Efflorescence on Masonry

By Tim Carter
©1993-2009 Tim Carter

Summary: Efflorescence, ugly white stains on masonry, brick and stone, is the result of water getting in and pulling the water-soluble salt out. Masonry needs masonry sealers to stop efflorescence. The dirt around your retaining walls needs to be treated as well.

DEAR TIM: I feel our new home has some serious problems but our builder disagrees. The house is less than 6 months old but we have ugly white deposits that are leaching out of our chimney, a wing wall that juts from a corner of our home and a retaining wall. I feel there must be something wrong for this to happen. The more I scrub the worse the problem gets. What is wrong and what can be done to fix the problem? Andrew M., Loveland, OH

DEAR ANDREW: Don't put the noose around the builder's neck just yet. The white deposits you are seeing are probably not his fault, although there might have been some things he could have done during construction to minimize the presence of the powder. The first thing to realize is that these mineral deposits are just an aesthetic problem. They do not compromise the structural integrity of any of the masonry in and about your new home, but chronic water that gets into masonry can cause problems over time.

The white powder you see is efflorescence. The brick, stone, concrete block, mortar etc. contain water soluble salts that are the source of the white deposits. Soil behind retaining walls can also contain these same salts.

These trapped salts are set into motion when water enters masonry. The water dissolves the salts and carries them through the masonry towards the surface. Sunlight and wind draw the water to the surface but as the water evaporates, the salts are left behind.

This wall has a bad case of efflorescence. The white minerals leaching from the mortar have seriously stained both the stone and the mortar.
This wall has a bad case of efflorescence. The white minerals leaching from the mortar have seriously stained both the stone and the mortar.
The salts contained in the brick, mortar, stone, concrete block eventually exhaust themselves and the white mineral deposits simply go away. But salts within soil can persist for decades. Each time you try to wash the chimney and wall surfaces to remove the salts, you actually compound the problem. The water you use simply soaks into the masonry surfaces and dissolves the salts to create more problems days later. The surfaces typically look fantastic when wet, but the white powder appears again when the surfaces dry.

To stop the efflorescence now, you must stop all water from entering the masonry surfaces. This is somewhat easy to do at the chimney and any exterior masonry walls, but far more difficult to do with the retaining wall. If you stop the water, there is no transport medium to carry the soluble salts to the surface where you will see them.

The chimney and wing wall can be treated with a siloxane silane/water repellent. They can also be coated with a new clear masonry sealer that bridges cracks up to 1/8 inch. Using these products in tandem virtually assures that you will stop water from getting into the masonry.

Here is classic efflorescence. This brick is at my daughter's school and is only 2-years old.  This is a small wing wall and the top of it can get wet. Efflorescence is very common on new brick and stonework.
Here is classic efflorescence. This brick is at my daughter's school and is only 2-years old. This is a small wing wall and the top of it can get wet. Efflorescence is very common on new brick and stonework.
The retaining wall that is backfilled with dirt should have been treated with a waterproofing compound that would have stopped water infiltration into the wall. That is very hard to do now as the fill behind the wall will have to be removed, the wall cleaned and allowed to dry and finally the back side of the wall can be waterproofed. The builder should have done this when the wall was being constructed. It would have taken minutes instead of the days it will now take to stop the efflorescence.

I would not try to do any remedial work until the weather moderates. You want days where the temperature rises to 65 F or above to get excellent results from the sealants and water repellents. Be sure to inspect the chimney crown for cracks that might allow water to enter the chimney's masonry core. If you discover cracks, you need a different elastomeric coating for the chimney crown.

The one stone in the center bottom of this photograph is completely covered with a thick layer of minerals. It is perhaps the worst case of efflorescence I have ever seen other than deposits in a cave.
The one stone in the center bottom of this photograph is completely covered with a thick layer of minerals. It is perhaps the worst case of efflorescence I have ever seen other than deposits in a cave.

I think you should have a discussion with your builder to see if he will help you out with the retaining wall fix. Perhaps he can excavate the fill and clean the wall and you apply the waterproofing compound. The builder can then backfill since he has access to equipment that can do it rapidly and easily.

Efflorescence happens. It is part of building new things. It eventually goes away on its own, but this process can take years. When possible, it is best to just let the problem diminish on its own.

Stopping water from entering masonry is the best way to make efflorescence stop. But it is not as easy as one might think. Water can enter masonry and travel up, down and sideways! You can actually get efflorescence on masonry walls caused by moisture in the soil that wicks up a wall.



Comments:

Keith Paquin
03 Mar 2008, 14:31
I have what appears to be efervescence coming out of new construction in colored grout for an interior ceramic tile project. My installer is claiming that this was caused by the air temperatures going below freezing in the building before the grout cured. He is also saying to try using trisodium phosphate to clear it up. Is there any merit to the installer's statememnts?
AsktheBuilder
08 Mar 2008, 12:59
Keith,
I hate to ask this, but did you bother to read ALL of my columns on efflorescence? If you did, then you know the answer.
Dick Wolminsk
16 Mar 2008, 20:01
I will constructing a rather large retaining wall this spring and I am attempting to minimize or arrest any efflorescence. I plan on waterproofing the blocks befor backfill takes place but should I also waterproof the face of the wall as well?
AsktheBuilder
17 Mar 2008, 10:28
Dick,
I discuss exactly what to do in my other columns on this topic. There are several columns on efflorescence.
Peter
06 Apr 2008, 16:09
Hi -- We had our 14-unit, 3-story building tuckpointed last year, and it was not cheap ($40k). Now we have severe efflorescence. My question: was this in any way caused by the tuckpointing, and do we have a right to demand that the people that did the tuckpointing "fix" the efflorescence, or at least seal/re-seal the masonry at no cost (is it covered by the warranty?).
Sarah
08 Apr 2008, 20:00
I have a question referring to wicking up a 1/2 brick wall. How do you stop it? The wall was rebuilt last June due to water damage in the inside of the house(original construction was not done correctly, water got behind the brick and rotted out the wall)A year later...almost that tell tale smell of mildew is in the area. Will pro-tec sealer stop it?
AsktheBuilder
10 Apr 2008, 06:11
Peter,
Sure it can be the new mortar. That is natural!!! It is not the fault of the contractor. If you wanted it sealed, you should have requested that up front. Read all of my efflorescence columns and you will discover Mother Nature will take care of this for you.
AsktheBuilder
12 Apr 2008, 10:39
Sarah,
Read all of my past columns on Brick Veneer Water Leaks. That should point you in the right direction.
pat ebrom
19 Apr 2008, 14:44
We purchased a home in Jan 2008. We have the original drafting plans from jUNE 1928. It has concrete block structural walls in the basement. They are showing some efflorescence & browning through former owner putting stain retartdant paint on the walls. Ther is some shifting in the house /walls & cracks are developing in various locations on both 1st floor in walss &some wooden & tile floors, & 2nd floor creeks & walls have drywall seperating from other drywall panels & ceiling;

There was previous roof water damage & new roof put on; There is a temporary jack/beam in the basement.

The cement floor is seperating from the
block walls along the seams in the basement; Water is efflorescing in front around the steps that were pui in much later than when the house was orig. built.

HELP ! ! !
dave schwartz
14 May 2008, 18:12
i have brick patios that the brick has lost its luster and new look...how do I get that look back? If I powere wash it first what do you recommend to do to rejuvenate its look to look new again

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