article ,
BigWallop wrote:
Leaving a gap between the lintel and the masonry will mean the
bricks are not supported properly and will drop onto the lintel.
Dropping bricks, even by a slight amount, is not what you want.
The lintel is put there to hold the bricks in one place so
should actually be resting on the lintel with nothing between
them.

I'd prefer to see a gap of 15-25mm between the top of the lintel
and wall over which is then dry-packed: 1:1 cement and sand with
just enough water to hold it together when you squeeze it. This
needs to be rammed into the gap with a suitable piece of wood and
hammer.


And if the mortar crumbles ? Down comes the lot above it. No Thanks.

BW, dry packing as Tony describes really is the proper way to do things. Any
structural engineer would recommend it. It is also the method used for packing
between old foundations and new underpinning. The big benefit is it that the
mortar moulds itself to the bottom surface of the brickwork above, giving a
solid overall bearing, rather than bearing on just a few high spots.

The mix has to be strong (I would say 1 cement to 2 sharp sand by volume), and
fairly dry - just wet enough to give proper hydration of the cement. This would
form a cohesive ball in your hand if you squeezed it. And you must kill any
suction from the brickwork by wetting it first. The props should be left in
position for at least 3 days, a week is better. If you have experienced
crumbling mortar then something was obviously wrong.

Peter

In article ,
BigWallop wrote:
And if the mortar crumbles ? Down comes the lot above it.
No Thanks.

That's the point: we are *not* talking mortar. Drypacking uses
*sharp* sand and cement, just enough water so that when you
squeeze a ball in your hand it holds together but no excess water
comes out. After a week it's like rock. It's what they ram in
between column base plates and foundation bases on steel
buildings.

--
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

(Lobster) wrote in message . com...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons


I had a similar problem a few years ago. My brother (who claims to be
an engineer) recommended against the use of cement based mortar, on
the basis that even if packed well into the gap, the mortar will
shrink. He recommended shrink proof grout - it is similar to cement
but no sand is added, and it is forced into the gap in the same way as
mortar. I sourced a bag in a specialist cement manufacturer. Cannot
remember the name but as I am in Ireland so it would be of no use to
you.

I cannot remember the correct terminology but a search on Google gave
the following http://www.acml.co.uk/cx1.htm. It might be worth a
call

On 20 Jan 2004 12:15:59 -0800, Lobster wrote:

If you are fitting a lintel over an opening, to support several tons
of masonry above,

Erm, it's not. It's really only supporting the triangle of bricks
directly above it. It will have some of the load of the full wall but
not as much as one might expect. You can take out the triangle of
bricks above an opening and the wall won't collapse, unless the
redistributed load to the sides of the opening becomes to great for
those bricks to carry. It might not be "safe" though...

--
Cheers
Dave. pam is missing e-mail

"Lobster" wrote in message
om...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

David

Well I've learned a lot from this thread. I'm glad I came in with my two
pennith now, because it shows what knowledge you can get when you disagree
with people a little. I just hope you have all your answers now David ?
:-))

"BigWallop" wrote in message ...
"Lobster" wrote in message
om...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

Well I've learned a lot from this thread. I'm glad I came in with my two
pennith now, because it shows what knowledge you can get when you disagree
with people a little. I just hope you have all your answers now David ?
:-))

Yep, looks like I'm all set now. Glad I didn't rush off and do the
job after reading the just first two replies!! :-) Many thanks to
all.

Anyone care to comment on my follow-up about these new 'Jackall'
props?
(http://tinyurl.com/274ya)

David

"Lobster" wrote in message
om...
"BigWallop" wrote in message
...
"Lobster" wrote in message
om...
Probably a daft question but what the hell...

If you are fitting a lintel over an opening, to support several tons
of masonry above, how do you get an adequate amount of mortar into the
(hopefully small) gap above the lintel and below the bricks it's
supporting? Do you have to just force the stuff in with a trowel and
hope you don't have any airgaps inside? Presumably if there is
insufficient set mortar in there, at best you run the risk of the wall
"settling" once the acros are removed... what's the secret?

Well I've learned a lot from this thread. I'm glad I came in with my
two
pennith now, because it shows what knowledge you can get when you
disagree
with people a little. I just hope you have all your answers now David ?
:-))

Yep, looks like I'm all set now. Glad I didn't rush off and do the
job after reading the just first two replies!! :-) Many thanks to
all.

Anyone care to comment on my follow-up about these new 'Jackall'
props?
(http://tinyurl.com/274ya)

David

The tinyurl link won't work for me, but if you mean these:

http://www.dborc.demon.co.uk/cache/15961.jpg

then they are OK for small jobs that only require holding for a short space
of time. Best to get solid props if you have to leave them in place for a
long while without movement.


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On Wed, 21 Jan 2004 23:23:45 +0000 (GMT), "Dave Liquorice"
wrote:

Erm, it's not. It's really only supporting the triangle of bricks
directly above it. It will have some of the load of the full wall but
not as much as one might expect. You can take out the triangle of
bricks above an opening and the wall won't collapse, unless the
redistributed load to the sides of the opening becomes to great for
those bricks to carry. It might not be "safe" though...

