Crystal substance near gas pipes

December 21, 2009 12:36 PM

Can anyone help us identify this substance and whether we should be concerned for our health.

Our kitchen fitter has recently hooked up our dual fuel cooker last Friday and we've only noticed this in the last few minutes. My fiancee and I are obviously concerned but can't ask until the fitter comes back tomorrow. In the meantime, is this something we should worry about?

The wall behind has been plastered 2 weeks ago and is an internal wall so no issues about the UK frost causing this. The substance has no smell and is crystalline in nature.

posted by SRMorris to home & garden (10 answers total)

I am not a plasterer, nor anything like one. To me, that looks like gypsum crystallizing out of the plaster, possibly caused by moisture or heat. But I want to stress that this is only a guess. If I'm right, it's not dangerous, but could be indicative of a problem.
posted by KathrynT at 12:39 PM on December 21, 2009

Looks like normal salt leech to me?
posted by TomMelee at 12:40 PM on December 21, 2009

...although I've never seen that on plaster/drywall.
posted by TomMelee at 12:41 PM on December 21, 2009

it's probably gypsum crystals from the gypsum in the plasterboard, flowering due to the heat/moisture behind the cooker. mostlly harmless, brush into pan and bin!
posted by snailer at 12:42 PM on December 21, 2009

Do you think it could be dust from bashing/sawing/chiseling through the wall while hooking up the fitting?

Oh, and if you are worried about a substance affecting your health, you probably shouldn't try sniffing it. But you knew that already. :-)
posted by springo at 12:43 PM on December 21, 2009

Thirding "gypsum crystals," also called "efflorescence."

If this were me, I'd apply an anti-damp primer and paint (after sanding away the efflorescence).
posted by Sidhedevil at 12:48 PM on December 21, 2009

Looks like efflorescence. White fluffy salt crystals that leech out of masonry due to moisture, which would have be present if you just had the wall plastered.
posted by cecic at 12:50 PM on December 21, 2009

I grew up in a house that had this outside and in, on every brick and every plastered wall. We called it leaching, and it looks awful, but it's not going to damage your health. If it's a long term problem (which it may not be if the plaster is new) it will eventually damage your wall by "blowing" the plaster so it loses integrity.
posted by Sova at 1:48 PM on December 21, 2009

Just wanting to thank everyone for their quick answers - my fiancee and I can sleep easier tonight without worrying gas is making us sleepy.

PS. Springo, your answer made us laugh - especially considering the first thing I did was sniff it!
posted by SRMorris at 2:32 PM on December 21, 2009

If you look close enough, you can see where there is a water stain behind the crystals. Water (or possibly even humidity) got into the plaster where the installers gouged it out. If it was me, I would ask them to slap a coat of paint onto it, or the wall will probably start to crumble.

(Or, it looks like they might have applied some plaster to the hole they made, and the water leached out of it.)
posted by gjc at 3:54 PM on December 21, 2009