Block paving cleaning

[orson]

I'm doing a block paving cleaning job next week, never done it before. I spoke to Marshalls and they don't recommend pressure washing!!!. Has anybody ever had any problems when doing this type of work? I also enquired what amount of sand will be required to top up the blocks, the young lady at Marshalls quoted 6-8 sq mts per bag, this seems very low. I don't want to be left with bags of sand over at the finish as they always seem to rip before I can use them on another job. Just hope the weather stays dry so I can do this job in one visit.

[Rich H]

You'd be better off subcontracting to someone with the proper kit and experience like Roger from R&A Pressure Washing.

A little Kaarcher or some such isn't up to the job. As for the sand, it'll depend on how much gets blasted out. 15 sq.m/bag ought to do it.

But there's no chance of doing it in one day. It needs time to dry out thoroughly before you brush in the sand.

[Edgecraft]

Hi Orson

I always use a rotary surface cleaner to clean block paving as the angled jets don't tend to remove that much sand from the joints and also it cleans more uniformly avoiding striping, you still have to use a lance in certain parts but use should be kept to a minimum.
I find that one bag of kiln dried sand usually does around 50 sq/m and I usually go back the day after (weather permitting) to make sure the the paving has dryed out properly unless the sun is cracking the flags then I might re-sand in the evening.
I always weed as much as possible before starting as it is amazing how much crap you have to clear up afterwards, and trust me it isn't pleasant when it is in slurry form !

Darren

[orson]

Hi Darren,
Thanks for the info, I've got a rotary jetter ordered for hire on monday already. The entire area has already (two weeks ago) been given a good spraying with Roundup and Mossicide (never mix these two if you want to be able to use your sprayer again)> Once clean I'm giving the entire area a good dousing with sodium chlorate before sanding.

Cheers

Orson

[Tony McC]

Regarding the coverage for sand, that figure of 6-8 square metres per bag is about right for new work. For topping-up after power-washing, it could be anything from 10-50 square metres, depending on how much is removed be the washer. The less the better.

[orson]

Well, did the job in three visits (I was far too optimistic on that point). I was amazed at the amount of crap that the rotary jetter lifted, seven 20kg buckets in total. managed to push most of the slurry into the acco drain (I stuffed the business end of it with a load of rags) so most of the water drained away before scooping out the crap with a garden trowel. 110 sq mts took all day and well into the evening. Two 25kg bags of sand did the topping up a couple of days later.