On 1 May, 09:12, Chris Holford
wrote:
I need to make a very strong fixing to a brick wall using expanding
bolts 90mm long.
I drilled 14mm dia holes in the brick.
After going into the brick about 30 t0 40mm, the drill broke through
into a cavity in the brick and then started to 'bite' about 30 to 40 mm
further in.

I suspect the bricks are the type with 3 large vertical holes.

Help!

( I have wondered about the following solution;

* * * * get a mastic gun and empty cartridge

* * * * fill it with wet cement and inject the cement into the brick via
* * * * the 14mm hole

* * * * hammer a 12mm wooden plug into the hole to consolidate the
* * * * cement in the void

* * * * drill out the wooden plug after the cement has set

Any comments on this idea? -or alternatives? The fixing will need to
take a large load.
Thanks

--
Chris Holford

Is the load in sheer or straight pull?
I build a mezzanine in the roof of a garage using Mulitmonti bolts.
Theres a ton of stuff on it now.
Cross posted to uk.diy as thats probably a good place to get an answer
from

Dave

Rather than the uncertain repair that the OP proposes, I would suggest
simply filling the original drillings and starting again *with a much
longer fixing*.

Is this a single leaf of masonry, or is there an inner leaf? Is the
outer leaf possibly not intended to take extra structural loads?

I'd also recommend multimonti - I think some very long ones are
available now.

IIRC the data sheet with multimonti covers all common load
configurations. I used multimonti (10*140mm), 4 to a joist hanger to
support an upper floor in a chapel conversion (all inspected and
passed by building control). In that configuration the safety margin
from calculations was generous - however, like most building work,
quality of workmanship makes a huge difference. I made up a jig to
ensure that all pre-drillings were set as accurately as possible, and
every single bolt was totally secure (and I set a couple of test
multimonti, then tried (unsuccessfully) to lever them out with a very
long crowbar).

The OP doesn't say what his application is. Is it safety critical - a
roof, floor or structural component? If so, professional or very
experienced advice may be necessary, and/or building control
oversight.

Are there dynamic factors, wind or snow loading?

Where you're using fixings as critical structural component, I really
wouldn't do anything that isn't *certain*, and the repair method
proposed sounds far from certain.

Dave S coughed up some electrons that declared:

On 1 May, 09:12, Chris Holford
wrote:
I need to make a very strong fixing to a brick wall using expanding
bolts 90mm long.
I drilled 14mm dia holes in the brick.
After going into the brick about 30 t0 40mm, the drill broke through
into a cavity in the brick and then started to 'bite' about 30 to 40 mm
further in.

I suspect the bricks are the type with 3 large vertical holes.

Help!

( I have wondered about the following solution;

get a mastic gun and empty cartridge

fill it with wet cement and inject the cement into the brick via
the 14mm hole

hammer a 12mm wooden plug into the hole to consolidate the
cement in the void

drill out the wooden plug after the cement has set

Any comments on this idea? -or alternatives? The fixing will need to
take a large load.
Thanks

--
Chris Holford

Is the load in sheer or straight pull?
I build a mezzanine in the roof of a garage using Mulitmonti bolts.
Theres a ton of stuff on it now.
Cross posted to uk.diy as thats probably a good place to get an answer
from

Dave

Or switch to resin anchors? No doubt that they're strong enough and they
won't damage the brick near a cavity.

Cheers

Tim

In article , Tim S
writes
On 1 May, 09:12, Chris Holford
wrote:
I need to make a very strong fixing to a brick wall using expanding
bolts 90mm long.
I drilled 14mm dia holes in the brick.
After going into the brick about 30 t0 40mm, the drill broke through
into a cavity in the brick and then started to 'bite' about 30 to 40 mm
further in.

I suspect the bricks are the type with 3 large vertical holes.


Or switch to resin anchors? No doubt that they're strong enough and they
won't damage the brick near a cavity.

Prob best used with these to avoid using a cart of resin per hole,
pricey though:
http://www.screwfix.com/prods/36745 or
http://www.screwfix.com/prods/22991

Actually, if it's only a few holes, it would be cheaper to fill the void
(if it is only a 3 hole brick).
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

RubberBiker wrote:
Rather than the uncertain repair that the OP proposes, I would suggest
simply filling the original drillings and starting again *with a much
longer fixing*.

Is this a single leaf of masonry, or is there an inner leaf? Is the
outer leaf possibly not intended to take extra structural loads?

I'd also recommend multimonti - I think some very long ones are
available now.

Me too. Easier to pull a sailor off your sister than pull one out.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On 1 May, 16:16, "The Medway Handyman"
wrote:
RubberBiker wrote:
Rather than the uncertain repair that the OP proposes, I would suggest
simply filling the original drillings and starting again *with a much
longer fixing*.

