Dampness in Wall 1

[farhanjnawab]

Dear All,

Background:

There is a masonary building wall which is affected by dampness / moisture in the middle half of its height. There are no concealed water pipe lines, drainage etc, neither there are any cracks for the outside moisture to penetrate.

Query:

Why is this wall damp at the centre? and how to repair it permenantly?

Pls help

 

[bimr]

You have not stated the environmental conditions. Is it possible that you have a problem with humidity and condensation.

 

[farhanjnawab]

Sir, the area is very hot in summer around 46 degrees and minimum temp drops to 10 degs in winter. If humid it should affect the other portion of the wall...

 

[Ron]

There is a possibility that the localized accumulation of moisture is related to the coating on the exterior wall. Either a breach of the coating (fine crack(s)) or a thin application of the coating has likely allowed moisture to selectively accumulate in the area. Based on your weather conditions, there is no vapor drive toward the exterior, so it can stay indefinitely within the area.

I would suggest that you have an infrared thermographic scan done of the area to delineate it. You might also show the anomalous problem that is causing it by this method.

Once the source/cause is known, it is relatively easy to correct it.

 

[bimr]

With the limited information that you have provided, one would suspect that you are lacking a vapor barrier on the interior side of the wall. The outside temperature may be dropping low enough each night to cause condensation. You would definitely get condensation in the winter.

http://www.blueflame.org/datasheets/humidity.html

 

[Ron]

bimr...a vapor barrier on the inside of a wall with those exterior environmental conditions would be a mistake. For a 40C temperature, the vapor drive is inward. Vapor barrier should be on the exterior.

 

[bimr]

The location of the vapor barrier depends on the climate which the poster has not provided.

The poster has also not provided any details on the building loads or usage.

The minimum temp drops to 10 degs in winter. With the winter condition, a vapor barrier on the exterior side may not be a good recommendation.

Further details on the application are needed.

 

[bimr]

You may have the condition known as "rising damp". Rising damp describes the action of ground moisture rising up a masonry wall by capillary action.

http://en.wikipedia.org/wiki/Damp_(structural)

The links to these Building Science articles discussing building construction may assist you:

http://www.buildingscience.com/docu...vestigating-and-diagnosing-moisture-problems/

http://www.buildingscience.com/docu...agement-and-vapor-control/reservoir-claddings

 

[Ron]

bimr....Not likely! "Rising damp" cannot occur as an isolated incident in the middle of the wall. This condition is related to "wicking" at the base of the wall under extreme moisture conditions. Moisture does not travel 1/2 way up a masonry wall by capillarity.

 

[hokie66]

Ron, certainly rising damp can't be half way up the wall without affecting the base of the wall. But it can indeed travel a long way up, and I have seen it 1.5 metres up. I don't think rising damp is indicated for the OP's case, if he has described his problem correctly.

 

[Ron]

hokie66...I've also seen it rise relatively high up a wall (not 1.5 meters), but certainly high enough to be concerned. My point was that there is a dry gap between..so not likely the moisture came up from the base, as you noted.

 

[bimr]

Don't recall seeing the height of the building wall mentioned. 1 meter may be 1/2 of a 2 meter high wall.

There is adequate information presented in the building science articles that the poster can develop his own ideas as to the cause of the problem.

The poster should have much greater knowledge of the details of the construction than he has presented.

I see no reason to state definite solutions when the scope of the problem needs additional clarification.