What is this?

[dezertrider]

I am hoping someone can help me identify what this is and how to fix it. We purchased a new build in Havasu in the a new development. Grading is less than 2 years old. In a couple of areas we have this white salty looking stuff coming up through the grout lines. I have seen water pool up and I am assuming it’s a by product of moisture seeping up. It’s nowhere near any plumbing. My builder has no idea what it is and I can’t find anything online.

View attachment IMG_1023.jpeg View attachment IMG_1025.jpeg

 

[Wizard29]

I believe that's something called efflorescence. Pretty common out there. Caused by moisture/vapor coming through the concrete and bringing salts with it. After the moisture evaporates, those salts are what's left behind.

Read more here:

Concrete Efflorescence - Causes, Removal & Prevention - Concrete Network

Efflorescence is a white powder seen on the surface of concrete, caused by vapor migrating through the slab, bringing salts to the surface.

www.concretenetwork.com

 

[wet hull]

Efloresence. They make a dissolver you can get at tile stores. Mix with clean water and let it soak. Will dissolve the crystals then mop off or wet vacuum. Will always be a issue especially if they only used standard grout.

 

[NicPaus]

Yep some thick efflorescence.
The last trip at Parker. It looked like it snowed at the upper sandbar from previous rain.

It's a masons worst nightmare. Dealing with it on a house I am working on now.

 

[dezertrider]

Yep some thick efflorescence.
The last trip at Parker. It looked like it snowed at the upper sandbar from previous rain.

It's a masons worst nightmare. Dealing with it on a house I am working on now.

I am trying to find a solution for my builder. It’s getting worse with the wet weather. I would love to find an easy fix. The builder is willing to fix it if we can pin point a solution

 

[lbhsbz]

I am trying to find a solution for my builder. It’s getting worse with the wet weather. I would love to find an easy fix. The builder is willing to fix it if we can pin point a solution

Sign up and post up here: https://www.johnbridge.com/vbulletin/

The RDP of tile work

 

[NicPaus]

Here in CA

I am trying to find a solution for my builder. It’s getting worse with the wet weather. I would love to find an easy fix. The builder is willing to fix it if we can pin point a solution

Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs. The foundation I was setting up yesterday. Calls for 4" of sand over 6 mil in the garage. The dirt has a lot of clay. So I am compacting base first. Then a little sand, 6mil and the remaining sand.

Not sure what a good fix would be for existing. Possibly pouring a 3'-5 walkway around the whole house to keep the rain from seeping in close to the house. But it could be a ground water issue if water table is high and it rises during storms.

 

[TonyFanelli]

If it's a new build, wouldn't it be the contractors deal to fix it?

 

[zhandfull]

I’m going with add a vapor barrier under the slab. Surely that is a standard requirement now days right?

 

[zhandfull]

Here in CA
Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs. The foundation I was setting up yesterday. Calls for 4" of sand over 6 mil in the garage. The dirt has a lot of clay. So I am compacting base first. Then a little sand, 6mil and the remaining sand.

Not sure what a good fix would be for existing. Possibly pouring a 3'-5 walkway around the whole house to keep the rain from seeping in close to the house. But it could be a ground water issue if water table is high and it rises during storms.

I’ll add rain gutters on house to direct water away from foundation.

 

[Javajoe]

That is a huge issue. Efflorescence is not something that just goes away. I’ve dealt with it over the years but have never seen it that bad. That’s why they install vapor barriers. You builder should know better. People sometimes even still get it

 

[Sharky]

Here in CA
Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs.

Vapor barrior.

Extremely common out here.

 

[NicPaus]

I’m going with add a vapor barrier under the slab. Surely that is a standard requirement now days right?

In CA yes. Not sure about AZ. Last few years I have putting base down under every pour. Had a few issues where the dirt in some areas stays wet for long periods after rain and the slab coloration looks uneven.

The AZ Concrete guy I know. Said they don't use rebar in there flatwork. As the certain minerals will eat it and it will rust out. I told him just put 6mil down. Nope. Takes to long to finish the mud. So he never uses rebar.

 

[hallett21]

Here in CA
Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs. The foundation I was setting up yesterday. Calls for 4" of sand over 6 mil in the garage. The dirt has a lot of clay. So I am compacting base first. Then a little sand, 6mil and the remaining sand.

