Damp external bricks

[Badger76]

Hi all,

I have just removed all my external render and the lower 5 to 6 coarse of bricks are damp there is no damp in the house. There are blue bricks at low level and the render went to ground level could this be the problem ? if so how can I fix it as I am just about to get the the re rendered.

Cheers for any help.

 

[pinenot]

As there is no internal damp you'd be right in thinking that render to ground level may be a cause, but can you expand on the age of the building, what kind of render and why you've taken it off. Also have you any clue as to what type of bricks these blue ones are?

The type of brick asked for above will determine whether they can be left exposed below a bellcast, set just below dpc (if you have one that is) when you reinstate the render. To porous and they will have to be weather proofed with a coloured render, if they are finishing bricks however, cleaning with a hydrochloric solution (brick clean) to remove any laitance and applying a water seal might be an option. Some pics would be a help!
Bellcast - View media item 60668 ...pinenot

 

[Badger76]

Hi,

On closer inspection there are no blue bricks, the age of the property is approx 60 to 80 years not a 100% but will try to find out. I have taken of the render as there was an extension built in 1992 but rendered different to the rest of the house. Not to sure if there is a dpc but here is some pics hope you can help.

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• Badger76
• 30 Apr 2013
• 1

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• Badger76
• 30 Apr 2013
• 1

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• Badger76
• 30 Apr 2013
• 1

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• Badger76
• 30 Apr 2013
• 1

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• Badger76
• 30 Apr 2013
• 1

 

[pinenot]

OK, lets get technical.

Are the walls solid built or cavity?
The airbrick in the 1st pic, is it venting under the floorboards?
Can you mark the approximate ffl on these pics?
The pic showing the render also reveals some pipework and a barrel of some sort??
Is there a distinguishable stop level in the damp height, or any other distinguishable patterns (you've noticed)??...pinenot

 

[Badger76]

Hi,

There is a cavity and my floor level is above the air bricks, the pipe in the pic is for rain water has just been renewed and the barrel is for flowers. The damp hight is at all different levels.

 

[pinenot]

I wonder if it's possible that the original render was allowing moisture to pass through to the brick surface, that would explain the various levels of damp!
Could you remove the laitance from the render cleared walls up to the the airbricks and treat the bare brick with a weather proof solution, what we want is to see if the wet bricks are capable of drying or whether there's another problem causing it.
If all's well you can get the render reinstated, incorporating a bellcast bellow the air bricks leaving a course or two of the substructure bricks above ground level clear. This will ensure no moisture wicks up from the ground via the render, your Rough Caster should be able to advise the level to set it at.