How to prep and seal new pour driveway?

[okaku]

Hi everyone, I had my aggregate driveway poured about 2 weeks ago. and now I am seeing patchy white marks or spots that won't go away even with scrubbing.

I forgot to include the seal on the quote and now I am hopping to learn how to do it my self.

From my research the white marks might be efflorescence, but I am not sure which product to use to clean and seal afterwards.

So I am hopping to get some guidance on the products and proper step to follow?

Thank you! 

[MitchellMc]

Welcome to the Bunnings Workshop community @okaku. It's wonderful to have you join us, and many thanks for your question about driveway sealing.

I'm sorry, but could you please clarify what type of driveway you have? I am guessing it might be an exposed-aggregate concrete driveway or perhaps a Pebblecrete driveway. If we can confirm what it actually is, we can point you toward the right cleaning products and the correct type of sealer. If you can share a couple of photos of the white marks you are seeing, that will help confirm whether it is efflorescence or something else. Let me know if you need a hand uploading images. 

It is also worth contacting the contractor who installed the driveway, because they might be able to advise on the appropriate sealing process for that specific finish. Once we know the material, we can guide you through the right steps to clean and seal it properly.

Please let me know if you have any questions.

Mitchell
 

[Nailbag]

Hi @okaku 

I suspect most likely from either a poor mix from the supplier or it hasn’t been acid washed evenly. The later was the issue causing my similar issue some years back. 

I would contact the concreter to assess being just poured. 

Nailbag

[okaku]

Hello, Thank you for your reply.

It is an exposed aggerate concrete driveway.

Unfortunately the contractor is fully booked at the moment, and I was just wondering if I could do the acid wash and sealing by myself.

Thank you 

 

[JacobZ]

Hi @okaku,

I'd suggest using the Dulux Avista Exposed Aggregate Concrete Sealer for your driveway. It is a solvent-based coating designed specifically for exposed aggregate and does a good job of enhancing the colour while protecting the surface from stains, dirt and weather.

While acid washing and applying the sealer, please remember to wear appropriate protective equipment, including long protective clothing, enclosed shoes, a mask and gloves.

Following along with the instructions, they recommend that if the concrete is more than 5 days old, which I assume it is, to acid wash it with Hydrochloric Acid, mixed to a ratio of 20 parts water to 1 part acid. You should then wet down the driveway surface and apply the acid mix to the driveway with a watering can. The acid mix will begin to fizz, which indicates it is working. You should allow it to sit for 5-10 minutes before flushing with clean water, then pressure clean the driveway.

After acid washing, allow the driveway to fully dry, using the dry test described in the instructions to ensure it is fully dry. This involves taping a 450x450mm piece of plastic, then leaving it for an hour before checking to see if there is any moisture beneath it. Once dry, you can move on to sealing.

To apply the sealer, give it a mix, then pour it into a paint tray and apply it with a roller on a pole such as this UNi-PRO 230mm Roller On A Pole With 1.55m Extendable Handi-Pole. They recommend you use a 20mm nap lambswool roller cover, such as this UNi-PRO 230mm 20mm Nap Genius Sheepskin Roller Cover. Apply your first coat evenly, then allow it to dry for two hours before applying a second coat.

After application, it is recommended that it is protected from water for two hours, pedestrian traffic for 24 hours and vehicle traffic for 3 days, so make sure to factor these times in when planning the work.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[okaku]

Hi JacobZ,

Thank you for the comprehensive guide. I will surely give it a try.

I have also noticed some of the stones are starting to flake off from the concrete. Is this a normal thing since it is not sealed? 

[JacobZ]

Hi @okaku,

The process to create an exposed aggregate driveway removes the top layer of sand and cement that sits between the stones and bonds them together, so it is not uncommon for some of the stones to come loose.

The cleaning process will remove the majority of the loose stones, and once the driveway is sealed, things should be better held in place.

Let me know if you have further questions.

Jacob

[okaku]

Hi @JacobZ ,

When I was cleaning the driveway, I noticed some of the concrete has come out.

Do I need to fill these holes with filler before doing the acid wash?

Also I am thinking of sealing my garage concrete slab as well, do you have any product recommendation?

I prefer something that can be done DIY. Epoxy looks good, but I sounds like it need special skills to get it right. 

Thank you

[MitchellMc]

Hi @okaku,

I would be extremely hesitant to seal a surface that has been poured for you unless you've spoken to the installer, they have advised the product to use and specified how to prepare the area. Say, for instance, these stones continue to fall out even after it's been sealed. You would have a very difficult time trying to claim a warranty on the driveway. I would suggest you contact the installer and ask them these questions. Firstly, when can they do the sealing and is it suitable to wait that long? If it needs to be sealed now, what product should you use? Our sealers for exposed aggregate may not be the same type that is recommended or used by the installer. You certainly don't want to use a product that the installer does not recommend.

My main concern here is that most of your stones are very proud of the surface, whereas you'd typically see at least 50% of the stones within the concrete layer, which locks them in position. The fact that you already have stones falling out could mean that the proprietary sealant was required to hold them in place.

As for your concrete, you can use Crommelin 10L Gloss DiamondCoat Paving And Concrete Sealer, which is a one-part sealer and easier to use than an epoxy.

Please let me know if you have any questions.

Mitchell