Not sure what a good fix would be for existing. Possibly pouring a 3'-5 walkway around the whole house to keep the rain from seeping in close to the house. But it could be a ground water issue if water table is high and it rises during storms.

I’m going with add a vapor barrier under the slab. Surely that is a standard requirement now days right?

They don’t do a vapor barrier in Havasu. I guess because it’s not required? Tried to have it done on our Casita and was basically told no.

Our house has it pretty bad (concrete floors). We’ve tried sealers, scrubs, cleaners you name it. The only solution is routine mopping of our floors. Luckily they’re smooth, tile and grout would be a pain. Gonna need a big scrub brush.

 

[hallett21]

In CA yes. Not sure about AZ. Last few years I have putting base down under every pour. Had a few issues where the dirt in some areas stays wet for long periods after rain and the slab coloration looks uneven.

The AZ Concrete guy I know. Said they don't use rebar in there flatwork. As the certain minerals will eat it and it will rust out. I told him just put 6mil down. Nope. Takes to long to finish the mud. So he never uses rebar.

Is that new fiberglass rebar any good? I’d imagine it’s more resistant than steel.

 

[Sawtooth]

Like others have said it is efflorescence, aka alkali, leaching from the concrete and up through the slab from the soil beneath. Whenever we used to pour a slab in CA. it was required that we put down 3” of sand then 6 mil Plastic over that and then covered with another 3” of sand to prevent moisture from rising up and causing damage. Unfortunately about the only thing that can be done to remedy this problem now would be to remove the tile and seal the slab with something like HydroBan by Laticrete or even RedGuard by Customs and then install new tiles.
I’ve heard stories where this efflorescence is so bad it has broken the bond of the thinset between the tiles and slab.
I’m not aware of any products that can be applied to the grout joints to alleviate this but maybe Joker here on RDP might know as I think his profession is waterproofing.

 

[NicPaus]

On my plans that are for existing garages turned into ADU. They call for redguard on the slabs for moisture barrier. I use Hydroban instead.


If the builder has some in progress but not tiled yet. Hydroban the slabs before tile. Or laticrete fracture ban. Uncoupling membrane-moisture barrier.

 

[Sleek-Jet]

In CA yes. Not sure about AZ. Last few years I have putting base down under every pour. Had a few issues where the dirt in some areas stays wet for long periods after rain and the slab coloration looks uneven.

The AZ Concrete guy I know. Said they don't use rebar in there flatwork. As the certain minerals will eat it and it will rust out. I told him just put 6mil down. Nope. Takes to long to finish the mud. So he never uses rebar.

I had a house built in Tucson about 15 years ago, and there was no barrier placed down before the foundation was poured. Ended up with the white residue on the stucco after our first winter.

 

[500bbc]

On my plans that are for existing garages turned into ADU. They call for redguard on the slabs for moisture barrier. I use Hydroban instead.


If the builder has some in progress but not tiled yet. Hydroban the slabs before tile. Or laticrete fracture ban. Uncoupling membrane-moisture barrier.

Vapor barrier, 10mil in any area with ground water problems, then waterproof membrane applied to slab before finish floor.
Water table south of Ventura Blvd in the SFV is very high. Priced a job where the entire downstairs was marble laid over existing slab with no waterproof membrane, bad efflorescence entire floor, they went with the cheaper price. They also had ceiling cracks below the new master bath with the tile floor cracking as well. They moved their massive shower to the center of the space and finished it off with full slabs to the 10' ceiling. I asked him about the structural that was done to handle the weight, he answered "Huh?".

Only fix for the OP is to remove all finished flooring, install high quality waterproofing and reinstall all flooring. Waterproofing from the negative side can be a crap shoot.

 

[4Waters]

Hunter biden is the expert in white powder

 

[boatpi]

Builder too cheap or stupid to use a vapor barrier

 

[AQUA-HOLICS]

Is that new fiberglass rebar any good? I’d imagine it’s more resistant than steel.

A few pool builders back east are starting to use the fiberglass bars only on the straight runs due to it cant be bent on the job site, only at the factory.

