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Robert Lamoureux: Staining concrete is serious business

Your Home Improvements

Posted: April 11, 2009 12:18 a.m.
Updated: April 11, 2009 4:30 a.m.
Mr. Lamoureux,
Several years ago we had a concrete hardscape installed, stamped  and colored (reddish) in a random stone pattern. Contrary to my wishes, the contractor did not mix the color in the truck but put it on top of the wet concrete. After allowing the concrete to cure he then came back and sealed it. About a year and a half later we had him come back and recolor and reseal the hardscape. The problem we are having, aside from the leaching of the calcium on the surface the color is also coming off and leaving blotches of bare grey concrete. My question is what can we do to correct the problem? The original concrete was placed in 2005. Thank you.
Ron W.

Hi Ron,
That’s what happens when the concrete dye is not mixed all the way through. Sometimes the drivers don’t want the mix dyes in their trucks because it’s more work for them to get it off the walls and they don’t want that residue in there.  

Your concrete will continue to have these problems. You can either spot repair, which will be an on-going maintenance issue, or you can strip off the surface and re-stain the entire area. Go to a builder’s supply that specializes in masonry and cement products. They will have all of the products you will need.

If you want to stay with a reddish color, you’ll want to use a water based stain. For the sealer, you can go water base for a natural finish, or you could use a high gloss lacquer that will give you a wet look.

First check that there is no rain in the forecast. You have to remove the existing surface with the appropriate strippers, and make sure that the surface is completely clean and dry before applying the stain. Based on the type of surface you have, they will recommend the best cleaners and strippers. Depending on the size of the area, you may want to use a walk-behind scrubber and a pressure washer.

Follow the manufacturer’s guidelines for the stain application to the letter. People that mix the stains risk serious injuries, which can be fatal.

For the application, wear a respirator, rubber gloves and eye protection. You don’t want to breathe the fumes or let it get on you. You want to scrub the stain into the surface of the concrete with an acid-resistant nylon brush. Only work on sections that you know you will be able to finish that day and try not to overlap because it will be a slightly darker in those areas. Also, be sure and avoid any puddles and don’t step on the wet stain because the footprints will be permanently darker.  

Once the entire surface is stained, allow it to dry for at least 24 hours. They may recommend washing with baking soda and water to neutralize before applying the sealer. Don’t take any shortcuts and do what they suggest.  

Allow the sealer to dry for 24 hours before walking and 72 hours before driving. Then follow the maintenance schedule. Depending on the types of products you use, they usually recommend re-sealing once every year.

Hello Robert,
I want to install some lighting on both sides of my driveway and sidewalk. I looked at some fixtures and don’t know if I should go low voltage or high voltage. I’d like to get your opinion on the difference. Thank you.
Ralph V.

Hi Ralph,
Personally I like the high voltage. Many people are familiar with the low voltage Malibu lights. These are very popular but any perceived savings on lower electrical costs is outweighed by continuous repair and maintenance.  

One of the problems with low voltage fixtures is the minute you have any condensation — when the fixture sweats inside because of temperature changes, it will drip internally onto the contact which will corrode and won’t light. When this happens you either have to replace the contacts and bulb or replace the fixture. This becomes a constant maintenance headache.

High voltage fixtures have the same condensation problems, but the current is stronger so it will arc over the corrosion and keep the light illuminated. They also provide more lumens so you don’t need as many to provide a greater amount of light.

The other side of this is that some cities require you to place high voltage electrical lines two feet underground, whereas low voltage cabling only needs to be six inches deep.  Depending on the length of the run, high voltage would require a lot of trenching to place the lines. This would be more expensive up front, but will save you money and a lot of aggravation in the long run.

Your Home Improvements,
I replaced a heater timer to a spa but it still runs after it’s off. I’m sure I wired it right because it is heating, but why is it still running? Thank you.
Raphael G.

Hi Raphael,
There’s a secondary switch, a trip switch that allows an additional run time of usually 20 minutes. This re-circulates the water from the spa, without the ignition being on, to cool the manifolds down. If you slowly let them cool, instead of an immediate shut down, they have a less likelihood of cracking the manifolds.  

After 20 minutes, that switch will trip and turn off the system.  

Hello Robert,
We have a brick planter that is always getting hit by cars as they pull in too close to our business. I’ve noticed that there are pipes in front of gas pumps that I think would work well for us. How do you put these in?  Thank you,
Natalie B.

Hi Natalie,
Yes, those would work.  They’re called bollards. Don’t use galvanized pipe because it’s not strong enough. Go to a metal supply house and get “black pipe.” This is the same pipe they use in fire sprinkler systems and is very strong. You want to get a minimum of three inches, and ideally a four inch diameter with one quarter inch wall.     

Break out the asphalt or concrete and dig down enough to dump at least 800 lbs. of concrete underground. Set the pipe, fill with concrete with a nice round cap on top. Then paint it traffic yellow or use one of the traffic colors.  

Unless you own your building, you should check with the Board or property owner before making any types of improvements. Once you get approval, you then need to call Dig Alert at 811 before digging. Any time earth is moved, it doesn’t matter if it’s only a couple of inches, Dig Alert needs to be contacted beforehand. If not, you could be fined as much as $50,000.  

Once notified, they will come out and mark whatever utilities you may have running underground — fiber optics, phones, electrical, gas, water or sewer. The service is free.  

If there are utilities present, they will mark what kind there are and where but not the depth. You would then need to contact that particular utility company and ask about the protocol for pouring concrete around their utility lines in your city. If you get the green light, you have to hand dig 24 inches on either side of the utilities, and proceed with caution to not cut or even nick those lines.  

Robert Lamoureux has 25 years experience as a general contractor, with separate licenses in electrical and plumbing contacting. He owns IMS Construction Inc. in Valencia. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor, after that contractor has made a thorough visual inspection. Send your questions to


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