Priming basement floors and walls

Basements and cellars are often somewhat stuffy and damp spaces. This is often because the floor and walls allow moisture to penetrate. To give the floor and wall a waterproof layer, a good quality primer must be applied, after which an epoxy coating can be applied. This will stop moisture penetration, making the climate in the basement or cellar much drier and making it suitable for storing tools, food, etc. But of course it can also be furnished as a hobby room, bedroom or other living space.

The preparations for renovating your basement or cellar 

First remove all loose layers from walls and floor. These are often layers of paint, loose plasterwork, cement, etc. If any parts are still stuck, see if they can be removed with appropriate force. It is very important that the surface is of good quality. After removing everything that could cause problems, clean everything thoroughly and make it dust-free. You can now see which repairs are necessary to make the basement floor and wall waterproof and smooth.

Below you will see one of the most common basement floor problems and how to fix it.

Repair exposed and rusted rebar with epoxy

Exposed and rusted rebar should be examined carefully. If the amount of rust is not too bad, the damage must be painted with epoxy primer for damp surfaces or, if the surface is thoroughly dry, with epoxy primer for dry surfaces.

A mortar can then be made with universal epoxy, thickened with Stewathix or even dry sand, to supplement the missing concrete or masonry. If necessary, do this in parts or use a wooden plank covered with packaging tape to serve as temporary formwork. In this way, the rebar is newly wrapped and the strength is restored to the construction.

Supplies:

• Universal epoxy with fast hardener
• Stewathix

Repair cracks in concrete with epoxy

Shrinkage cracks or cracks often arise due to action along the transition from floor to wall or where construction parts have been made in the floor or wall. Small cracks can be filled by brushing epoxy over the crack several times. Slightly larger cracks, especially in the floor, can be filled by drilling an 8mm hole into the crack every 10cm. Dust the holes and fill them with universal epoxy. This will then fill the crack. It is often necessary to fill the holes several times.

Stubborn cracks can be provided with a glass fiber tape with epoxy resin after filling with epoxy to obtain a better crack-bridging construction. This prevents the crack from recurring in the later finish.

Supplies:

• Universal epoxy with fast hardener
• Glass fabric tape

Applying the epoxy primer in the basement or cellar 

Sometimes a corner or a certain spot in the basement or cellar won't dry or it dries more slowly than other places. Try to ventilate the area to dry. If that doesn't work, let a fan heater blow on the area for a few hours. The area is then often temporarily dry, giving us the opportunity to apply epoxy.

Apply an epoxy primer for damp surfaces to walls and floors. To do this, mix the basic component with the hardener. Mix this well and use a spiral mixer in a drill. Then apply the epoxy primer with a roller or brush. First use a brush to prime the edges and difficult corners with epoxy primer. Then pour the primer in a strip over the floor and spread it with the roller. Roll out the epoxy primer evenly and roll crosswise. Then do the next strip. Repeat this until the entire basement is primed. Keep an eye on the processing time of the epoxy as you work. In particular, larger amounts of epoxy in a bucket can cure faster than expected (even faster than the stated working time) so spread the epoxy over the floor fairly quickly. Once on the floor, the epoxy will cure more slowly. If the floor is too large or has a lot of brush work, ask someone to help. This way, 1 person can paint brushes and 1 person can roll at the same time.

Once the primer has hardened, usually the next day, areas where the primer has completely penetrated the substrate can be primed again.

Supplies:

• Epoxy primer for damp surfaces (approx. 250 gr/m2 per layer)
• Fleece rollers (18 or 25 cm width)

Follow up

Depending on your wishes, the cellar can now be further processed in various ways. In the event of serious moisture penetration, it may be wise to apply a glass fiber covering to the affected floor or wall. You can consult the following manual for this:

Waterproofing walls and floors

An epoxy coating can be applied to the glass fabric or directly to the primer. Once this coating has hardened, the basement is waterproof and will be more usable for, for example, a sleeping area, storage of supplies, hobby room, etc. You can read more about applying an epoxy floor coating here:

Finishing the floor with epoxy floor coating