 

[2Driver]

Dealt with this in havasu and at the river house. The soil was always wet and throwing off efflorescence at the river house. At the river it would eventually rust the rebar, it would expanded then pop the slab. I had a section of garage slab the size of a frisbee 4” deep just pop out one day. At the bottom was an enlarged section of rusted rebar. In havasu it creeped up the outside and pulled the stucco off where the ground got wet from rain or irrigation bubblers.

I don’t think you can stop it now except to inspect and make sure the slab stays as dry as possible. Id just be sure you don’t have a small slab leak or irrigation leak (over watering too) or drainage issue. If the slab under stays dry you shouldn’t be getting it. I have never seen it coming out of the tile grout. So I’d have to say it is really wet beyond what it should be in that area under the slab.

They make some efflorescence remover products to neutralize the stuff. It can be in the grout and thin set due to the water they used to mix the grout but Its usually just a white film not bubbling up. I’d bet it’s moisture in or under the slab from water or seepage moisture. The trick is to find the source of the wetness. Tap the tiles to be sure they are all solid.

 

[NicPaus]

Is that new fiberglass rebar any good? I’d imagine it’s more resistant than steel.

Never used it. I have my 1" Bender in my truck now and the 1" cutter in my living room. No way I could lift the bender out last night when I got home.
How do you make stirrups and bends?

 

[Mandelon]

Moisture moves through the concrete and dissolves the salts in the slab. The salts travel along with the water as the hydroscopic pressure moves from wet to dry. Water evaporates leaving the salts behind. The salts aren't dangerous or anything.

However the condition is indicative of a moisture issue. These can result from poor grading to a water or drain pipe that is compromised. Is there any muddy areas around the yard? I know, its Havasu...LOL probably not. Uphill neighbor with a leaky pool maybe?

Using a non penetrating moisture meter, you could take readings around the floor to see if it is higher in any particular areas. this could indicate a pipe is leaking. Is the water service run overhead in the attic and walls vs under the slab?

Perimeter grading should have a slight gradient to move surface water away from the foundation. 1/4 per foot for five feet is what the engineering reports always say. There should be a few inches of slab visible below the weep screed where the stucco ends. don't just pile dirt up against the house. Rain gutters and downspouts are a good plan, make sure the downspouts direct water well away from the foundation.

Even with 6 or 10 mil poly under the slab, the exterior edge of the foundation is still exposed and subject to absorbing water. That area can be waterproofed if necessary and a perimeter French drain can be installed.

It can get pricey, but solving the moisture issue is most likely your best plan of action. Even if you do pull up the floor and waterproof the slab on top, I think it is better to solve the problem itself and not just the symptoms.

 

[obnoxious001]

Brian,, down here after a good rain it looks like it has snowed outside. My home is raised, but the shop has a couple of spots were it wants to come through, along with the slab between the two buildings. The edges of the concrete deteriorate pretty rapidly. Even rinsing with tap water, or dish soap and water has proved helpful. Someone told me something the other day, I will see if I can catch him to get him to remind me what to use. I thought they told me they had a layer of plastic under the slab, seems like the biggest problem in my eyes are the edges getting eaten away.

 

[Javajoe]

Any builder that doesn’t put a vapor barrier under a slab is either lazy or cheap or both. Hydrostatic moisture is a big thing that pushes flooring off of floors. Efflorescence is not the only issues that will arise. Concrete finishes the same with or without it. I’ve poured directly on vapor barrier but normally with a few inches of sand on the VB.

 

[AQUA-HOLICS]

Never used it. I have my 1" Bender in my truck now and the 1" cutter in my living room. No way I could lift the bender out last night when I got home.
How do you make stirrups and bends?

At the current time you can’t bend it on the job site, has to be ordered with the bends already made to them.
This is the big downside to swimming pool use, the excavation of the pool is rarely close enough to the plans to have the bars bent off site.

 

[Nordie]

Never used it. I have my 1" Bender in my truck now and the 1" cutter in my living room. No way I could lift the bender out last night when I got home.
How do you make stirrups and bends?

It would have to be in a mold. There's epoxy coated that would be better anyhow. It's not very common in the desert, but it's pretty much used everywhere else.

We even did some stainless rebar in a hospital, something to do with very powerful magnets.