Is this a single leaf of masonry, or is there an inner leaf? Is the
outer leaf possibly not intended to take extra structural loads?

I'd also recommend multimonti - I think some very long ones are
available now.

Me too. *Easier to pull a sailor off your sister than pull one out.

The only thing I wondered about multi-monti (I've not used them).
SInce they cut their own thread, the hole size must be quite critical
to the strength. With a slightly wobbly SDS, or slightly crumbly
brick, the hole could be a millimeter larger, which could make all the
difference ?
Simon.

I'd also recommend multimonti - I think some very long ones are
available now.


Are the multi-monti better than the bolt things which expand?

Do you just drill a pilot hole with a sds drill
then drive them in with an impact driver?

Do they unscrew, or is that that once they're in they're in?

[g]

On Fri, 01 May 2009 17:39:53 +0100, george (dicegeorge) wrote:



I'd also recommend multimonti - I think some very long ones are
available now.


Are the multi-monti better than the bolt things which expand?

Do you just drill a pilot hole with a sds drill then drive them in with an
impact driver?

Do they unscrew, or is that that once they're in they're in?

[g]

=========================================

Screwfix give a good description of their usage including drill size(s)
required:

http://www.screwfix.com/prods/45200/...50www.screwfix

http://tinyurl.com/chc8h5

Cic.
--
==========================================
Using Ubuntu Linux
Windows shown the door
==========================================

george (dicegeorge) wrote:

Are the multi-monti better than the bolt things which expand?

Much better in my opinion. They don't expand so they they don't damage
the bricks. They also need a much smaller hole.

Do you just drill a pilot hole with a sds drill

Yes.

then drive them in with an impact driver?

No, you just screw them in with a normal screw driver, nut driver or
spanner. They're very easy to drive home. They come with a choice of a
normal bolt head or a Torx head.

In general I would use a longer Multi-Monti than an expanding bolt to
ensure a good fix.

george (dicegeorge) wrote:
I'd also recommend multimonti - I think some very long ones are
available now.


Are the multi-monti better than the bolt things which expand?

Much less chance of a brick splitting & you can use them pretty close to
edges - although not 'right' up to an edge.

Do you just drill a pilot hole with a sds drill
then drive them in with an impact driver?

Yup. Decent drill driver will put them in, impact driver is obviously
faster.

Do they unscrew, or is that that once they're in they're in?

No, you can take them out & put them back no problem, or take them out &
resuse them.

Brilliant things. Somebody here put me on to them, can't recall who, but
thanks :-)


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

wrote:
On 1 May, 16:16, "The Medway Handyman"
wrote:
RubberBiker wrote:
Rather than the uncertain repair that the OP proposes, I would
suggest simply filling the original drillings and starting again
*with a much longer fixing*.

Is this a single leaf of masonry, or is there an inner leaf? Is the
outer leaf possibly not intended to take extra structural loads?

I'd also recommend multimonti - I think some very long ones are
available now.

Me too. Easier to pull a sailor off your sister than pull one out.

The only thing I wondered about multi-monti (I've not used them).
SInce they cut their own thread, the hole size must be quite critical
to the strength. With a slightly wobbly SDS, or slightly crumbly
brick, the hole could be a millimeter larger, which could make all the
difference ?

I guess it is, but in practise I've not really had any problems. I use the
6mm with a 5mm pilot & the 7.5mm with a 6mm pilot. You get the odd failure,
just like you would with any fixing, but overall they are brill.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

I notice they are carbon steel.

I assume sufficiently oversized w.r.t. corrosion over 40yrs, or is it
Build-Like-Barratt these days?

Then again get enough damp to eat a big screw away and even a tough
brick can be drilled with a screwdriver.


Anchor bolts are available in stainless, as are resin fastenings, the
problem with anchor bolts is they can be very fussy about hole size
and stainless needs oversizing being a relatively low grade. Still
most roofs are still standing held together with little more than a
big nail at an angle with more attention to the finger & cigarette
position than wood, nail & hammer.

Cicero wrote:
On Fri, 01 May 2009 17:39:53 +0100, george (dicegeorge) wrote:


I'd also recommend multimonti - I think some very long ones are
available now.

Are the multi-monti better than the bolt things which expand?

Do you just drill a pilot hole with a sds drill then drive them in with an
impact driver?

Do they unscrew, or is that that once they're in they're in?

[g]

=========================================

Screwfix give a good description of their usage including drill size(s)
required:

http://www.screwfix.com/prods/45200/...50www.screwfix

http://tinyurl.com/chc8h5

Cic.

I notice that the Screwfix blurb cites "reusable", but the technical
approval (sec. 4.2.2) specifically states "The anchor may be used only
once".

