avoiding efflorescence

DIYedboy · 7 Apr 2009

I want to do some feature brickwork outside, but I don't want it ruined by efflorescence 6 months later. Is there any way I can guarantee not to get it?

jeds · 8 Apr 2009

Choose a brick that is rated low efflourescence and Keep the bricks as dry as possible.

DIYedboy · 8 Apr 2009

Thanks Jeds, is it exclusively the salts coming from the brick? or is there some also in the mortar?

Symptoms · 8 Apr 2009

boy - also consider using washed sand.

stuart45 · 8 Apr 2009

Washed sand is less likely to contain salts, but it is a bit more difficult to work with.

jeds · 8 Apr 2009

Principally the bricks but the mortar can also contribute. Using washed bricklaying sand is good advice. Also use clean water.

It's worth noting that it is impossible to say that efflourescence can be avoided completely in all situations. But the above precautions will lower the risk dramatically.

^woody^ · 8 Apr 2009

Having a suitable coping with suitable drips will reduce the likelihood of the wall below efflorescing

DIYedboy · 8 Apr 2009

Thanks for all the advice lads..........washed sand? is that what they call plasterer's sand?

noseall · 9 Apr 2009

Feature brickwork + rinsed sand = nightmare.

stuart45 · 9 Apr 2009

Even sand that's been out in the rain too long can be more difficult to work with. You have to lay bricks with different sands to know just how much difference it can make.

noseall · 9 Apr 2009

stuart45 said:
Even sand that's been out in the rain too long can be more difficult to work with. You have to lay bricks with different sands to know just how much difference it can make.

Words of wisdom. Only experienced trowels will know what you are on about.

People who have never laid dry bricks, wet bricks, hard bricks, porous bricks, had to muck up, screw down, corbel out, over-sail, lay in the rain - these are the people who blather on about using rinsed sand.

DIYedboy · 9 Apr 2009

I've laid a few hundred bricks in me time including oversailing courses and dentil brickwork and I know the nightmare of laying porous bricks in the sun, but obviously I haven't the experience you boys have. Anyway, are you saying I should be using plasterer's washed sand instead of soft sand to help avoid mortar efflorescence?

stuart45 · 9 Apr 2009

For bricklaying I would use building sand. Even some building sands are similar to washed sand. I have always found the yellow sand to be the best. Washed sand mortar is more difficult to spread, the bricks won't push down properly and its harder to butter the cross joints. You used to get this on sites when they delivered both types in the same truck and tipped the load off together. Builders merchants never seemed to understand the problems that the wrong sand caused.
Even if you do get some efflorescence it's not a serious problem as it will wash away in time. It normally comes from the bricks anyway.
Lime run off is similar (often mistaken for efflorescence) and will occur whichever sand you use.

chappers · 10 Apr 2009

I wouldn't worry about the mortar just make sure you buy dry bricks and keep them dry, that includes any exposed courses during the build.

DIYedboy · 10 Apr 2009

fair enough, soft sand it is (i've only used plasterer's for rendering). I intend to build a pair of hexagonal columns that twist as they ascend, so with all that effort you can appreciate that efflorescence all over the show ain't the way to go!

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avoiding efflorescence

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