CONTRACTORS What follows is a list of things you must know even before the slab for your project is poured, if stained concrete floors are planned for your building. You will need to protect the slab from other trades both before and after staining.
Floor staining usually occurs toward the end of the job, after drywallers and painters, but prior to kitchen counters and toilet installation. Faux Real includes a basic cleaning and spot removal (tar, mastic, paint) in its square-foot price. Drywall mud is fairly easy to remove during our prescrub with a rotary floor buffer. However, paint overspray can be time-consuming to remove, and is easily avoided by having the painters use masking paper and drop cloths.
If there are to be baseboards along the walls, it is a good idea to hold off on their installation until after we have finished the floors. Even though we mask the walls with masking tape and plastic up to 24î the stain can creep through the lower edge of tape. It also wicks up into any endgrain of wood which is in contact with the floor, and turns the wood black.
In the case of plaster or structolite walls which go right to the floor, we must use special precautions and often must touch up small stain spatters on the walls with Kilz or coverstain tinted to match the wall color exactly. For this reason we have a slightly higher price for floors in plastered areas. The plasterers must mask wall edges well during their work, or we will have to wet-sand plaster residue out of the pores of the concrete all along the wall edges before staining. This is quite laborious and also an extra charge which should be avioded.
Warnings and Preparation of Concrete
For Best Staining Results
Do not use any liquid curing compound! 'Monkey's blood,' and anything oily or waxy completely blocks penetration of the acid stain.
Use normal, moderate troweling. Do not allow burnishing with metal trowels. If slab is too smooth the pores are closed and staining becomes spotty.
We advise against using concrete with short reinforcing fibers. The slab ends up looking a bit 'hairy,' usually in clumps. The fibers seem to conduct extra water into the slab after we scrub it, which sometimes causes our sealers to fail in the wet spots unless we give it several days to dry. Construction is often rushed and we don't have the luxury of time.
Let the slab cure for at least two weeks before laying down plastic. We really appreciate having the slab protected from tar and paint spots, but we have found that when plastic is laid down on a wet slab, every crease and fold in the plastic can leave a permanent dark mark on the concrete. The stains are translucent, so every mark in the concrete shows through. Do not worry about rain spots or hail. We have found that these give a natural mottling which adds to the stonelike effect. We are trying to avoid long straight lines which do not look like anything in nature.
When covering the slab, do not use duct tape to hold the covering down. This leaves dark, blocky marks in the concrete which are permanent. Some builders have placed 2x4's along the walls to weight the plastic.
Framer's markings are a real problem for us. The worst thing is red framerís crayon. Even if we sand this off and use paint remover, the arrows and numbers can come back 6 months later right through our stain and sealers. Clients arenít too happy with this in every doorway. Permanent Magic Marker is also almost impossible to remove. The best thing for us is blue or white chalk, with hairspray used as a fixative. Smaller marks are better than large, of course.
Faux Real thanks you for helping us to create an elegant stained floor.
Once the floors are stained and sealed, they should be protected by unrolling walkways' of rosin paper in the main pathways being used by other trades. The paper strips can be fastened together with masking tape, but no tape of any kind should ever be used on a finished floor. When it is removed it can take with it all 4 layers of sealer as well as some of the stain color, leaving a tape-shaped flaw. The paper strips can be weighted down with pieces of 2x4 wood, if necessary. Plastic should never be used, as it can bond with the acrylic sealers and wax and pull them up upon removal.
Image-An architect's residence in Santa Fe, NM. Slab was sawcut into 6'x6' blocks after it had cured before Faux Real stained the floors.