So as a matter of curiosity, what sort of weight are we talking about
on a load-bearing wall? I have always assumed it must be measured in
tons, but I've never seen any figures.

PoP

Sending email to my published email address isn't
guaranteed to reach me.

"BigWallop" wrote in message ...

"Lobster" wrote in message
om...

Anyone care to comment on my follow-up about these new 'Jackall'
props?
(http://tinyurl.com/274ya)

The tinyurl link won't work for me, but if you mean these:

http://www.dborc.demon.co.uk/cache/15961.jpg

then they are OK for small jobs that only require holding for a short space
of time. Best to get solid props if you have to leave them in place for a
long while without movement.

Funny, the tinyurl still works OK here. The HSS link is actually
http://www.hss.com/Fae.asp?syspage=w...ysclearSQL=YES
.....so you can see why I went for a tinyurl link! Doesn't look the
same as the ones in the jpg you indicated; but I don't know how those
work either!

David

In article ,
Lobster writes
"BigWallop" wrote in message news:1VLPb.6
...

"Lobster" wrote in message
om...

Anyone care to comment on my follow-up about these new 'Jackall'
props?
(http://tinyurl.com/274ya)

The tinyurl link won't work for me, but if you mean these:

http://www.dborc.demon.co.uk/cache/15961.jpg

then they are OK for small jobs that only require holding for a short space
of time. Best to get solid props if you have to leave them in place for a
long while without movement.

Funny, the tinyurl still works OK here. The HSS link is actually
http://www.hss.com/Fae.asp?syspage=w...sion=HIRE& Ca
tegory=BUISUPPORT&sysclearSQL=YES
....so you can see why I went for a tinyurl link! Doesn't look the
same as the ones in the jpg you indicated; but I don't know how those
work either!

David

I get:
"LoadPageLanguage - Error -2147217865: [Microsoft][ODBC SQL Server
Driver][SQL Server]Invalid object name 'Pages_'. LoadPageButtons - Error
3709: The connection cannot be used to perform this operation. It is either
closed or invalid in this context."
Are you getting it from your cache?
--
fred

fred wrote:
I get:
"LoadPageLanguage - Error -2147217865: [Microsoft][ODBC SQL Server
Driver][SQL Server]Invalid object name 'Pages_'. LoadPageButtons -

Snap.
I think the HSS Jackall props are the C shaped fair where you knock a hole
above and below the lintel, stick in the support and wind it out, very good
for a long way up an outside wall. The standard acrow props are a lot less
to hire, and should be available from the local friendly independent hire
shop.
Alternatively second hand at ~£10 each.

--
Toby.

'One day son, all this will be finished'

"Toby" wrote in message
...
fred wrote:
I get:
"LoadPageLanguage - Error -2147217865: [Microsoft][ODBC SQL Server
Driver][SQL Server]Invalid object name 'Pages_'. LoadPageButtons -

Snap.
I think the HSS Jackall props are the C shaped fair where you knock a hole
above and below the lintel, stick in the support and wind it out, very good
for a long way up an outside wall. The standard acrow props are a lot less
to hire, and should be available from the local friendly independent hire
shop.
Alternatively second hand at ~£10 each.

--
Toby.


The link works OK for me (weird or what???) although the picture shows a few
Strongboy heads on ordinary Acrows, not Jackalls. The hire price for the
Jackalls is £12.00 a day, ordinary props are £6.50 plus the Strongboy heads
£7.50, so Jackalls are cheaper than Strongboys at HSS.

Last year I had to sort out a building in London W2 where a builder had
supported two sides of a 3 storey rear addition on 6 Strongboys while he altered
the basement walls. Because the load is offset from the prop, the Strongboy
head creates a bending force on the prop, and these 6 had bowed like bananas.
As a result the rear addition had fractured and moved away from the main
building about 50mm at the top. We had to evacuate it and the BCO slapped a
dangerous structure notice on it. So it was a good reminder that Strongboys
aren't all *that* strong.

Peter

Peter Taylor wrote:
these 6 had bowed like bananas. As a result the rear addition had
fractured and moved away from the main building about 50mm at the
top. We had to evacuate it and the BCO slapped a dangerous structure

'kin ell. Any building that has people in it that has moved 2 inches already
seems highly likely to move a lot further rapidly downwards. I guess that
also means a fairly comprehensive rebuild.

--
Toby.

'One day son, all this will be finished'

"Toby" wrote in message
...
Peter Taylor wrote:
these 6 had bowed like bananas. As a result the rear addition had
fractured and moved away from the main building about 50mm at the
top. We had to evacuate it and the BCO slapped a dangerous structure

'kin ell. Any building that has people in it that has moved 2 inches
already
seems highly likely to move a lot further rapidly downwards. I guess that
also means a fairly comprehensive rebuild.


And wapping big insurance claim.

--
Toby.

'One day son, all this will be finished'




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The link works OK for me (weird or what???) although the picture shows a
few
Strongboy heads on ordinary Acrows, not Jackalls. The hire price for the
Jackalls is £12.00 a day, ordinary props are £6.50 plus the Strongboy
heads
£7.50, so Jackalls are cheaper than Strongboys at HSS.

Strongboys are usually £2.50 a week ! Find another hire place.