My son-in-law has bought a "build it yourself" "stone" firesurround, The instructions are not very clear. For setting the hearth on a bed of mortar it is a bit ambiguous as to whether wetting the stone is a good or a bad thing - it refers to one or the other drawing the moisture out of the mortar without it being clear as toy wheter this is a good or bad thing.
What would you suggest?
mortar needs to stay wet to set properly, so wet anything porous like bricks that it is to attach to
AIUI, it always a good idea to wet any surface that you're going to mortar, not excessively, but just so that the mortar 'takes' to it.
If you wet the stone it won't absorb much water. The idea is that no dust will serve to work as a release agent as in mold release wax. With wet surfaces the lime carries around any dust particles and the bond is stronger.
Who mentioned lime?
That isn't how bricklaying and blocklaying is done.
+1. Cement needs to stay damp for a number of days to gain strength. OTOH if it's stone, lime would be a bit better.
NT
Did the OP mention any other kind?
Isn't principle constituent OPC lime?
actually, it is if the bricks are really sucky.
But with average bricks you simply use a wetter mortar nix on the basis that some of the water will suck into the brick anyway.
No.
The principle constitituent is Portland cement
Drivel.
It doesn't want to be bone dry. But wetting it too much will cause unsightly cementy stains to appear on the face of the stonework as excess water runs down the face & spoil the appearance.
So, all a matter of degree.
Cementy marks can be removed with brickwork cleaner. (After cement has set). Be cautious as it's acid and can affect some stone (limestone).
They never are and block are a lot more sucky.
The consistency of the mortar is entirely determined by how it needs to be when doing the laying and that is determined by how it sags in use.
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Exactly. if the bricks suck, you make it wetter so that once the bricks HAVE sucked, you get the right consistency.
Have you actually ever laid a course of bricks?
It is when I do it! Though it depends a bit on wind, temperature and humidity.
If it *never* happens why would brick manufacturers or suppliers give instructions on how and when to do it?
"Only with high suction rate bricks in warm weather conditions should dunking (or wetting) of the bricks be considered. If it is undertaken the bricks should not be soaked and only clean fresh water should be used to avoid soluble salt contamination"
You don't in fact do anything of the sort because no bricks suck very much.
Lot more than one course thanks.
I doubt it, because I have laid with bricks that suck a HUGE amount
Have a guess who you are replying to ...
snip
Me too, especially with reclaimed bricks that might well have been locally made a long time ago.
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