Back to the OP, when I was in Florida I dealt with an area of stone that faced the beach that I could never get rid of the efflouressence. I recently talked with a PM that got it figured out after a hurricane. There was a tear on the vapor barrier at that spot.

With it coming through the slab like that I think the all the tile has to come up. Might be a good idea to have them put down Schluter Ditra mat on the slab and tile in top of the ditra.

This is what I used to clean efflouresence before, stuff is pretty nasty, but was effective. Seemed like a toilet bowl cleaner on steroids.

 

[CSmith]

I’m going with add a vapor barrier under the slab. Surely that is a standard requirement now days right?

You would think. Havasu is known for this issue and still on majority of all new construction I still don't ever see a vapor barrier.

 

[sonicss31]

Is that new fiberglass rebar any good? I’d imagine it’s more resistant than steel.

If I’m not mistaken fiberglass rebar is what was used and is still in the structural beams of the 7 Mile bridge in the Keys. Bridge was built in the early 1970’s.

 

[Mandelon]

Arizona Polymers make a couple epoxy coating to go over a wet slab. APF Epoxy 100 and 300 I think. They roll on thick and gooey but keep water from passing through. Another option is a couple coats of Xypex Concentrate. It grows crystals inside the slab and they retard capillary action.

 

[Ultra912]

I am now hanging 6 mil around the perimeter of foundations leaving a skirt of visqueen between footing mud and native soil footing walls. Stapled to the bottom couple inches of forms and hanging down into footing.

Once it has contaminated an area it never goes away,,,,,,at least outside. My retaining walls have some areas where the blocks have been ruined due to it happening seasonally. My driveway gets a gigantic area every year as well. In the 80's FHA required vapor barriers but Conventionally financed builds were not required to. I have yet to use the fiberglass rebar. Next time I get work on the local lake I'll give it a shot.

 

[SoCalDave]

The AZ Concrete guy I know. Said they don't use rebar in there flatwork. As the certain minerals will eat it and it will rust out. I told him just put 6mil down. Nope. Takes to long to finish the mud. So he never uses rebar.

Interesting perspective there Nick.

 

[DRYHEAT]

Just an observation. In the late eighties/early 90s I drove a cement mixer in town and never saw vapor barrier on any residential builds. The only place I ever saw it was commercial buildings.

 

[white tortilla]

Builder too cheap or stupid to use a vapor barrier

“My Havasu builder doesn’t know what it is” LMAO. Right

 

[Melloyellovector]

With out ripping foundation out, to late for vapor barrier. So no point in saying what they should have done.

Best bet is remove tile, coat slab with zypex, then install shluter membrane, then use litokol epoxy grout.
this separates the tile from the foundation, and epoxy grout is non cement based = No more efflorescence

 

[Berdes]

Here in CA
Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs. The foundation I was setting up yesterday. Calls for 4" of sand over 6 mil in the garage. The dirt has a lot of clay. So I am compacting base first. Then a little sand, 6mil and the remaining sand.

Not sure what a good fix would be for existing. Possibly pouring a 3'-5 walkway around the whole house to keep the rain from seeping in close to the house. But it could be a ground water issue if water table is high and it rises during storms.

This^ Specifically the plastic vapor barrier I think.

 

[dezertrider]

With the recent rain it has gotten worse. Sounds like I need to just clean it up and keep the area outside as dry as possible. This isnt an easy fix and I dont think anyone is laying down plastic under the foundations here in Havasu.

Thanks for all the information.

 

[DLC]

Rebar gets eaten from the minerals then it expands and can pop loose the concrete as the rebar rusts and expands

I haven’t seen anyone use a VB in Havasu.

Keep in mind all the minerals are ALSO mixed in the concrete. Water isn’t filtered, sand and rock are sourced locally

Any white around the drive way, walks, patio, garage
talk to your neighbors and see if they have any issues inside


To lessen the amount of water add gutters and dump them into drain pipes & add area drains where needed in landscape - you want to get it out & away from the house

 

[DLC]

My neighbor uses a vinegar and water solution to get rid of the white on his driveway and walk areas

 

[samsah33]

All over my pool and spa outside...

I also get that on the floor of a 2nd story tiled shower - should I be worried...?

