Efflorescence on house considering buying

[alanjbee]

Hi All,

New to this forum so any advice gratefully appreciated.

I'm looking at buying a house but the front wall has a white deposit over large portions. Searching online it seems to be 'effloresence'.

See attached pic.

White deposit

• alanjbee
• 7 Jun 2015
• 1

The white deposit covers about 60% of the front wall but not any of the side or rear walls. It isn't uniform on the front, affects some areas but not others.


I thought sea air might be a cause, the house is SSW facing and on a hill. A couple of other houses on the road seem similarly affected, not all of them but some other houses use different bricks.

Not entirely sure of the age of the house, estimate between 30 and 45 years old.

So... is this something I need to be worried about, i.e. is it something cosmetic and easily cleanable or is it something fundamental & likely to cause the bricks to weaken? If I clean it off (wire brush and water?) will it keep coming back..

Thanks

Alan

 

[JohnD]

IMO it will be caused by a severe water leak (unless there is a gutter above constantly spewing water on the wall), and it is a hard-water area or the house is on chalk.

I live on the coast and we do not see that even in areas where windows and cars are constantly marked with spray.

If there is a water meter, look at the bubble by the indicator. Is it ever still?

If the floor is concrete, it could be a lot of work to fix.

If you are really lucky, it will just be a radiator or heating pipe.

As you are on a hill, there is a chance water is running down and wetting the wall. In which case the mark should stop precisely at the DPC.

 

[theprinceofdarkness]

Don't take a wire brush to the bricks, you will permanently mark them. Give the wall a good soaking with a hose then apply a brick cleaner (mild acid) this should clean the bricks up. if you don't soak the bricks the cleaner just soaks in and disappears.
Frank

 

[tony1851]

It's common on new brickwork as it dries out and is perfectly normal, but not on an older house.
In older houses, it suggests the presence of dampness, such as failed dpc, gutter leak, leaking pipe etc. But as there are several houses nearby with this, that seems unusual.
It's generally just an aesthetic problem, though some bricks can be damaged by the salts forming just under the surface.

 

[^woody^]

Dry brush only. Water dissolves the salts back into the wall, only to reappear when the water evaporates out.

If this is efflorescence, it has no detrimental effect on the wall.

 

[joe-90]

It's caused by interstitial condensation. Warm moist air transmigrates and cools inside the bricks, then evaporates leaving the salts behind. You'll never get rid of it but it does no harm.

 

[^woody^]

What about on garden walls or block paving?

 

[JohnD]

It's caused by interstitial condensation. Warm moist air transmigrates and cools inside the bricks, then evaporates leaving the salts behind. You'll never get rid of it but it does no harm.

Warm moist air and condensation contain only pure water, with no mineral salts.

That wall appears to have more minerals on the surface than the mortar or bricks would have contained unless extra, hard, water was added for example from a leak or from groundwater.

It would be interesting to see the whole house, including ground level, DPC position, and the roof/gutters. The deposit appears to be only at the lower part of the wall. It appears to be a cavity wall. No airbricks are visible.

 

[noseall]

It looks to me like one of those house walls you see built on severley sloping ground, i.e. where large portions of sub-DPC masonry are visible.

 

[JohnD]

'mmm, yes.

I am on chalk, and have mineral and lime on the bricks up to the DPC (only two and a half courses above paving though)

I wonder where ground level is, and if it is a retaining wall.

 

[jeds]

It looks to me like one of those house walls you see built on severley sloping ground, i.e. where large portions of sub-DPC masonry are visible.

That was my thought. Are the affected areas of wall below floor level? A photo of the wider house would be useful.

 

[Flyboytim]

Could the pallet of bricks showing the salts have been subjected to flooding or excessive water soaking before the building was built?

The lower courses and some isolated rows of bricks above are affected, but there are some bricks between that are apparently unaffected.

These bricks are flettons - with the "kiss marks" from firing, and naturally have a microscopic spongy cracking structure (which often causes frost spalling on exposed situations when built into garden walls), and thus when soaked, may absorb water and then leach out contained salts on repeated drying events over time.

An acid salt removing cleaning treatment may help, but the staining might be rather tenacious, if the deposits contain significant amounts of calcium silicates from cement, which are less acid soluble than carbonates and sulphates.

 

[Joe Malone]

It's caused by interstitial condensation. Warm moist air transmigrates and cools inside the bricks, then evaporates leaving the salts behind. You'll never get rid of it but it does no harm.

Absolute tosh!

 

[Joe Malone]

Dry brush only. Water dissolves the salts back into the wall, only to reappear when the water evaporates out.

If this is efflorescence, it has no detrimental effect on the wall.

Woody is spot on when he says remove with a dry brush (Use a stiff brush not a wire brush) only but salts do have a detrimental effect on bricks because the salt crystals block the pores and trap moisture in the bricks which can expedite hydraulic frost action and spalling of the bricks. Most salts when seen to this degree were in the building materials and so it is inevitable that they would migrate to the surface as the brickwork dried out. I don't agree that it is caused by a leak, particularly since we must be dealing with a cavity wall and the external spoiling is quite random.

 

[KenGMac]

Another at times major cause of Efflorescence is the use by the brickLayer of Washing up liquid as a plasticiser in place of the more expensive proprietary cement Plasticiser.
Plasticiser is used to make the Mortar "Flow" and if it is added the brickie has an easier job.
Ken