Examining block work under plaster
 

Is there a way of establishing the structure and integrity of a block wall
without removing the covering plaster? X-rays? Some other techy wizardry?

Thanks.

Examining block work under plaster
 

On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?

Thanks.

An IR camera works - different thermal characteristics of the morter v
the blocks.
I discovered this accidentally after lookingat the ceiling for cold
spots in my loft insulation and pointed at the walls when the block and
morter showed up very clearly.

Examining block work under plaster
 

Andy Bennet wrote:

An IR camera works - different thermal characteristics of the morter v the
blocks.

Thanks very much for that. Am I right in thinking that it would be
necessary to remove any obstacles such as shelves, empty bookcases and the
like away from the wall to get a meaningful result?

Examining block work under plaster
 

On 10/03/2020 14:25, Bert Coules wrote:
Andy Bennet wrote:

An IR camera works - different thermal characteristics of the morter v
the blocks.

Thanks very much for that.Â* Am I right in thinking that it would be
necessary to remove any obstacles such as shelves, empty bookcases and
the like away from the wall to get a meaningful result?


Yes you will, as all those other items will just clutter the picture
with there own signature - I assume the point of interest is behind
those?. Obviously wallpaper is ok as it is thermally homogeneous.

Examining block work under plaster
 

Andy Bennet wrote:

Yes you will, as all those other items will just clutter the picture with
there own signature - I assume the point of interest is behind those?.
Obviously wallpaper is ok as it is thermally homogeneous.

Thanks. May I ask what camera you used? And can an image be obtained with
the camera away from the wall, to cover a wider area, or does it have to be
actually in contact?

Examining block work under plaster
 

On 10/03/2020 14:43, Bert Coules wrote:
Andy Bennet wrote:

Yes you will, as all those other items will just clutter the picture
with there own signature - I assume the point of interest is behind
those?. Obviously wallpaper is ok as it is thermally homogeneous.

Thanks.Â* May I ask what camera you used?Â* And can an image be obtained
with the camera away from the wall, to cover a wider area, or does it
have to be actually in contact?

The camera I have is an HTI HT-A1 (easily Googled). I bought it from
AliExpress about 1 year ago mainly for detecting hotspots in
electronics. Operationally it works like any fixed focus point and shoot
camera, and it can record snapshots on an SD card.
Since buying it I have probably revovered the initial outlay in adding
extra insulation to the loft and correcting coldspots around windows and
doors for friends and family.
Also interesting wandering down the street at night seeing how much
'vegetation' people have growing in ther lofts!

Examining block work under plaster
 

Andy,

Many thanks for that. I'll look up that camera.

Examining block work under plaster
 

On 10/03/2020 14:25, Bert Coules wrote:
Andy Bennet wrote:

An IR camera works - different thermal characteristics of the morter v
the blocks.

Thanks very much for that.Â* Am I right in thinking that it would be
necessary to remove any obstacles such as shelves, empty bookcases and
the like away from the wall to get a meaningful result?

And experiment with the heating of the room and waiting before
examining. You will also need a camera where the thermal window can be
adjusted (you may only want to look at temperatures, say, between 15 and
30C and have these displayed as full scale so that you can see minor
temperature differences.

It may not tell you much if the wall has been subsequently
plaster-boarded and then skim plastered etc.







--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Examining block work under plaster
 

"alan_m" wrote:

It may not tell you much if the wall has been subsequently
plaster-boarded and then skim plastered etc.

In this case it's skimmed only. Thanks for that, and the other details.

Examining block work under plaster
 

On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?

Thanks.
if you are worried about some cracking this is normal if no provision
has been mad for expansion....

Examining block work under plaster
 

On 10/03/2020 19:40, Jim GM4DHJ ... wrote:
On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?

Thanks.
if you are worried about some cracking this is normal if no provision
has been mad for expansion....
sorry shrinkage

Examining block work under plaster
 

On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?

Thanks.

If it's cracked there's a problem. If there's no cracks forget it.

Bill

Examining block work under plaster
 

On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?


I think it may depend on just what you mean by "structure and
integrity". Eg if you need evidence that the blocks and mortar were
appropriate/to specification then I think you can't get away without
samples.

If this is part of your long-running neighbour dispute I think you need
to be guided by a surveyor.


--
Robin
reply-to address is (intended to be) valid

Examining block work under plaster
 

On Tue, 10 Mar 2020 18:41:48 +0000, alan_m wrote:

An IR camera works - different thermal characteristics of the
morter v
the blocks.

