Concrete patio stabilization

[Ashful]

One of our patios is concrete, with a pea pebble surface. It was installed ca.1994, and just in the last year has started to show a few hairline cracks. At the moment, they're only noticeable when you really look for them, or after a rain. They stay wet a while, when the rest of the patio has already dried. Seeing how they soak up the water, I imagine that if left alone, it's only a short matter of time before these hairline cracks blow wide open due to winter weather.

In addition to this, the patio seems to get dirty pretty quick. Pressure wash it in April, and it's already showing staining and dirt by July. It seems the concrete has become porous, as if the previous owner had used salt on it in winter.

I imagine there is a sealer that will solve both problems, since I've caught these cracks in the hairline stage. Advice?

 

[pyroholic]

One of our patios is concrete, with a pea pebble surface. It was installed ca.1994, and just in the last year has started to show a few hairline cracks. At the moment, they're only noticeable when you really look for them, or after a rain. They stay wet a while, when the rest of the patio has already dried. Seeing how they soak up the water, I imagine that if left alone, it's only a short matter of time before these hairline cracks blow wide open due to winter weather.

In addition to this, the patio seems to get dirty pretty quick. Pressure wash it in April, and it's already showing staining and dirt by July. It seems the concrete has become porous, as if the previous owner had used salt on it in winter.

I imagine there is a sealer that will solve both problems, since I've caught these cracks in the hairline stage. Advice?

View attachment 105288 View attachment 105287

No advice, but that is a great looking patio!

 

[lukem]

I would definitely put some sealer on it. The freeze/thaw cycle is going to start to open those cracks up more and more every year. I find the box store sealer to be a waste of time. I usually go to a contractor supply store and get some... but I'll be damned if I can remember the name of it right now...I think it is a brand specific to the store (Jobsite). I seal my in-laws pool area with it every year.

They say there are two types of concrete...that which is cracked....and that will crack. Just have to stay on top of it before the cracks get too big.

 

[semipro]

For the cracks I suggest something like this if you can get it flow in. I've used it in control joints in exterior conctrete and it holds up very well.
http://www.quikrete.com/productlines/PolyurethaneConcreteCrackSealantPro.asp
For the surface spalling I'd suggest there's a sealant out there that would help but I've not used one. Do a search on "concrete spalling".

 

[Ashful]

Thanks, guys! Just to be clear on the cracks, though... there's nothing to fill, yet. You almost can't even see the cracks, until the patio gets wet. During the dry cycle, there's a period where the rest of the patio dries off, and the area around each crack stays wet a few hours longer. That's how I first noticed them.

 

[lukem]

Is that exposed aggregate or dyed and stamped? Hard for me to tell from the picture. Either way, get some good quality sealer. If there's no texture to the concrete then you might want to add some silica to the sealer otherwise it could get mighty slippery when wet.

 

[mywaynow]

Sealant should work well on hairline cracks. Take note of the overall patterns though. If you see lengths of small or continuous cracks in one direction, you may want to cut relief seams and fill them with caulk. Otherwise ugly, uneven cracks are in the future.

 

[semipro]

Sealant should work well on hairline cracks. Take note of the overall patterns though. If you see lengths of small or continuous cracks in one direction, you may want to cut relief seams and fill them with caulk. Otherwise ugly, uneven cracks are in the future.

2nd this. Its hard to tell but it doesn't appear that there are any control (expansion) joints in that rather large slab.
You can ward off future random cracking by doing as MWN suggests.
I created control joints in my last slab using a diamond blade in a circular saw and then filling with the polyurethane sealer I linked to above.

 

[Ashful]

Thanks, guys. There is one control joint in the slab, which runs directly under the table for 6 with the umbrella. The cracks are mostly running in the area near the 4" PVC drain to the right of the table, toward the fireplace. I'll try to get a photo when wet, which shouldn't be any trouble with the weather we're having this week!

 

[mywaynow]

That drain is a weak point for the surrounding area. It could also be the source of settling if there is a leak, or the drain is not piped away. Beautiful patio there! Have the new tax rates hit you and your patio yet?

 

[Ashful]

New tax rates?

We have about a million miles of drain pipes, and I tracked these ones down to the wetlands about 400 feet away. Straight shot, 4" dumped along with a few others into 6".

 

[ScotO]

Joful, look for a Siloxane-based sealant. It's silicon sealant, goes on looking like skim milk but dries crystal clear with NO sheen to it at all......looks natural after dry. I used that on my stone chase, and it's amazing stuff. They recommend you re-seal it ever 3 or so years for optimum performance. It's almost weird seeing it work. The stone looks normal until rain hits it......then the rain beads up like there is a coat of wax on the stone.....

(broken link removed to http://www.prosoco.com/Products/%7BD113DB5A-0836-4C51-822E-B0006E080476%7D)

 

[Ashful]

Cool. I've used siloxane on stone walls, but never on a walking surface. Will need to read up on this a little!