How to clean and retile outdoor sandstone pavers?

[claireme]

I have had these pavers down for several decades.  There are 2 main issues:

1. They have become quite grubby and no amount of high-pressure cleaning will remove the mould.  QUESTION: What would you recommend cleaning them?; and 

2. Some are missing and need to be replaced with new pavers. QUESTION: What would you recommend replacing broken, missing or hard to clean pavers? Liquid nails?

Thank you!

[MitchellMc]

Welcome to the Bunnings Workshop community @claireme. It's sensational to have you join us, and many thanks for your question about restoring pavers.

Given the pavers are so deteriorated, I'd suggest using 30 Seconds 2L Outdoor Cleaner and, once applied, give the area a good scrub down with a stiff bristle brush to try and agitate that grime and dislodge it. It might take a couple of applications as the grime looks rather well-adhered. Once you scrubbed the area, hit it with your high-pressure cleaner again to see if you have better results.

Liquid Nails Landscape is a good option if you're not planning on chipping away the mortar base that is in place. You can either chip away that mortar and then bed the new paver into the fresh mortar or leave it in place and use the liquid nails. Without chipping away the existing mortar, there will be no room for new mortar, causing the paver to sit proud of the surrounding surface.

Once you've cleaned and restored your pavers, it would be a good idea to seal them periodically with a paving sealer. This will prevent mould and debris from penetrating and staining the surface of the pavers. Here's a helpful step-by-step guide: How to seal outdoor pavers.

Please let me know if you have any questions.

Mitchell

[claireme]

Many thanks for the advice!

After sealing, does it need to be reapplied straight on the paver after it wears off or can I use the high pressure hose to clean again and then reapply sealer?

[EricL]

Hello @claireme

The sealer should conservatively protect the surface of your pavers for at least six months. If you clean the surface with a regular brush along with detergent and water, you should be able to prevent any mould buildup. I suggest only using your pressure cleaner if the surface really develops a large infestation of mould. Otherwise, I propose re-sealing the pavers only once a year depending on the condition of the paver.

If you need further assistance, please let us know.

Eric