Wet patches on K-render after heavy rain

[rayman500]

Hi everyone, wondering if anyone can help diagnose what is happening with our external render? We have just moved into the house and the render was done around 6-12 months ago, I believe it is K rend. After recent heavy rain I’ve noticed a number of wet patches on the render, around the window sills and a larger patch down the edge of a bag window. This doesn’t (yet) seem to cause any damp problems internally. The patches disappear after a few hours but the bigger patch sometimes takes a day to go completely. I had a look in the rain and couldn’t see anything obvious like gutter leak etc. Seems like the water may be running along the sill and potentially either ponding or seeping into the render at the joint with the sill, but im not sure! Any ideas would be much appreciated. Photos attached!

 

[raytheplasterer]

that would be because you haven't got any mastic.

 

[smoother09]

Pretty obvious really!

 

[rayman500]

that would be because you haven't got any mastic.

Thanks for responding! Do you mean seal around the interface between the render and the Sill? Any recommendations on a product to use (if there's anything better than standard silicone to use?). The windows were in before the render so I assume they are sealed beneath the render, is the staining caused by water being trapped behind the render?

 

[smoother09]

That crack gonna get worse lot going on in this corner get it sorted sooner rather than later whenever it rains it's just gonna keep getting behind there! If you don't get it sealed in soon might start having problems indoors!

 

[rayman500]

That crack gonna get worse lot going on in this corner get it sorted sooner rather than later whenever it rains it's just gonna keep getting behind there! If you don't get it sealed in soon might start having problems indoors! View attachment 61102

Would you just seal up the crack with a exterior silicone type product? Would it be repairable in a more long-term way by a renderer e.g. can you touch it up with something permanent?

 

[Brimstone]

These days silicon is the permanent fix. Do it quick, any quality exterior silicon will do.

 

[smoother09]

Get silicone man in!

 

[owls]

As said, silicone sealant.
Your frames will contract in the sun your render won’t. You require siliconing around the perimeter, with a silicone of 20% flexibility.

 

[raggles]

Would you just seal up the crack with a exterior silicone type product? Would it be repairable in a more long-term way by a renderer e.g. can you touch it up with something permanent?

Ask for or buy frame sealant not just any old silicone.

 

[essexandy]

Of course you could always give the building company a buzz and get them to sort it out. After all it been missed by mistake.

 

[rayman500]

Sorry for the stupid questions… I sealed around the sill with some SIKA sealant and there still seems to be water ingress around the crack area. Should I seal along the vertical crack in the render where the bay meets the wall? Also should I be sealing right around the window frame rather than just the sills? Thanks!