Cleaning Red cobble lock patio

maynooth_rules

Hi, we moved into this house last year but can't get the red cobble lock to come up clean, constant black marks on most stones. Power washer does little to help, anything anyone can advise?

glog

Get some Chlorus (Sodium Hypochlorite) from your local Farm supplies.
It is normally 15% - handle and use safely, with adequate PPE.
I would dilute 5 parts water to 1 part chlorus.
Wet patio with hose, apply the solution, wait up to an hour and wash off.

With any power washing on brick paving you may need to re-sand the joints, depending on how hard you were with the washer.

Roosterreid

glog wrote: »

Get some Chlorus (Sodium Hypochlorite) from your local Farm supplies.
It is normally 15% - handle and use safely, with adequate PPE.
I would dilute 5 parts water to 1 part chlorus.
Wet patio with hose, apply the solution, wait up to an hour and wash off.

With any power washing on brick paving you may need to re-sand the joints, depending on how hard you were with the washer.

I second this...... its very effective.

I would dilute less than 5 to 1 (maybe 3 to 1) but you need to be careful of run off as it can kill grass.

Black_Knight

Yup. Same. Not red brick on ours, but paving nonetheless.

I second the more concentrated mix. 3:1 seems about right. I use a weed sprayer to apply it liberally to the paving. I don't wet the paving prior either, I find that dilutes it too much. Do it out of direct sunlight too, gives the mix a chance to attack the paving.

Your red brick does look very... not red though. I find the Sodium Hypochlorite great for cleaning off algae/moss. Worth a try though.

Important note. Have some silica sand ready to go when the driveway is clean and dry. Powerhosing will lift out loads of the sand between the pavers, and you'll end up with blocks falling/shifting in no time. Pricey business to undo it all vs. a few quid for silica sand and a yard brush. Do this once a year. 1 bag will last you ages if kept clean and dry.

Congrats on the new house.