 

[Justfishing]

Here in CA
Here we put 6mil plastic down before we pour any slabs inside a house and garage slabs. The foundation I was setting up yesterday. Calls for 4" of sand over 6 mil in the garage. The dirt has a lot of clay. So I am compacting base first. Then a little sand, 6mil and the remaining sand.

Not sure what a good fix would be for existing. Possibly pouring a 3'-5 walkway around the whole house to keep the rain from seeping in close to the house. But it could be a ground water issue if water table is high and it rises during storms.

Do not put sand on top of poly. The slab should go directly on the poly. Water can get between the sand and poly defeating poly

 

[NicPaus]

Do not put sand on top of poly. The slab should go directly on the poly. Water can get between the sand and poly defeating poly

It's what's specd by the engineer on the plans. Personally I would prefer compacted base, 1/2" or so of sand, 6mil then slab.


The slabs over sand always seem to Crack more than normal. But I need to pass inspection.

 

[Mandelon]

I think they want the sand over plastic to keep it safer from being damaged by everybody walking all over it setting the rebar and getting ready for the pour. I guess if you don't have rebar, then you won't be walking on the plastic much.

 

[rmarion]

Moisture moves through the concrete and dissolves the salts in the slab. The salts travel along with the water as the hydroscopic pressure moves from wet to dry. Water evaporates leaving the salts behind. The salts aren't dangerous or anything.

However the condition is indicative of a moisture issue. These can result from poor grading to a water or drain pipe that is compromised. Is there any muddy areas around the yard? I know, its Havasu...LOL probably not. Uphill neighbor with a leaky pool maybe?

Using a non penetrating moisture meter, you could take readings around the floor to see if it is higher in any particular areas. this could indicate a pipe is leaking. Is the water service run overhead in the attic and walls vs under the slab?

Perimeter grading should have a slight gradient to move surface water away from the foundation. 1/4 per foot for five feet is what the engineering reports always say. There should be a few inches of slab visible below the weep screed where the stucco ends. don't just pile dirt up against the house. Rain gutters and downspouts are a good plan, make sure the downspouts direct water well away from the foundation.

Even with 6 or 10 mil poly under the slab, the exterior edge of the foundation is still exposed and subject to absorbing water. That area can be waterproofed if necessary and a perimeter French drain can be installed.

It can get pricey, but solving the moisture issue is most likely your best plan of action. Even if you do pull up the floor and waterproof the slab on top, I think it is better to solve the problem itself and not just the symptoms.

This

 

[rmarion]

With out ripping foundation out, to late for vapor barrier. So no point in saying what they should have done.

Best bet is remove tile, coat slab with zypex, then install shluter membrane, then use litokol epoxy grout.
this separates the tile from the foundation, and epoxy grout is non cement based = No more efflorescence

This

 

[rmarion]

With it coming through the slab like that I think the all the tile has to come up. Might be a good idea to have them put down Schluter Ditra mat on the slab and tile in top of the ditra.

again this

 

[Nordie]

again this

Basically it's never going to go away unless you put a membrane in between

 

[rmarion]

Basically it's never going to go away unless you put a membrane in between

Ditra

Dry underlayment. Floats over existing concrete floor. Concrete sub floor will expand and crack without damaging new tile instalation.
Seal inside seams to maintain Vapor Barrier. Leave perimeter unsealed, un grouted. Allows it to breathe. Apply new Base board with airgap space to breathe.

Follow all manufacturers installation guidelines.

Schluter-Ditra Uncoupling Membrane | Floor & Decor

Specifically Designed For Ceramic And Stone Tile Installations Ditra Provides Uncoupling To Prevent Cracked Tile And Grout. Ditra Also Serves As A Waterproofing Laye

www.flooranddecor.com

Nordie... you posted about this product. I agree with this product.


PS... my Sons home purchase of 1960 track in Corona... had two concrete subfloor cracks... I installation travertine over the crack... I applied loose laid sux foot, 80 mil TPO membrane
over crack, and backer rod, sealant... 12 years no cracks in the tile and grout... that concrete floor is still moving..


JohnBridge.com Great Fourm... lots of PRO's in that site... shit my post about my sons cracked floor is there..


Mandelon is on the money ... get all exterior drainage away from the house by whatever means.... test soil for moisture... maybe broken line like Mr. M said...


Good luck OP