Also, it seems they are only suitable for static or quasi-static loads
and have a design life of only 50 years.

For the 10mm dia. bolt, the nominal hole size is 8mm with a maximum size
of 8.45mm. So yes, you need to be careful drilling the hole.

Compare this with a 10mm dia. shield anchor (Rawlbolt) where the nominal
hole size is 16mm and the maximum is (not stated by Rawl but) probably
in excess of 18mm, so a much bigger hole but much more leeway on the
hole size.

On Fri, 01 May 2009 19:29:48 +0100, Dave Osborne wrote:

Cicero wrote:
On Fri, 01 May 2009 17:39:53 +0100, george (dicegeorge) wrote:


I'd also recommend multimonti - I think some very long ones are
available now.

Are the multi-monti better than the bolt things which expand?

Do you just drill a pilot hole with a sds drill then drive them in with
an impact driver?

Do they unscrew, or is that that once they're in they're in?

[g]

=========================================

Screwfix give a good description of their usage including drill size(s)
required:

http://www.screwfix.com/prods/45200/...50www.screwfix

http://tinyurl.com/chc8h5

Cic.

I notice that the Screwfix blurb cites "reusable", but the technical
approval (sec. 4.2.2) specifically states "The anchor may be used only
once".

Also, it seems they are only suitable for static or quasi-static loads and
have a design life of only 50 years.

For the 10mm dia. bolt, the nominal hole size is 8mm with a maximum size
of 8.45mm. So yes, you need to be careful drilling the hole.

Compare this with a 10mm dia. shield anchor (Rawlbolt) where the nominal
hole size is 16mm and the maximum is (not stated by Rawl but) probably in
excess of 18mm, so a much bigger hole but much more leeway on the hole
size.
=========================================

I would guess that this is a case of a specialised product finding a more
mundane use because it's so versatile. It's always the responsibility of a
user to satisfy himself that an item is fit for purpose. The fact is that
these things can be undone and re-used but probably not more than once or
twice, and not in critical situations.

Cic.


--
==========================================
Using Ubuntu Linux
Windows shown the door
==========================================

Dave Osborne wrote:
Cicero wrote:
On Fri, 01 May 2009 17:39:53 +0100, george (dicegeorge) wrote:


I'd also recommend multimonti - I think some very long ones are
available now.

Are the multi-monti better than the bolt things which expand?

Do you just drill a pilot hole with a sds drill then drive them in
with an impact driver?

Do they unscrew, or is that that once they're in they're in?

[g]

=========================================

Screwfix give a good description of their usage including drill
size(s) required:

http://www.screwfix.com/prods/45200/...50www.screwfix

http://tinyurl.com/chc8h5

Cic.

I notice that the Screwfix blurb cites "reusable", but the technical
approval (sec. 4.2.2) specifically states "The anchor may be used only
once".

I've reused them many times e.g. put them in, realised it wasn't in the
right place, re drilled & reused them many times.

Also, it seems they are only suitable for static or quasi-static loads
and have a design life of only 50 years.

Only? I'll be getting a telegram form the Queen before then :-)


For the 10mm dia. bolt, the nominal hole size is 8mm with a maximum
size of 8.45mm. So yes, you need to be careful drilling the hole.

Not that careful in my experience. Normal 5 or 6mm bit, bog standard SDS,
no real problems.

Compare this with a 10mm dia. shield anchor (Rawlbolt) where the
nominal hole size is 16mm and the maximum is (not stated by Rawl but)
probably in excess of 18mm, so a much bigger hole but much more
leeway on the hole size.

And much more chance of the expansion cracking the brick/concrete.

Also a 5 or 6mm hole is less stressful to the substrate than a 5 or 6mm
hole.

I can only quote from my experience, but the 7.5mm are really easy to use &
incredibly strong & reliable.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Owain wrote:
The Medway Handyman wrote:
Only? I'll be getting a telegram form the Queen before then :-)

Why, did you forget to count the corgis before screwing down the last
piece of decking?

Don't you mean 'count the gas safes?


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "js.b1" saying
something like:

Still
most roofs are still standing held together with little more than a
big nail at an angle with more attention to the finger & cigarette
position than wood, nail & hammer.

That's a good point and it's just as well for most of us that during
construction things tend to stay where they're put.
The standard of workmanship I've seen in the construction industry would
boggle your mind.

On 3 May, 14:13, Grimly Curmudgeon
wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "js.b1" saying
something like:

Still
most roofs are still standing held together with little more than a
big nail at an angle with more attention to the finger & cigarette
position than wood, nail & hammer.

That's a good point and it's just as well for most of us that during
construction things tend to stay where they're put.
The standard of workmanship I've seen in the construction industry would
boggle your mind.

Another vote for resin - also keeps water from entering the hole