Resealing concrete - plain and exposed aggregate?

[deerminator]

Looking for any tips on cleaning and prep before I go ahead and do it. I recently stopped by a big box store and bought a couple gallons of wet look sealer for our exposed aggregate patio (16x16), which is starting to look a little dry. And I bought a 5 gallon bucket for our 26x28 plain concrete parking pad+small adjacent sidewalk. I purchased rollers and various supplies to apply it per our builder's direction.

Anyway, rambling here, but our builder told us we should really only need to reseal both every two years - which it has been now since I had them poured and finished. When I was at the store, however, another customer got after me saying you need to reseal exposed aggregate every year, end of story. He then told me that since I've waited so long, I need to clean it first with some muratic acid mixed with water (which I have for our instant set pool btw to lower alkalinity when needed). I told him I had planned on pressure washing both the aggregate and plain concrete and he said absolutely not to do that since it would leave streaks? I've pressure washed both before and never had any issues. I've always used a low pressure on the aggregate for fear I might knock some of it loose.

Anyway, any tips on prepping and sealing recommended! Thanks!

[Shack]

Is their any stains or discoloring?

The manufacturer of the sealing product should provide detailed instructions for prep. I would not use any acids on the agg. unless you have heavy stains from hard water or grease/oils. The acid removes the top parts of the surface. I would use it as a last resort for cleaning with exposed.

If it were I, I would wet down the patio with a hose. Use a bucket filled with hot water and an outdoors degreaser cleaner, brush it in with a broom and then use the pressure washer. Let it dry good but not too long as to let dirt blow back on the area. It still is a good idea to use a dry, clean broom to sweep and if possible an air comp. to blow off the surface right before you apply to coat. Make sir you over lap your roll's when putting it down. When using a roller, approach it as you would with painting walls. Have brush handy and hit any corners or hard to get spots first with the brush. Mask off any surfaces you do not want to get the sealer on. It will show. Two coats is about the norm to make sure it is covered. I do about 3-4 to give it a thick coating.

As far as when & how often to coat depends on the situation. Direct contact with sun and weather is a factor. Heavy traffic, person preference on looks, stains, salt use, brand of sealer used and how many top coats applied will play into how often you should reseal. I have had good luck with going by a year for every coat applied. I do mine about every 3-4 years. When you are talking about high gloss and keeping the look, then it's when it starts to dull. Just cause the gloss fades does not mean the sealing properties fade also.

As far as the non-exposed goes, if you want brighten it up or remove heavy stains, bleach has always been a great tool for me. I apply it on a full sun day, with a long handled cleaning brush, with hot water & bleach in a bucket. Depending on how you mixed up the bleach & water, I just let it sit on the concrete in the sun until it dries. Then I use a pressure washer to rinse and them clean the concrete. Remeber plants and stuff you do not want the bleach to get on. For heavy stains I will apply straight bleach to just that area with try best to blend it in to the surrounding non stained area. I reapply until the stain is reduced to a point I like or gone. Brush the bleach in every 5 minutes or so until dry. The same can be said about the entire slab and using a mixture of water & bleach. Keep doing it until the desired look you want is had.

I have not tried it but I am sure bleach would brighten up the exposed also. Most people like the deep rich look with exposed and it could whitening is the reds & browns. A heavy diluted mixture could prevent this.

Good luck.

[deerminator]

Thanks very much for the ideas. I'll look into the degreaser for the exposed and the bleach for the plain. I don't really have many stains on either - just a tiny faded oil spot on the plain and a rust spot here and there on both surfaces. Mainly the concrete is just really dirty on the parking pad/sidwalk out front since we have a class 5 gravel driveway and have been doing lots of landscaping around it.

I read that brushing arm and hammer powdered laundry detergent against the concrete could work well to remove rust and oil spots. I haven't tried it on the stains yet but did just try it out on an area of plain concrete today. It really cleaned it well. I wonder if oxyclean wouldn't work well for that too? I have a big bucket of the powder sitting around. I may check into that.

Regardless, I think I'll stay away from the acid and give it a good cleaning, erring on the side of caution. Think I'll stay away from the bleach or anything with it on the exposed aggregate. Worst case is it looks a little darker if I can't get it as clean, which is what I'm going for anyway. Thanks again.