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Robert Lamoureux: Pass on this 'injection' for waterproofing

Your Home Improvements

Posted: January 9, 2009 9:10 p.m.
Updated: January 10, 2009 4:59 a.m.
Robert Lamoureux Robert Lamoureux
Robert Lamoureux
Hello Mr. Lamoureux,
We have planters that are leaking into units and the subterranean parking structure. We called a contractor and he recommended "injection." I wanted to get your opinion of this as we want to correct this problem.
Silvia D.

Hi Silvia,
I don't believe in injections because they have a bad failure rate. In my experience, it becomes an ongoing maintenance issue as they are constantly coming back for more injections. Not that I have been involved with it, but I have been around it and I am not aware of any cases where the injection solved the problem. The premise behind injection is that it coats the walls and/or ground with a waterproofing agent, but it only works in spots and does not cover the entire surface. Personally, I would not tie my name in any way to injections.

Another waterproofing method I do not recommend is what we call a negative waterproof. This is where the contractor would apply Xypex or DryLoc to the exposed wall that has water coming through it. This is usually the least expensive option, and it will seal that wall, but you still have water seeping into the wall from the other side that is deteriorating the steel and the block. Concrete and block are not designed for constant water exposure. Eventually, the wall will spall - where chunks of concrete will chip off, and ultimately if the problem is not addressed, you could run the risk of collapse. A lot of people think that if they don't see the water, then everything is fine but it's not. The water is still seeping into the wall from the other side and is being held there from the Xypex or DryLoc.

The right way would be what we call positive waterproofing. In your case, first we would excavate the planter and remove the existing waterproofing product, if any, and then apply bituathane with amacore board. This way, we are basically turning the planter into a water tight container. We also would install an underground water drainage system, a leech bed, and surface drains that would allow any accumulation of water to run out and away from the building. This is how it's done. Do it once, do it right.

Dear Robert,
We have trip hazards on our property. Grinding is cheaper than replacing the concrete, true? If so, why would anyone choose to replace.

Hi B.D.,
Yes, grinding is cheaper than replacement, but it is just an inexpensive and unsightly band-aid.

Grinding is fast. You come in and grind down the lifted areas of the concrete. When finished, you usually have visible grind marks as well as the exposed aggregate. Although you have taken care of the trip hazard liability, this is only temporary. Why did the concrete lift in the first place? Usually it is because of roots that lift a section or because of soil that has sunk. With grinding, these problems are not addressed so it's just a matter of time before the conditions return.

To R & R - remove and replace the concrete is much more labor intensive so it is more expensive. First we saw cut through the concrete, if necessary, to have a clean demo - use a demolition or jack hammer to break out that section of concrete. Then we remove the old concrete and dispose, drill holes to pin with steel to hold the new pour in place, remove any roots or add and compact the soil as necessary, re-form, mix, re-pour and then finish to existing. All of these steps require much more time than grinding, but if it's within your budget, this is absolutely the right way to repair trip hazards.

Hi Robert,
I am working on a project around the house and would like to install a secret door. And I can't find any locks that are hidden, they would all be visible after installed. Do they make hidden locks? If not, how could I hide the locks?
Ernie G.

Hi Ernie,
There is a lock called a Tot Lock, a child-proof lock that would be hidden from view after the install. It operates with a magnet. You would drag the magnet across where the latch is located that would open or secure the door.

Dear Robert,
We have a problem. We have a property in Santa Monica that is leaking. We had repaired this problem three years ago and now it's just as bad as it was before. Basically, we had an elastomeric deck that was cracked and in bad shape. The contractor suggested instead of replacing the deck, to cover the old surface with tiles that would act as a water barrier. Now it's leaking again. We put in Mexican Pavers. What type of tile would last longer?
Soaked in Santa Monica

Hi Soaked,
Forget about the tiles. They are the problem. You cannot place anything like that on top of a decking system. When the elastomeric first failed, that was the time to pull it up and replace it with a new deck - preferably fiberglass.

The contractor should have known better than to cover it with those tiles, which are porous anyway. With the humidity of the ocean, the morning dew and water from cleaning and rains, the water traveled between the tiles and the already bad deck and sat there. Then with heat from the sun, you get a pressure pot effect. The decking popped and let the water into your home.

What needs to be done now is rip out those pavers and the old deck and start from scratch. You'll probably need a new subfloor and maybe new joists as well. Water will rot wood, so check the condition of any of the framing once you get the subfloor pulled.

If the joists only have 25 percent or less damage, you can come in and sister - or nail a new joist beside it, instead of replacing. When sistering, you can either lag them together or do a bolt through with nuts and washers. Depending on the condition, you can also place a new joist on each side. If you try to take the joist out, it's nailed into the plywood it will cause more damage than to sister one or two joists on each side. That will be at the discretion of the contractor.

You also need to get all of that wet drywall out of there as soon as possible and use dryers and dehumidifiers to help prevent against mold. If you see any indication of mold, stop and take care of that immediately. If you do this yourself, remember this is dangerous stuff. Wear respirators and gloves. There is a product called SporiClean that will eliminate mold on contact, but I would recommend using professionals.

If you do see mold, it's critical that you do not turn on any fans or dryers because they will blow those spores all over the house.

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 His opinions are his own and not necessarily those of The Signal.


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