Is this mold on the floor?

[weatherby460]

Morton pole shed, that is insulated in the walls (with plastic barrier) and blown in insulation in ceiling. What is the white stuff on the floor and what causes it? The one picture is after I swept. You can see the difference by the track on the snowmobile.

Thanks

 

[BillK]

Dust ? Is the floor sealed ?

 

[PCustoms]

Nope

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[Firebrick43]

How long ago was it poured?

 

[weatherby460]

Floor is not sealed. Shed and cement was done in 2017.

 

[weatherby460]

Nope

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How do I stop it?

 

[PCustoms]

How do I stop it?

Looks like cleaning and sealing

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[Fav Onefour]

How do I stop it?

It's tough. Surface sealers alone, won't hold up. Penetrating sealers will be better but you need to do proper prep.

The correct method is moisture management. The efflorescence is mainly from water-water vapor, coming through the concrete. Normal method is vapor barrier before concrete.

How is your ground moisture around the building? I see foam. Were you getting water intrusion? I ask because that my indicate you have high water pressure against the pad if it's coming from outside. That water eventually soaks into the ground. It's possible to prevent some of the efflorescence by reducing ground moisture.

 

[C-S-H]

That might be efflorescence (calcium hydroxide) drawn to the surface by a condensation event. Your concrete mix is supposed to have a pozzolan (fly ash or slag) in it that reacts with the calcium hydroxide (free lime from the cement reaction). Using a pozzolan and moderate water/cement ratio produces a low permeability concrete slab, and stronger too. A silicate densifier will react with the calcium hydroxide near the concrete surface and is your best bet at this point for a partial fix if the white dust is indeed efflorescence.

 

[Improved700]

Not mold. Looks like dust build up and as others have mentioned, could be efflorescence.

Question is... what sled under the cover?

 

[gmcgeo]

efflorescence = salts.

If your concrete is getting moisture it can be drying and leaving the deposits behind

 

[weatherby460]

Thanks all...sounds like it's harmless and not mold.