Sudden mystery yellow stain on wall

[Tiddlywink]

Hello everyone,
I’ve never posted in a forum before, I’m hoping someone can help. Please see pic. It’s suddenly appeared. I have had the roof valley replaced recently and this has not made a difference. There were orange dots appearing too, tho I wiped these off as I thought could be some sort of mushroom developing. The yellow wipes off onto tissue though it seeps back through again in a about 15-30 mins as it was before.
I have asked my builder, who can’t see any water ingress evident from the outside wall. The stain itself is on the upper wall in between the kitchen and French doors of a typical Victorian mid terrace. I’m not sure what info to give so please ask away. I really appreciate any help and guidance you can offer. Thank you

 

[JohnD]

It is a water stain.

I see the picture rail has been altered. Was there previously a chimneybreast here?

Please stand back and take a wider pic of the entire wall, right up to the ceiling.

In the loft, please take a pic of what's above the wet wall

And external pics, of the entire wall and roof above. Include gutters, downpipes, chimneys and plumbing.

 

[Tiddlywink]

Hello John,

Thank you so much for your response.

The loft has been checked for wet and as a result the roof valley has been replaced. 2 roofers and a builder have said the roof is now good. The builder has checked the outside wall for any water ingress and nothing can be seen. The guttering has been replaced. the chimney has been repointed and all damages sorted. This stain is new and since the forementioned work has been done.
I have wiped the stain away and its almost like oil ? it comes off yellow onto the cloth and then within minutes its seeped back through again.

 

[JohnD]

Is the stain on the ground or first floor? What is above the stain, inside and out? Is there a bathroom, radiator pipe or other plumbing nearby?

In picture 3 there is a gutter ending in a corner where two walls meet. Where is this stain, relative to the walls?

 

[Tiddlywink]

Hi John,

It’s ground floor, bathroom is above the kitchen.
Photos attached are the other side of the stain (the corner of the kitchen) and the outside wall linked to the stained area.

 

[Tiddlywink]

Here’s a couple more pics.. bedroom - area between window and bathroom door is above the stain. Pic showing bathroom and plumbing near by and above stain.

 

[foxhole]

Looks like rain could be hitting the timber ( why is it there?) and soaking thru taking some colour from the timber.
Roof level gutter seem to cross and their placement could allow rain down the corner as it misses the gutters. Has the overflow pipe been running , looks too short to clear the timber.?

 

[Alec_t]

There's a water mark down the brickwork in your post #5 first pic. Is that significant?
Is the black timber in that pic a new addition? Water from the overflow pipe or gutter above it could get trapped behind the timber.

 

[RandomGrinch]

I think it would be worth attempting to lift a floorboard in the bedroom above the stain, and seeing if anything is happening within the floor void - plumbing problems could then be ruled out, and the external timber becomes the likely culprit.

 

[Tiddlywink]

Hey Foxhole and Alec

Thanks for taking the time to look at the pics and my post. The black wood work is part of a pagoda (think that’s what it’s called) currently taken down due to decking work about to start. I have only stained the timber black today.

The water stain on wall is the result of issues with the valley. The valley has now been re laid. There was water pouring through the gap onto the wall, this no longer happens.

There is a gap between the timber and wall see pic. Is the wood being there causing the issue?

 

[Tiddlywink]

Hi RandomGrinch,
Yes, that makes sense, ill see if I can take some floor boards up and have a look

 

[foxhole]

If the repairs are recent damage could take months to dry, If you have wall paper at that location best removed.

 

[Tiddlywink]

No wallpaper, just lime plaster (mostly blown!) and paint so that’s good.

 

[JohnD]

Tie a plastic bag over that overflow pipe.

You mark is a water stain

If water is coming out of that pipe it may very well be the source.

What is the pipe attached to?

 

[Tiddlywink]

Good morning John,
The pipe is obsolete.