Not sure a IR camera is going to tell you much about the integrity of
the wall.

Thanks very much for that.Â* Am I right in thinking that it would
be
necessary to remove any obstacles such as shelves, empty bookcases
and
the like away from the wall to get a meaningful result?

Yes otherwise you'll only "see" them.

And experiment with the heating of the room and waiting before
examining. You will also need a camera where the thermal window can be
adjusted (you may only want to look at temperatures, say, between 15 and
30C and have these displayed as full scale so that you can see minor
temperature differences.

Just been able to have a play with a Fluke PTi120 120 x 90 pixel IR
camera. No great surprises apart from one internal wall that is
colder than expected (I suspect it's blockwork spaced from the real
stone wall with gale blowing through the uninsulated cavity).

Great tool for balancing radiators, you can "see" the plume of hot
water entering and rising straight up and judge the rate of flow and
adjust the lock shield valve accordingly. Far easier, quicker than an
IR thermometer and bits of black sticky tape. Especialy on this
system that is very sensitive to adjustments,

The free Fluke software enables you to adjust the scale of saved
snapshots within the stored image range of -20 C to 155 C and
resolution of 0.1 C. So you can have "hot" (white) at say 25 C and
"cold" (black) at 5 C. Snapshots also have a visible (assuming there
is enough visible light!) image stored along with the IR one.

The PTi120 is not exactly cheap though at £700 - £800 inc VAT.

--
Cheers
Dave.

Examining block work under plaster
 

On 10/03/2020 13:45, Andy Bennet wrote:
On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other techy
wizardry?

Thanks.

An IR camera works - different thermal characteristics of the morter v
the blocks.

+1

Also discovered (by accident) that many years back. I was in the main
lab at GEC Sensors playing around with a steerable thermal imaging
turret, and noticed a wall obviously built with large blocks, but could
not seem to see the same wall with the naked eye. To the naked eye it
had a smooth plastered finish!





--
Cheers,

John.

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

Examining block work under plaster
 

Robin wrote:

I think it may depend on just what you mean by "structure and integrity".
Eg if you need evidence that the blocks and mortar were appropriate/to
specification then I think you can't get away without samples.

Yes, that makes sense; thanks.

If this is part of your long-running neighbour dispute I think you need to
be guided by a surveyor.

I'm afraid it is, and I have been (and still am). It's complicated and I
don't really want to go into details here, but it concerns alleged damage
which (again allegedly) can only be assessed from my side. I was wondering
about possible alternatives to stripping away plaster should things ever
come to that.

Thanks to you and everyone else for the thoughts.

Examining block work under plaster
 

On 10/03/2020 19:41, Jim GM4DHJ ... wrote:
On 10/03/2020 19:40, Jim GM4DHJ ... wrote:
On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a block
wall without removing the covering plaster?Â* X-rays?Â* Some other
techy wizardry?

Thanks.
if you are worried about some cracking this is normal if no provision
has been mad for expansion....
sorry shrinkage

Isn't the problem inappropriate mortar mix for the type of block ?.

Don't Modern 'white' solar blocks need a mortar mix that is
a bit weaker than the mix used for bricks or heavy breeze blocks ?.
(allows for a small amount of movement).

You can also build walls very quickly with the 'white' solar blocks
using some form of quick setting adhesive that is much thinner than
a conventional ?10mm mortar bed. Presumably you need a really
string stable foundation though, else any movement would crack
all the blocks.

Examining block work under plaster
 

On 14/03/2020 12:38, Andrew wrote:
On 10/03/2020 19:41, Jim GM4DHJ ... wrote:
On 10/03/2020 19:40, Jim GM4DHJ ... wrote:
On 10/03/2020 13:38, Bert Coules wrote:
Is there a way of establishing the structure and integrity of a
block wall without removing the covering plaster?Â* X-rays?Â* Some
other techy wizardry?

Thanks.
if you are worried about some cracking this is normal if no provision
has been mad for expansion....
sorry shrinkage

Isn't the problem inappropriate mortar mix for the type of block ?.

Don't Modern 'white' solar blocks need a mortar mix that is
a bit weaker than the mix used for bricks or heavy breeze blocks ?.
(allows for a small amount of movement).

You can also build walls very quickly with the 'white' solar blocks
using some form of quick setting adhesive that is much thinner than
a conventional ?10mm mortar bed. Presumably you need a really
string stable foundation though, else any movement would crack
all the blocks.


no... concrete shrinks brick expands...in general...the lighter weight
the block the more shrinkage.....