Page 1 of 1
Posted: Thu Nov 10, 2005 7:32 pm
by Joan
....read the instructions
Your site does in fact answer 80 - 90 % of my posting though any additional comment would be most welcome.
But I do have (hopefully) one last qn. I recall that one posting is emphatic that surplus jointing sand should not be left on Concrete paviors during compaction - staining effect?!
However several other postings seem to suggest that this is not really a problem and it is best to leave a cushion / dusting of jointing sand during the whacker plate passes. Have I got the wrong end of the stick?
Perhaps you could clarify.
Thanks again :laugh: Joan
Posted: Thu Nov 10, 2005 8:15 pm
by Mick Leek
Think even i can answer this one.
So long as you are using SAND ONLY and not a dry mix of sand and cement then yes it is safe and correct to spread sand over the surface.
As you say it acts as a cushion and also is required so the dry sand filters down the joints. Remember to use joint sand Kiln dried or silca not building sand as this will not go down..
Think that is correct, but if not Tony will put me right...
Posted: Sat Nov 12, 2005 9:50 am
by Joan
Thanks Mick.
I now just look forward to the good weather forecast for the next few days.
Joan
:laugh:
Posted: Sun Nov 13, 2005 4:15 pm
by Tony McC
I always used to leave a light dusting of sand on the surface while compacting, but over the years I noticed that certain 'brands' of jointing sand had a nasty habit of being crushed into the surface of the blocks if a heavy vib plate was used, or if an area of blocks needed 'ironing' to persude high spot down to a suitable level, so I now teach that it's better to get rid of as much of the jointing sand from the surface as is feasible prior to initial compaction. With some jointing sand, and some blocks, it isn't a problem, but if you're looking for guaranteed perfection, best to brush it off.
Oddly enough, with some of the wet-jointing I've been observing lately (wet jointing relies on lots and lots of water to weash the sand into the joints and is used in winter months when the block surface is rarely dry), the crushing problem seems not to occur - or maybe it's just that I've not observed enough of it yet to experience a crushing problem.
Posted: Sun Nov 13, 2005 6:28 pm
by Joan
Thanks for 2 very full replies. Am looking forward to laying some blocks during the good weather of next week.
(Not too much frost we hope).
Thanks again
Joan
:laugh: