Q: Can You Seal Old Concrete
A: Yes! Old concrete can be sealed for the first time or resealed if it has been previously sealed with a concrete sealer. Before sealing old concrete you want to make sure you determine if the concrete has been previously sealed. If a previous sealer has been used you want to make sure it is removed by acid etching or grinding. If the previous sealer is compatible you may be able to reseal without removing the previous sealer. (Solvent based acrylic concrete sealers can be applied on top of previous solvent based acrylics).
Once a previous sealer has been removed you are then going to want to clean the concrete. You want to make sure all mold, mildew, efflorescence, rust, grease and oil are removed from the concrete before sealing as you do not want to seal these elements into the concrete. If you are applying an epoxy floor coating you are going to want to make sure you have good surface profile which can be achieved by acid etching or grinding the concrete.
Since old concrete may have developed cracks throughout the years, you are going to want to make sure all cracks are filled. SikaFlex provides great crack repair products available in different colors to match any concrete substrate. If the concrete has extreme damage from spalling or pitting you may want to think about using a concrete overlay to resurface the existing concrete and then preventatively seal. Concrete overlays are essentially thin layers of concrete that is mixed up and applied on top of an existing slab.
Once the concrete is properly prepared you can then go about sealing the concrete. When choosing a concrete sealer determine the type of protection you are looking for before choosing a product. If you are looking to seal a driveway from road salts, use a penetrating salt repellent sealer. If you are looking to seal a basement from moisture use a waterproofing concrete coating.
What is the best concrete countertop wax? When it comes to protecting concrete countertops you are going to want to choose either a durable concrete coating, or a penetrating concrete sealer and wax combination. Durable concrete coatings are great for heavy spills, heavy duty cleaners, abrasion resistance and high gloss finishes. If you want to protect your countertop and completely stop the penetration of spills and staining use a coating.
If you are looking for the concrete countertop to retain its natural look use a penetrating concrete sealer. Penetrating concrete countertop sealers will help to inhibit the penetration of water and staining from fluids. Keep in mind that spills still need to be cleaned up in a timely manner when using a penetrating concrete countertop sealer. Using a concrete countertop wax in addition to a penetrating concrete sealer will help to increase the staining protection, and bring the sheen up to a satin finish.
We like this concrete countertop wax, it is a food safe blend of beeswax, carnauba wax and mineral oil that is specifically manufactured for concrete countertop applications. A few light coats of wax is applied to a concrete countertop and we recommend waxing the countertops weekly. Concrete countertop wax is extremely affordable and provides much needed added protection to penetrating concrete countertop sealers.
Q: How often do you have to seal stamped concrete?
A: Stamped concrete is concrete that is textured and/or patterned to resemble stone, brick, flagstone etc. It can be colored using a stain, dye or integrally colored with pigments. If the stamped concrete has been colored a lot of times a sealer will be used to enhance the colors, patterns and the textures. Solvent based acrylics are popular choices to seal stamped concrete. Solvent based acrylic concrete sealers are topical in nature so they need to be reapplied every year to every few years. This can be extended if deicing salts are not used on the surface.
If a stamped concrete sealer is used around a pool deck it will usually need to be resealed every season. This is because the chemicals in the water or the salts in the pool water will wear away at the coating over time. The water will sit on the stamped concrete and break down the sealer. The good news is that the sealer is taking all of the abuse which means that the stamped concrete itself remains protected and in tact.
Solvent based acrylic concrete sealers will last longer than water based acrylic concrete sealers. Solvent based sealers will also provide a deeper enhancement and gloss. Additives can be mixed into solvent based acrylic sealers to bring down the sheen and non slip additives can be mixed into for added traction especially around pool decks. Water based acrylic concrete sealers will leave a lower sheen and do not provide as much color enhancement. They are less slippery when wet and are ideal for states with VOC restrictions.
Penetrating concrete sealers on the other hand do not provide any enhancement to the stamped concrete; however, they are able to last much longer. The stamped concrete will retain its natural appearance without any gloss or sheen but the penetrating concrete sealer will protect from spalling, cracking and mold for up to ten years before needing to be resealed. The sacrifice of using a penetrating concrete sealer on stamped concrete would be the clear, natural finish and the lack of sheen or gloss.
Q: How Many Square Feet Does Concrete Sealer Cover
A: Square footage is going to depending on a number of factors including what type of concrete sealer you are using, the surface profile of the concrete and how many coats of concrete sealer you are applying.
Penetrating concrete sealers do just as their name implies, they penetrate deep into the concrete providing protection from the inside out. Penetrating concrete sealers do not leave a surface film and they do not provide any enhancement. They do; however, go a long way. Penetrating concrete sealers have a watery consistency, a lot of times because their viscosity is very close to water on the centipoise scale. Penetrating concrete sealers will typically cover anywhere from 100 – 400 square feet per gallon. Two coats are usually recommended so this will cut the coverage amount in half to 50 – 200 square feet per gallon for 2 coats.
Concrete coatings, epoxy floor coatings and urethane coatings have a thicker viscosity and the coverage rate will vary based on the mils (one thousandth of an inch) thickness they are applied at. Some durable concrete coatings are applied over 20 mils in thickness and would constitute a high build system where as some durable coatings are applied at 5 mils in thickness which would constitute a thin build system. You can get anywhere from 100-600 square feet per gallon out of a durable coating. You usually apply one coat of primer and one coat of topcoat.
Decorative concrete sealers and coatings are usually applied in a single coat with the square footage per gallon varying depending on the porosity and substrate and if the concrete has been previously sealed. For example, pavers are going to be a lot more porous than hand troweled concrete and the square footage per gallon of sealer is not going to go as far. Also in most cases if concrete has never been sealed it will be extremely porous and require additional coats of sealer. Decorative concrete sealers usually cover anywhere from 100-400 square feet per gallon.
Best Reviews Concrete Sealer: Penetrating Waterproofing Concrete Sealers Edition
Best Bang for the Buck: Behr Concrete & Masonry Protector & Waterproofer
Bottom Line: A reasonably priced model with some nice features, some known issues, and a 10 year guarantee.
Pros: Excellent price point. Beads water nicely the first few months and is an extremely economical product.
Cons: Did not last the 10 years it was guaranteed to last for. Some owners stated it turn their concrete milky white.
Best of the Best: Siloxa-Tek 8500
Bottom Line: An exceptional concrete sealer from a company with a reputation for large scale commercial projects such as 432 Park Ave in NYC and the Orlando International Airport.
Pros: The Rolls Royce of concrete sealer. Need to see it to believe it water beading effect. Protects concrete and masonry from road salt damage, spalling, cracking, moisture intrusion, mold and mildew. Available in a concentrated gallon that makes 5 gallons leaving less of a carbon footprint.
Cons: Expensive.
*Available Amazon Prime Nationwide
Will do the job: Seal-Krete Original Waterproofing Sealer
Bottom Line: The best budget concrete sealer, the price makes it worth a second look.
Pros: Great for sealing in the fall and resealing in the spring and then repeating.
Cons: Shorter than average lifespan. Needs to be reapplied every few months.
Q: Is concrete sealer toxic?
A: Concrete sealers are available in three different forms: water based, solvent based and 100% actives/100% solids. The toxicity of a concrete sealer will depend on its chemical components. Generally speaking solvent based concrete sealers are going to be more toxic than water based concrete sealers. By viewing the SDS (Safety Data Sheet) you can view the hazardous statements and the precautionary statements associated with the product. Concrete sealers also contain volatile organic compounds (VOCs) which are emitted from liquid chemicals. Water based concrete sealers contain less VOC’s than solvent based sealers. VOC’s can be dangerous, have strong odors and result in adverse health effects.
That being said, solvent based concrete sealers tend to outperform and outlast water based concrete sealers. Water and solvents are used in concrete sealers to carry the active ingredients into the substrate and solvents are able to penetrate deeper and bond better. Solvent based concrete sealers can be more expensive than water based products. Now a days VOC regulations are set on a state level. Certain states are more strict with the amount of VOC’s allowed in a product for retail sale. For example certain areas of California have a VOC limit of 100 g/L. This makes it hard when shopping for a concrete sealer since manufacturers will not sell certain products to certain states. There are however, certain exempts solvents which are still allowed despite their VOC content.