Patio Problems

[machmeter62]

We have been renting a home to others for the last 27 yrs. The home has been vacant for the last year, because of up-grading the home's interior to rent again. There has been a "fungus/moss" that has embedded an outside concrete slab that we want to cover this patio there with tile or a stone finish?

We have tried various product to remove this problem without success...including products that were recommended. The embedded moss is bounded by tiny black roots, that can only be removed sofar with a wire brush. We have also tried products from Lowe's/ Home Depot. Our next attempt will include soaking the slab in clorox, followed with a pressure-washing method?

Would swimming pool chlorine work, or is it the same as clorox? Would boiling hot water work, or is this a waste of time?

Thanks in advance for any other ideas!


Thanks for any future suggestions.

 

[CurlyDave]

Liquid swimming pool chlorine is the same chemical as Clorox, but about twice as concentrated.

The last time I looked at this was maybe 20 years ago, but back then it was just a little bit less expensive to get the swimming pool chlorine. But for small jobs, the expense was offset by the inconvenience of the pool chlorine coming in returnable bottles, while the Clorox was in a disposable bottle.

For hot tub, Clorox was overall better, for a large swimming pool the pool chlorine was more economical.

 

[Eyeshade]

Moss kill or something with a metal content, iron, zins. Then powerwash.

 

[Gary Fowler]

I would think that if you are going to cover it with concrete or stone, just a good High Pressure powerwash will remove the moss and roots. Covering it would prevent regrowth. If you wanted to double dose it, power wash then pour full strength Clorox into the cracks and let it set. Sunlight will remove by oxidizing the chlorine out and only water will remain after a few hours. You could then just put your topping on.

 

[Gary Fowler]

I just pulled this off MSDS sheet from internet so be carefull what you mix with whatever you have used before.

"There are two main types of chlorinating agents:

inorganic chlorinating agents such as calcium hypochlorite, lithium hypochlorite, sodium hypochlorite, and
organic chlorinating agents such as trichloroisocyanuric acid, potassium dichloroisocyanurate, sodium dichlorocyanurate [as anhydrous or dihydrate forms].
Organic and inorganic chlorinating agents are not compatible with each other. Many incidents occur when the same scoop or pail is used for both chemicals with out cleaning them or when adding one product after the other or in the pool chlorinator. Mixing or cross-contamination of these chemicals can form an explosive mixture. "

 

[tcartwri]

Tiger torch, wait a few days, then pressure wash.

 

[Egon]

Caustic soda should work and then the power wash.

The soda should remove any organic materials. If it is used follow safety precautions.

 

[Eyeshade]

I think they use muriatic acid to clean concrete. Be careful as it will remove a fine layer of the finish but you are going to cover it anyway.

 

[Western]

I think they use muriatic acid to clean concrete. Be careful as it will remove a fine layer of the finish but you are going to cover it anyway.

This is what my Grandfathers company uses prior to putting down resin surface's on concrete. Hydrochloric Acid too

Works great and etches the surface to help with bonding. Make sure if you use it, that you rinse it well and any exposed metal close by that the vapor reaches.

What we do is , pour on, use a sacrificial bristle brush type broom, scrub surface. Wait 10 min or so, rinse with hose then pressure wash. You can just pressure wash, but its messy and blows the stuff every where. rinse very well.

Concrete should look like new, with a grit surface.

wear a respirator or "hanky", the visible vapor, (looks like steam) makes it hard to breath and you want as little as possible.

Not nearly as hard as it sounds.

 

[EddieWalker]

Regular laundry bleach is highly diluted and just about at the lowest end of what you can buy. There is an outdoor bleach that is much stronger and it does a great job of killing moss and anything else growing on a house. It comes in a bottle similar to laundry Clorox, but the label is green. Home Deopot and Lowes both sell it.

For really strong bleach, liquid swimming pool shock is about the strongest concentration of bleach that you can get. It will make your eyes water and desovles your clothes if you get any of it on there. It will kill and clean like nothing else. It will also burn and can be dangerous if you use too much of it in an enclosed space. An outside porch would be perfect for it. Spray it on, and let it do its thing. I wouldn't rinse it or do anything for at least 24 hours.

Walmart and Lowes both sell it in their pool sections. It's not very expensive and I forget who is cheaper. For as little as I use it, I've never compared prices.

Be careful with a power washer around the house. They are great for walkways, but the very worse thing that you can ever do for a house. NEVER spray your house with a pressure washer. All you are doing is forcing water in where it is not supposed to go, and damaging the caulking, mortar and paint that is probably perfectly fine on your house right now. Nothing on your house is designed to handle that kind of pressure, just rain water and wind. Forcing water into the cracks and joints of your house will lead to mold and rot. There is nowhere for the water to go, and it will take months to dry out under some conditions. There is no advantage to doing this, and a lot of reasons not to.

To clean the house, spray it with a quality house cleaning product using a garden hand pump sprayer. I like Jomax from Zinsser, but have heard of other brands that work well also. Let it sit for an hour or so, then wash it off with the garden hose. The results are impressive. I do this for realtors wanting to prep a house for sale all the time.

Eddie