Damp external brickwork

[jasonbsad]

Hi

Hope someone can shed some light......

After it's been raining, I have noticed a series of adjacent bricks in the same row that appear to get wet/damp. This is the second row from ground level, just below the dpc. After a couple of days without rain, the bricks appear to slowly dry out (see last photo). The bricks and above these appear dry.

Can anyone explain this and advise it anything should be done?

Thanks in advance

 

[KenGMac]

jasonbsad, good evening.

Short answer to your question is "nothing?"

This because, the brick below the DPM is fully exposed to ground water, that is water in the ground that percolates upwards, into the brick work, it is this ground water that is causing the bricks to become wet, obviously in winter, loads of rain the bricks are in effect saturated, slowly drying out in Summer [if we have one?]

On the plus side the DPM appears to be functioning as intended.

On the negative side in the digital images you posted the brick course nearest the ground is also suffering from Efflorescence? a condition where water soluble salt is forced to the surface of the brick and forms a white powder, best way to get rid of this white powder, if you want to is to brush it off. UNDER NO CIRCUMSTANCES at all at all try to wash it off, it is a product that is caused by water??

I would also suggest that you place a thin board of ply on the ground where you brush off the Efflorescence, to catch the powder and do not allow it to get into the ground this will re-energise the appearance of the salt.

If with Hindsight the brick work below the DPM had been more carefully considered and a more water resistant brick should have been specified.

Ken

 

[jasonbsad]

Hi Ken

Thanks for the reply.

In effect, you are saying that damp/water is passing through the ground level brickwork into the brickwork just below the DPM? I will leave as it is unless it causes any issues, though I guess pointing may need attending to at some point.

Dean

 

[^woody^]

It's not as Ken G says.

Your images show that the course below DPC is damp, but stangely, the course below that is not damp - bone dry by the look of it. Normally all the courses below the DPC would be expected top be damp to varying degrees.

The only things that I can think of that could cause this particular phenomenon would be water being trapped in that course - from the cavity coming up or down, or a double DPC or cavity tray of some sort.

Either way, its not a defect or a problem. Nor is the salt staining

Is the house timber framed?

 

[stuart45]

Could be that the cavity was filled a bit higher, and so the water running down comes through on that course, which may be what woody meant.
The original designs for cavity walls had weepholes on the course above the fill, but normally they are only used on timber framed houses.

 

[jasonbsad]

Hi

Thanks for the additional responses.
Yes, the brickwork at ground level does appear dry. The building is a bungalow and not timber framed.

I will just monitor it in case it should cause any issues (i.e. damp inside the house?)

Thanks