What green sealant do you recommend for the roof of our garage, which we use as a patio during summertime?

Asked by amal
Falls Church, VA

The garage is made of cement. The cement is becoming stained (black color like) from the rain and because it's old. The garage was built in 1964. We see some cracks in the cement, so we need to prevent the water from seeping thru to the garage. What is the best way to do so, and to maintain the cement from getting damaged from the elements? Your assistance is greatly appreciated.


Rick Goyette

Answered by Rick Goyette

Pawtucket, RI

Emerald Dream Builders

July 28, 2012

I have an image of your garage as a bunker-like structure with concrete walls on three sides and a poured ceiling / patio area. Repairing a bunker is a new experience for me; however, in terms of sealing the concrete for your roof/patio this should be pretty straightforward.

Repairing the cracked concrete

Here is a great video that explains which product to use and how to seal each of the cracks which will save me from typing out instructions!  

This should address the cracks you have on your patio and prevent future erosion from the elements and water from leaking into the garage.

Sealing the concrete

The next step is to seal the concrete either with a clear or colored concrete coating but let’s address the topic of a “green sealant” first.

The greatest danger with a concrete sealant would be the impact on air quality in the form of volatile organic compounds. Since your project is outside you have many more options in that regard.

  • Typically I would advise clients to use a low VOC sealant such as Scofield Select Seal W which meets the USGBC’s LEED for Homes Criteria for VOC usage in an area such as an attached garage slab.
  • Since your patio is outdoors the VOC limitations are not as stringent.
  • There are several options available on Schofield’s site here.

Be sure to check the data sheet on the product you use to seal the concrete to ensure it will work well with the material you used to fill the cracks!

Covering the patio

If you are not interested in a color option and don’t like the look of your patio after you’ve sealed it with a clear sealant, you have the option of covering the patio with a wood floor look.

  • There is a product manufactured by an FSC certified organization that can beautify your patio after you’ve filled the cracks and sealed the concrete.
  • Have a look at for a magnificent finish to your project.

Good Luck!


For more information:

Read "I need to stain my concrete pool deck. Are there products and methods you can recommend, other than acid?" a Q&A answered by Cynthia Phakos.

Tagged In: concrete, green sealant

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