New house white appearing on bricks

[Bobbya82]

Hi there,

Hopfully this is the right forum?

Just a quick question, I have recently moved into a new house and have noticed that there is white colour appearing near the bottom of the back walls.

Is this normal or is this something to worry about.

Let me know if more detail is needed.

Thanks in advance.

 

[JohnD]

It is most likely efflorescence. On a new house it happens as the brickwork dries out, and the dissolved minerals and salts from the mortar rise to the surface. You may be able to brush it off, or it will weather away in time. It will stop when the walls have finished drying. In this case it is nothing to worry about. You will see it in other local houses built at the same time.

Don't try to hose it off, this will just cause more moisture to evaporate, and more salts to come out.

On an older house, it is more likely to be caused by damp, including drips and splashes from gutters and taps, making the brisks wet, and the water bringing dissolved salts to the surface as it evaporates out.

If you have an area where it is unusually thick, or unusually persistent, investigate for sources of damp. If it is below the DPC then ignore it.

 

[^woody^]

"near the bottom of the back walls" ...... is this above or below the DPC?

 

[Bobbya82]

I think it is below the damp course but would have to check and confirm.

What are thinking it might be then?

Thanks for the responses.

 

[JohnD]

groundwater

I get it, I am on chalky ground, so the walls below the dpc are damp with hard water and dissolved limescale which lies on the surface when the water evaporates.

post a pic if you can

mine looks like

 

[^woody^]

If its below DPC then it will be there forever.

If it is above, then it may only last 30 years or so

I have these bumper stickers for sale "Efflorescence is for life, not just for Christmas"

 

[Bobbya82]

Hi,

Here is a photo.

Thanks for the help.

 

[jeds]

As John says, it's effluorescence. The standard remedy is to brush it off with a dry brush - but it doesn't always want to come off easily. A pressure washer will clean it off initially but will most likely make it worse in the long run so is generally considered a bad idea. Having said that I have known people do it against advice and have some success. It's harmless when on the surface so nothing to worry about except being a bit unsightly.

 

[JohnD]

I can't see the DPC on that pic. Have a look round the house and see where the DPC is. If the paving has been laid above the DPC it will cause a damp bridge and the paving will have to be lowered.

DPC should be two courses of bricks above ground level to prevent rainwater splashing up.