How You Can Get Paint to Stick on Concrete — Los Angeles Times

How You Can Get Paint to Stick on Concrete - Los Angeles Times

How You Can Get Paint to Stick on Concrete

QUESTION: How can I get paint to stick to the high-traffic areas on our concrete front porch?

ANSWER: Today’s epoxy, polyurethane and acrylic paints wear much better than oil and alkyd paints on concrete. Before applying a water-resistant paint, clean and roughen the surface. Use a trisodium phosphate solution or strong detergent to scrub the floor. Sanding with coarse emery paper may be required to give the old surface a rough texture for good paint bonding. Test a small area to make sure the new paint will adhere.

And What About Those Musical Floors?

A: Many times, what we call floor squeaks have nothing to do with squeaking floors. Plumbing pipes and heating ducts can pop and crackle, even «squeak» as we walk across the floor.

The easiest way to find a noise source is to have someone walk across the floor while you listen carefully below. Noises that seem to come from heating duct locations can be tracked down and eliminated by loosening brackets that connect the heating ducts to the underside of floor joists to provide a sort of shock absorber between the two units.

Check pipe locations where V-shaped pipe hangers support water or gas pipes hung beneath the floor joists. Joists that flex when they’re walked on can rub against pipes or ducts and create a noise, and ducts that are tied tightly to joists can make a clunking noise or «tin-can» when they bend. Adjust pipe hangers to relieve the noise.

Pipes can also make noises when they expand from hot water, contract from cold water, or vibrate or hammer from high water pressure. Foam pipe insulation can be used to cushion the pipe and muzzle expansion or pressure noises. The insulation will also help prevent condensation from forming on the pipes, which can cause puddles on basement floors. Insulation can also separate pipes from each other to prevent noise from pipes rubbing against each other.

Spacing the Joints on Your New Patio

Q: My existing concrete patio is cracked badly, and I plan to replace it. How far apart should control joints be spaced?

A: Control joints—spaces between one section of concrete and the adjacent sections—relieve stresses in concrete that result from expansion and contraction with changing temperature. They should be spaced a maximum of 10 feet apart.

You can make control joints in three ways: Cut them into partially set concrete with a hand groover masonry tool, cut them into concrete after it has been hardened with a concrete saw or build forms with 1-by-4-inch or 2-by-4-inch strips at joint locations. Strips can be left for decoration.

Ruined Counter Top Can Be Resurfaced

Q: Because of misuse and haphazardness, we have removed the shiny finish from parts of our Formica kitchen counter. The counter is still in good condition, but we’d like to know if we can restore the original finish.

A: Unfortunately, there is no way to restore the shiny finish. The laminate is formed under heat and high pressure—conditions that are impossible to duplicate in the home. Once abraded, the finish can’t be restored. But you can resurface the counter top with new laminate—provided the existing laminate is sound, well bonded and does not have deep texture.

You can call the Formica Corp. at (800) 367-6422 for an instruction sheet on resurfacing laminated assemblies. If you are interested in cleaning and maintaining Formica plastic laminates, ask for the free brochure «Caring for Formica Brand Laminate Surfacing Material.»

Watch for Clay Soil Below Wet Surfaces

Q: I have a painted concrete block retaining wall on the property line with my neighbor. When it rains, excess moisture forms a white powder on the wall, and its paint flakes off. How can I treat my side of the wall to stop the moisture seepage and prevent the paint from flaking? We were advised to tar the wall’s back.

Drains were installed at the wall’s base, but the clay in the soil seems to prevent the water from seeping down to the drains.

A: The white powder on the wall is a mineral deposit that forms when the water carrying the minerals evaporates.

To prevent this, and stop the paint from peeling, you must stop the water from seeping through the wall by installing better drainage. Treating your side of the wall won’t stop the problem.

You are correct in saying that the clay in the soil prevents the water from reaching the drain. Soil with a high clay content does not drain well. This soil should be evacuated from behind the wall and replaced with gravel. A perforated drain pipe should be installed so that water will percolate through to the pipe.

It is important that the pipe have a free-flowing outlet to allow the accumulated water to drain.

Do not simply tar the wall’s back and then backfill with the same soil—the tar will seal the wall and prevent the water in the soil from escaping to the outside.

If the water builds up, it can exert enough pressure on the wall to crack it or heave it.


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