Rust spots on new upvc window sills - is this possible???

9 Sep 2004
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United Kingdom
:?: I wonder if someone could advise me please?
Having had new upvc windows installed only 3 months ago, I was really pleased with them until today when I opened one of the upstairs windows and noticed that on the outside sills were what looked like rust spots on.

Can modern upvc that is supposed to conform to such high standards 'rust' in this way? This really does look like rust.
I tried to clean it off, but the spots are still visible, although lighter in colour, and actually look as though they have permeated the plastic. They are very unsightly and I'm just hoping the problem won't worsen.
As yet, this has not happened on the windows themselves.

I had been very impressed with the company that installed them. I believe they are a reputable company, are members of the Glass & Glazing Federation and have full indemnity. I have guarantees from FENSA.
There was no hard sell, 'phoning head office' nor any pressure to buy. - the windows sold themselves to us and they have been excellent, apart from this problem.

I have not yet approached the company, who were efficient, reliable and professional as far as the installation was concerned and who I'm sure would be keen to put matters right, but I wanted to ask someone's opinion on this forum as to whether this could indeed be rust or something I could take care of myself, before calling them out perhaps unecessarily.
Thank you.
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If these are small brown spots about 1-2 mm in diameter then they are probably spider s**t. I kid you not! They can be a devil of a job to remove but you should get some joy with some Flash and a nylon (non abrasive) scourer.
another possibility is a metal object left to rust then removed[knocked off]
it only takes a few day for rust to discolour plastic
but it can only happen from an external contact by metal

big all
That's what I was thinking, if they drilled through any metal reinforcing the frame the swarf could lay on the window cill and rust.

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I wonder if you could use bleach on upvc?
Bleach won't help (if it is rust that is) in this instance, bleach is a powerful oxidising agent, not what you want.
Thanks very much all of you - I loved the spider one; you never think of them needing - ahem - to use the bathroom :!: but it does make sense and I suppose they must 'go' sometime...........
With the benefit of all this helpful advice, I actually think it's a mixture of the spiders (I found a web nearby too) and drilling through the metal reinforcing the frame.
The tiny spots (ie the spiders' offerings) cleaned off eventually with a lot of elbow grease, but the larger one which measures about 1cm diameter, has not really shifted - I think this one is in fact where rust is coming through, as mentioned in the other posts.

My main worry was that the plastic itself was corroding, which now doesn't appear to be the case.

It took us a long time to find the right DG company because we wanted a 'sliding sash' upvc window to match our Edwardian house and we found them here, so in case anyone would like to know who they are, it was Crystal Windows of Romford, Essex.

We have no connection with them, but can thoroughly recommend them as they ticked all the right boxes with absolutely no sales 'speil.'

Advice was really appreciated - thanks again
I have not yet approached the company

There's no harm in asking them if they know how to remove marks like this - you never know they might even come round and do it for you!
heeelllooo y p

I think this one is in fact where rust is coming through, as mentioned in the other post

the oxidiation can only happen from an external source [pvc dosn,t
contain any metal] in other words discolouration can not come from
within the plastic

big all
I've found (regrettably) that if you clean something (such as copper pipes), the tiny fragments of steel wool, which break off during rubbing, always seem to land somewhere really important. As soon as these almost invisible particles combine with the merest hint of dampness, they produce near-impossible to shift rust spots, regardless of the surface!
for anyone wanting to know about this.its more than likely your pebble dash.normally the golden stones contain iron content and thats enough.i have the same problem and wondered if anyone know of any miracle cleaners to remove the stains?
A bit of T cut and some elbow grease.

When you wash your windows on the outside use car wash and wax, It will leave a protective wax layer and also make cleaning them easier in future.
Speaking from experience :D i would say this is likely to be 2 things, either metal shards from someone grinding or cutting metal at some point during installation peppering the cill with hot sparks which embed themselves intot the pvc invisibly it seems until they start to rust, another possible cause and it was proven here in Derby when it went to court that a local steel fabricator was spewing out shot blasting beads into the atmosphere due to poorly maintained equipment and this was settling on peoples nice shiny white windows................till in turned to rust :confused:
Has anyone been having a crafty smoke out of your upstairs window? Cigarette ash can cause brown burn marks.
its 100% the sunflower/barley corn golden dashes as theres many posts onhere about the stones contain ferous material from when they are mined.hence why you sometimes get what looks like rust marks on new dased houses.there is a book you can get and it tells you which dashes contain these.i was recommended it off this forum years ago.grinding close by would also have the same affect as you can see the rust marks on the ground after its rained.

it does sound stupid and i didnt believe it myself but google or search the forum and it is true.

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