Time-Tested Performance
Alkali is never pure and rarely stable. It is made up of a combination of elements and almost always reacts with other elements.
We start with hydrogen, then lithium, sodium, potassium, rubidium, cesium and francium. Francium is radioactive with a half-life of only twenty minutes. The other five are very active alkali metals. Each element has electrons and molecules, which are always eager to take part in chemical reactions with other elements. The two most important alkali metals are sodium and potassium. We find a hint of them in potassium carbonate and sodium carbonate. Sodium makes up 2.6% of the earth’s crust and potassium makes up 2.5%, yet we never see them. They are always found in combinations with other elements. Neither of them could remain pure in air or moisture.
The increased use of concrete subfloors in direct contact with the ground makes more important than ever, the complete understanding of moisture and alkali inherent in these subfloors and their effects on paints and floor coverings. Well known as the “alkali problem”, this condition is primarily a problem of moisture. Alkali is present in every concrete slab and is more detrimental with moisture. On adequately ventilated, suspended concrete, subfloor moisture is not present in troublesome quantities.
Where the slab is in direct contact with the ground or a poorly ventilated air space, moisture is brought up through the slab by capillary action. It dissolves the alkaline salts in the concrete and appears at the surface as a destructive alkaline solution causing spalling and efflorescence.
Although moisture and alkali conditions may vary greatly, there is always sufficient moisture in the ground to come in contact with the alkali in concrete to present an “alkali problem” on subfloors affected by ground moisture. It is never safe to assume that a concrete slab will always by dry because is has been dry; moisture content may be small. When paint or floor coverings are applied, the moisture and alkali collects under the coverings. This often results in coverings buckling, warping, or separating from the concrete surface.
Seal-It recommends SEAL-IT Concrete Sealant to alleviate this problem. Seal-It can seal and waterproof the concrete to eliminate spalling and efflorescence, leaving clean pores to which paint, mastics or adhesives for floor covering can effectively secure a better bond. The destructive moisture attacking problems, which causes deterioration to adhesives and paints will also be eliminated.
Efflorescence becomes a problem when moisture is introduced. Moisture transports efflorescence through the concrete, thereby destroying concrete and the steel holding it together. 90% of the problem is moisture; SEAL-IT Concrete Sealant penetrates into the concrete, reacts with the alkali and forms a hydrostatic head, barring the migration of moisture.
*Seal-It recommends certified and trained applicators for alkali sealant solutions.