If you're wondering, "do I need to prime before tiling?", the answer is generally yes.
Do I need to use a primer? Yes, with the exception of substrates covered with a waterproofing membrane due to its non-absorbent nature. We recommend the use of a primer on all other substrates to be tiled. By not using a primer, you can void your product and tiling system warranties.
In conclusion, you can tile straight onto waterproofing provided the surface is non-porous and smooth. If you are tiling onto a porous surface, such as concrete, make sure to seal it first. And if you are tiling onto a rough surface, such as brick, make sure to smooth it out first.
No wait time is required. A water test should be performed before setting tile to verify a successful waterproofing installation. This evaluation may be required by building code officials and is considered best practice.
The product is dry when it turns solid red with no pink showing, normally 1-1/2 to 2 hours. Depending on ambient conditions, drying time can take up to 12 hours. A water test can be conducted 72 hours after application if required. Clean tools and hands with water before material dries.
For tile installations bonding directly to the substrate; strongly recommended to apply at least one full coat of "undiluted" RedGard® to the "dry" primed area and allow to dry completely before tile installation work is to begin. When used as a vapor barrier, apply one full coat (70 sq. ft.
Mapelastic AquaDefense is ready to receive thin-set mortars for tile or stone when dry to touch (about 30 to 50 minutes after applying second coat).
Wet Rooms And Bathrooms
If you're waterproofing a bathroom, count on it taking 24 to 72 hours to dry. If you can, try turning on any fans or opening windows as soon as possible to ensure good ventilation. Do what you can to keep the area well ventilated while the drying process is underway.
CUSTOM®'s R&D lab has tested and found that a continuous single coat of RedGard® is sufficient to waterproof WonderBoard® Lite cement backerboard-covered walls for shower application in order to meet building code requirements.
APPLICATION OF THE PRODUCT Mapelastic AquaDefense must be applied in two even coats (minimum 0.4 mm wet film thickness per coat) with a long-haired roller, brush or trowel.
Can You Waterproof Over Old Waterproofing? While it technically is possible to waterproof over existing waterproofing, it is not something we would recommend. Alternatively, we recommend you invest in remedial waterproofing such as that we offer at Remedial Property Solutions.
Substrates like plaster, drywall, and cement board used in tiling need priming to create an ideal base for tile adhesion. Such substrates are porous and can absorb moisture from the tile adhesive, potentially weakening the bond and leading to tile failure.
Water-resistant.
Once cured, thinset is more water-resistant than mastic or other tile adhesives. With the right additives, thinset can be chemical-resistant, making it a good choice for commercial or industrial tile applications as well.
The surface can be cleaned and waterproofed with a suitable damp proof membrane or epoxy coating. Tiles can then be installed over the waterproofing when it is fully dried using a suitable waterproof adhesive.
If you have completed a project without using primer, there's a good chance the membrane will not adhere properly to the substrate. This means you will need to redo all of the work and purchase new materials. A a primer is an inexpensive and important 1st step in the complete waterproofing process.
Should plasterboard be primed? Yes, apply an acrylic based primer such as BAL Primer (undiluted) to the plasterboard with a brush or roller and leave to dry before applying any powered adhesives. All board joints and internal corners should be reinforced using a suitable alkaline joint tape before tiling.
Ambient and surface temperatures must be above 40°F (4°C) at time of installation and for 72 hours after application. Tile over membrane within 72 hours in exterior applications to avoid extended exposure to ultraviolet rays.
Most water-based membranes require a final application rate of approximately 1.5L per per square meter. This is often achieved with two coats, however, as application techniques and membrane viscosity vary, you may need to put on further coats to achieve that type of usage.
Apply a Waterproof Membrane:
To provide an extra layer of protection, it's advisable to apply a waterproof membrane on the entire surface that will be tiled. This membrane serves as a barrier against water penetration and helps prevent any potential leaks.
Next, apply a surface primer with a broom, brush or roller to all areas that are being waterproofed. Start with the walls in the back corner, work your way around and then complete the floor. Once done, allow the primer to dry – this should take about an hour, depending on the chosen product.
Wind, airflows, humidity, fog, snow and rain all have their own issues when it comes to using liquid membranes and can severely affect the future performance of the applied waterproofing coat. Water falling onto waterborne and cement-based membranes can mean they don't dry properly and potentially can be washed away.
Once your room has been waterproofed and left to cure for 24 hours, the tiling process begins.
Which thin-set mortar should I use over waterproofing membranes such as Mapelastic AquaDefense and Mapelastic HPG? The thin-set mortars recommended for waterproofing membranes are polymer-modified thin-set mortars. Do not use mastics such as Type 1 or Ultramastic ECO on waterproofing membranes.
While the membrane protects against water penetration into your home's foundation, it also works as an adhesive surface for the primer and paints you'll use to finish your project. So yes, you can paint over the waterproofing membrane!