Anybody know what this residue on underside of stairs is?

[Mmcgar]

Hi all, I posted a thread on here last week about problems I'm having with my stairs separating, and creaking etc. I was taking pictures in order to put it onto mybuilder but I noticed a whitish residue on the underside of the stairs and I have no idea what it is, I'm hoping it's not damp.

my stairs double back on themselves and are essentially 2 separate parts , this white residue is only on the bottom section. Does anybody have any idea what it could be and if it's anything I can fix?

Thanks in advance.

 

[gregers]

looks like something has been spilt from above and its soaked through,everything else looks as it should be to me.

 

[Robbie uk]

As its at the top, it could be dirty builders hands lifting the stairs into place when fitting it.

 

[drpepe]

the whiteish stuff just looks like the type of mould sometimes seen on the rear of furniture against a wall - when there's not much airflow and a damp-ish atmosphere.

Wouldn't have thought it is unexpected or much of a problem under the stairs.

 

[Mmcgar]

Thanks for replies. Mould was actually my guess at what it is this cupboard is at a sort of basement level so there is zero air flow. I'm not sure how big a problem it is i.e. can it cause any damage to the stairs.
I also noticed this stuff on the walls

 

[Mmcgar]

Those photos aren't great, basically there's white crystal like stuff on the walls. The other side of this wall is underground

 

[gregers]

look like salts to me.

 

[Mmcgar]

Hi gregers, what is salts? Is it a form of damp?
Thanks

 

[gregers]

mineral salts,google it and read up m8.

 

[ree]

The salts are mainly chlorides and nitrates.

The brickwork has previously been painted with plastic paint. Pressure from penetrating ground water is pushing the paint off and the salts are making it bubble.

FWIW: You could remove all paint back to brick and then go over the brickwork with a masonry paint.

Introducing some more cellar ventilation would help.

The light coating of mould on the stairs can be washed off with an anti-fungal chemical - its no big deal.

Just be future aware and check the area, and any nearby woodwork, say once a year.

 

[Mmcgar]

Thanks very much for the detailed info ree

 

[alanthomaswatson]

Have to agree with ree. The salts are technically called efflorescence and harmless. They occur generally but worse when the brickwork is underground as in a cellar. Having been over painted doesn't help. The staining is as suggested - just some mildew or similar growth from moisture. It's not a problem but suggests a general lack of ventilation. This should be introduced if possible - an old air brick has probably been removed.