XYPEX Coating Installation
Xypex coating is applied with a semi-stiff nylon bristle brush, push broom (for large horizontal surfaces), or specialized spray equipment.
- General Information
Weather and Concrete Conditions
- The Xypex treatment must not be applied under rainy conditions or when ambient temperature is below 40ºF (4ºC).
- Because Xypex requires moisture to initiate the crystalline waterproofing process, all concrete, whether fresh or old, must be saturated with water. (See Wetting Concrete below.)
- The concrete surface must be a minimum of 20 hours old before application of the Xypex coating treatment.
- For fresh concrete, the period between 24 hours and 72 hours is the optimum time within which to apply Xypex, as the new concrete is still “green” and requires very little pre-watering.
For normal surface conditions, the coverage rate for each Xypex coat is 1.25 to 1.5 lb./sq. yd. (0.65 – 0.8 kg/m2).
- The concrete surface to be treated must be clean and free of laitance, dirt, film, paint, coatings or other foreign matter. The surface must also have an open capillary system to provide “tooth and suction” for the Xypex treatment. A CSP-3 per the International Concrete Repair Institute Guidelines and Surface Profile Chips is recommended.
- If surface is too smooth (e.g. where steel forms are used) or if surface is covered with excess form oil or other foreign matter, the concrete should be lightly sand-blasted, water-blasted, or etched with acid.
- Horizontal surfaces should have a rough wood float or broom finish. Concrete laitance must be removed from surface by light sand-blasting, water-blasting or etching with acid.
- Surfaces to be etched with acid should be dampened with water before application of the acid. After acid etching flush concrete thoroughly with clean water.
Repairs Prior to Coating Application
For cracks larger than 1/64” (0.4 mm) or for actively leaking cracks the following repair procedures are recommended.
- Chip out cracks, faulty construction joints and other structural defects to a depth of 1.5” (37 mm) and a width of one inch (25 mm). A “V” shaped slot is not acceptable. The slot may be saw cut instead of chipped but ensure that the slot is dovetailed or otherwise shaped such that there will be mechanical interlock of materials placed into the slot at a later stage.
- Clean slot, wet concrete and apply a brush coat of Xypex Concentrate (as described below) in cavity and allow to dry for 10 minutes.
- Fill cavity by tightly compressing Dry-Pac into the groove with pneumatic packing tool or with hammer and wood block. (See below for Dry-Pac mixing instructions.)
- Against a direct flow of water (leakage) or where there is excess moisture due to seepage, use Xypex Patch’n Plug in lieu of Dry-Pac followed by a brush coat of Xypex Concentrate. For expansion joints or chronic moving cracks, flexible materials such as expansion joint sealants should be used.
All areas of poor concrete consolidation (honeycomb or rock pockets) should also be repaired. Refer to Xypex Method Statements (Section 1.3, p. 4-31) or contact Xypex’s Technical Services Department or your local Xypex Technical Services Representative for more information.
Xypex requires a saturated substrate and a dry surface. This is commonly referred to as a saturated surface dry or SSD condition. SSD concrete will not absorb any more water but has no glistening water on the surface. Concrete surfaces, therefore, must be thoroughly saturated with clean water prior to the application so as to aid the proper diffusion of the Xypex chemistry and to ensure the growth of the crystalline formation deep within the pores of the concrete. Remove excess water before the application such that there is no glistening water on the surface. If concrete dries out before application, it must be re-wetted.