Message Board Thread - "Help analysing image of discrepencies in the brickwork..."

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Help analysing image of discrepencies in the brickwork... DarrenL 1/15/2010
Hi there,

I recently surveyed this building and noticed the temperature differences of some of the bricks, usually I would suggest missing/insufficient insulation when there are larger patches of warmth on the brickwork. However, in this image the warmer bricks are too small and detailed (you can almost count the number of bricks that are warmer). Looking at the digital image, there is no difference in the surface finish of the warmer areas of brickwork either.

Can anyone suggest a possible cause for these thermal anomalies? Cheers!
 
Re:Help analysing image of discrepencies in the brickwork... StecGuy 1/15/2010
Can you post a digital picture of the exterior?

The patterns could be from the masons installing the brick sloppy. Typically there is a cavity behind brick (for drainage) which makes masonry wall more difficult to scan than most because you don't have a direct conduction line from interior to exterior. What could have happened is the masons used excess mortar and it is filling random locations within the cavity, thus bridging the gap from interior to exterior conditions, allowing more heat to conduct to the outside surface.
 
Re:Help analysing image of discrepencies in the brickwork... DarrenL 1/18/2010
Okay, that's definitely a possibility I hadn't thought of, thanks!

I have uploaded the digital image too, but from this distance it's difficult to spot anything.

I have another batch of images that seem to display the opposite, whereby the individual bricks colder, rather than hotter than the surrounding!

(It won't allow me to post my digital images on here, even after I change the file type! So I've put the other IR image on that I mentioned)
 
Re:Help analysing image of discrepencies in the brickwork... Tony C. 2/9/2010
Evaporative cooling of moisture condensed within the masonry cladding. Check the integrity of the air vapour barrier within the exterior walls. Or Did this wall get wet due to precipitation in the past 48 hours and not have dried out completely prior to the inspection.

We gotta have more info on the inspection methodology and environmental data prior to and during the inspection.
 
Re:Help analysing image of discrepencies in the brickwork... DarrenL 2/10/2010
Tony C. wrote:
tive cooling of moisture condensed within the masonry cladding. Check the integrity of the air vapour barrier within the exterior walls. Or Did this wall get wet due to precipitation in the past 48 hours and not have dried out completely prior to the inspection.

We gotta have more info on the inspection methodology and environmental data prior to and during the inspection.
So if it's evaporative cooling of moisture condensed within the masonary cladding - why does affect specific bricks and not the ones next to them? There was no leakage, no dripping water. Likewise for the first image. I was unable to get inside the building in this instance. The past 48 hours saw slight rain, atm. temp was about 1°C, pressure was 1005mB, rel hum. 85%, light wind. The survey was external only.

Cheers!
 
Re:Help analysing image of discrepencies in the brickwork... Tony C. 2/12/2010
Moisture accumulation is a transient process and there are differences between wetting patterns associated with rain water penetration, vapour diffusion and air leakage from interior sources. Masonry units will absorb and dry out at different rates as will mortars. Mortars will inhibit the flow of moisture from one masonry unit to another. There are many factors that cause variable rates of evaporative cooling and drying of cladding.

Given that you indicate that there was precipitation prior to the inspection, it may have dried out at the surface due to wind and soalr heat gain. Just because masonry appears dry, it may not be completely dry and any drying to the exterior will result in cooler surfaces than normal.

You will need to inspect under different conditions, in order to determine the source of the moisture.
 


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