Tips & Helpful Hints on Working with Concrete

How to Add Colour to Your Concrete

A water-based concrete stain is used after concrete is poured and cured. See Sim Stain for colour chart and application instructions.

An acid-based concrete stain is used, which has a chemical reaction with the free lime in concrete after it is poured and cured. Colours available are:

• Cinnamon
• Buckskin
• Coffee
• Moss
• Pike green
• Blue

Acid Staining Preparation & Procedure

1. A quality batch of concrete should consist of at least a 5-sack mix with no fly ash, retarders, curing compounds or chloride accelerators. The slab should be hard trawled by machine to a slick mirror finish. "Burning" the slab creates a nice shading and depth or colour; however, "burrs" or trash caught under the blades cut unfavourable swirls.
2. It is important that the concrete be thoroughly finished with hand tools where needed around the plumbing, risers, floor outlets or any other element which is not accessible by the machine.
3. Silicone chalks should NOT be used if at all possible. The red and yellow chalks are permanent dyes. Do not over mark for the framing. Do NOT use silicone sprays to “hold” the lines. The sprays repel the stain and leave harsh, permanent scars on the floor.
4. It is imperative that wood, sheet goods, sections of framing and the like not lay on the slab for extended periods of time. They can transfer resins and tannins. They alter the moisture content in the slab, which leaves a pattern in the finished floor.
5. The floor should be protected from the following: plumber's glue, foam insulation, bond release agents, flux, oils, grease, polyurethane, paint, markers, grease sticks, spray paints, crayons, muriatic acid, and other chemicals both before and after staining and/or sealing or waxing. Muriatic acid prevents concrete from reacting to the stains and should never be used on concrete that is going to be acid stained!!!
6. The framers should brace the wall to the outside and not to the slab. Doorplates should be cut away immediately.
7. It is extremely important that you do not tape the floor! When covering the floor, overlap sheets of builder's paper from Home Depot. Tape the first sheet to the wall, then overlap the second sheet to the first and tape it to the paper. Do not tape to the floor. Duct tape, masking tape, packaging tape, strap tape, blue tape, green tape and electrical tape – there are NO exceptions. The tape alters the natural curing process and transfers chemicals to and from the slab. This will show in the finished product.
8. When covering the floor, you may use sheets of Masonite® or single-faced cardboard on top of the builder's paper; however, do not cover the floor with plastic at any time! It prevents the slab from breathing, which inhibits proper curing. It can result in efflorescence. Prevent excessive vapor transmission.
9. Touch-ups are often needed and should be expected following a stain, seal and/or wax work.
10. Acid stains are chemically reactive metallic salts that seek out and react with the lime in the concrete. As such, they can be manipulated but not controlled, and anticipated but not guaranteed. Our colour slabs show typical colour reactions. However, every slab is different.
11. Every pour of concrete will react independently to the stains. All elements and circumstances affect the outcome of the floors. Temperature, humidity, age of concrete, batch of stain, batch mix design of concrete, accelerators, fly ash, wind, instructions listed herein and the like will all contribute to the outcome of the floor. Exact colours and stain patterns cannot be achieved – it is fundamental that all parties involved understand this . Please understand also that this process creates a totally unique floor, with depth and beauty that cannot be copied.
12. Cut the slab 1 day after it is poured for control joints and tire or decorative cuts, before the framers set the walls. Then return to stain and wax or seal the slab when the project is "dried in" (framed with doors, windows and water tight – no insulation or sheet rock). After the project is dried in, the floors should be covered as directed above. Should additional wax be needed post-construction, thoroughly clean the floor (sweep, vacuum or mop). An alternate schedule is to wait until the final stage of construction to stain.

Concrete Stamping

• Buff
• Dark brown
• Medium brown
• Blue Grey
• Desert tan
• Green grey
• Brick red
• Plum
• Terra cotta
• Charcoal
• Pink
• Black
• White
• Neutral
• Liquid cherry blast

Installing Paving Stone

• You can check to make sure an area is square by making sure both sets of cross corners measure the exact same distance.
• If you know which type of stone you wish to lay, by a small amount of them and lay them out lengthwise and widthwise to form a cross. Then set your borders to the length of these stones. Using this method may help you avoid unnecessary cutting.

2. Excavation:

The secret of a long-lasting paving stone project lies in a good compacted base for the paving stone to rest on. How thick the base needs to be depends on the soil conditions and the project you are doing. Remove any unstable soil and replace this with a good compacting gravel such as crusher dust. This gravel should have a binder in it such as a bit of clay so that it packs rock hard. We recommend using a pate vibrator or roller and tamp the gravel in 3” – 4” layers. Get your base as level as possible making sure it slopes correctly. The paving stone surface will conform exactly to the base so make sure it is level.

• If conduit or wires are located in the area to be excavated, contact the representatives of the company concerned before the work is started.
• To ensure sufficient drainage, excavate the soil to obtain a minimum incline of 2% (20mm/m – ¼ inch per foot).

• The excavation contour should extend beyond the surface to be paved by at least 300mm (12”). Remove all black dirt until reaching clay. Ideally, this distance should be 1 to 1½ times the thickness of the foundation. The stability of the project depends on this measurement, which ensures that the paving stones at the edge will be as well supported as those in the centre.

Concrete Sealers

Yorkton Concrete currently markets 4 types of sealers suitable for use on concrete flatwork such as driveways, garage pads, sidewalks, and patios. These products are:

• Allied AC309A
• Allied AC309A-HS
• Allied AC 425
• Allied AC 30

Allied AC 309A
A clear modified solvent base acrylic which forms a membrane to reduce intrusion of water, salts and motor oil. This product is effective if properly applied but is affected by UV and wear and should be re-applied every year or so depending on the traffic. This product should not be used as a curing compound on Saskatchewan concrete which is subject to shale popping. Allow 28 days of good curing and drying conditions before applying as a sealer. Used mainly on smooth trowel, broom-finish surfaces.

Allied AC 309A-HS
Same as above but with higher solids content and a higher gloss. This sealer is used mostly on exposed aggregate surface.

Allied AC 425
A Methacrylate sealer with appearance and properties similar to AC 309, but offering more durability. It will provide UV resistance approximately twice as long as an acrylic sealer.

***Acrylic and methacrylate sealers will be slippery when applied to a smooth surface. To improve slip resistance, Z-Lite ceramic spheres can be added at a rate of up to ½kg per 20 liter pail. Mix thoroughly and then apply sealer with a paint roller. Used mainly on exposed aggregate and stampcrete type surfaces.

Allied AC 30
An alkoxysiloxane which penetrates up to 5mm into the concrete depending on porosity and chemically bonds there by reacting with the moisture either present in the substrate or in the atmosphere. This product is very effective against water and salt intrusion. AC 30 is a penetrant and will not wear off, therefore can be considered permanent unless the concrete wears to the depth of penetration. AC 30 will not prevent oil staining. Acrylic sealers may be applied over AC 30 to protect against staining by motor oil. Used on smooth trowel and broom finish surfaces.

Sealers can be very effective in helping to overcome the natural limitations of concrete; however their use will not prevent or overcome the faults of a badly constructed slab due to poor placing, finishing practices or improper design. Since we have no control over these variables, Yorkton Concrete cannot offer any warranty on these products.

Tech Tips
Read even more helpful tips at the Saskatchewan Ready Mix Concrete Association website.