New Build - Marked Rendering

[Rafka]

We bought this new build 4 years ago. I noticed this stain this morning so it probably just appeared. Does anyone have any idea what it could be?

[E-bmw]

It certainly looks like water to me.

[Magooagain]

Looks like someone has chucked a burger at it. Oil stain like.

[OutInTheShed]

From the picture, you can't rule out something splashed onto the face of the wall.
Sometimes a bit of plant or animal 'stuff' gets on the surface and slows the drying of dew etc.

Around here, all rendering grows lichen and god knows what within a few years.

[Rafka]

JpManning said:

Can't see the photo properly at my end, but on render a few years old a sudden dark patch usually comes down to water getting in somewhere. First things to check are directly above it: window sills without a proper drip, cracked or missing sealant round the frames, a leaking gutter joint or overflow, or a pipe dripping onto the wall. If it's white and powdery rather than dark, that's likely efflorescence (salts coming out as the wall dries) and it often brushes off and stops on its own. If it keeps spreading or there's damp inside, get the warranty provider involved, as a new build that age should still be covered for that sort of thing and it's better logged early.

Thank you. Unfortunately I noticed it just before we left for a holiday. I’ll see how it looks when we’re back.

[Red9zero]

JpManning said:

Can't see the photo properly at my end, but on render a few years old a sudden dark patch usually comes down to water getting in somewhere. First things to check are directly above it: window sills without a proper drip, cracked or missing sealant round the frames, a leaking gutter joint or overflow, or a pipe dripping onto the wall. If it's white and powdery rather than dark, that's likely efflorescence (salts coming out as the wall dries) and it often brushes off and stops on its own. If it keeps spreading or there's damp inside, get the warranty provider involved, as a new build that age should still be covered for that sort of thing and it's better logged early.

The warranty will be with NHBC, who will do all they can to get out of it. The house we have just bought is four years old and had a very bad damp problem in the garage. After any kind of rain there would be a large puddle emanating from the rear wall. Despite it apparently being a known problem on the development (of 50 houses), only one has had a successful resolution. We gave up after being told basically to live with it, and got the rear of the garage tanked. Predictably enough, NHBC and the builder now want to inspect the damp