Where is this damp coming from? (with pics) 17 January at 4:13PM in In my home (includes DIY) MoneySaving 45 replies 1.8K views

silvercar

Doozergirl said:

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.  

 

That means calling someone in. Which isn’t going to happen in the short term.

short term solutions please. Can I fill in the holes with this stuff https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

and is there a sealant/ paint I can put over the bricks to stop splashing rain being absorbed into the brick work?

MikeJXE

Doozergirl said:

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.  

 

That bead is only required when the render is flush with the brickwork

In the case of this job there is one course of brick set forward to whats below and that course is the drip 

Sort out any unfilled brick joints and stop the rain splashing up the wall 

stuart45

Where the render meets the oversailing course, there is a slight gap where water might be tracking through. It's worth trying the full that and the joints to see if it helps.
Was the inside chimney breast there when you moved in?

Doozergirl

MikeJXE said:

Doozergirl said:

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.  

 

That bead is only required when the render is flush with the brickwork

In the case of this job there is one course of brick set forward to whats below and that course is the drip 

Sort out any unfilled brick joints and stop the rain splashing up the wall 

I initially thought there was but I don't think there is.  I think the wire and the tape creates the illusion of one. 

I think it is flush.  

diystarter7

Doozergirl said:

MikeJXE said:

Doozergirl said:

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.  

 

That bead is only required when the render is flush with the brickwork

In the case of this job there is one course of brick set forward to whats below and that course is the drip 

Sort out any unfilled brick joints and stop the rain splashing up the wall 

I initially thought there was but I don't think there is.  I think the wire and the tape creates the illusion of one. 

I think it is flush.  

I concur.
Thanks

Doozergirl

silvercar said:

Doozergirl said:

silvercar said:

Would this work?

https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

You need more than that.  You need to hack back the render slightly and install the render bead referred to by Section62, and then re-render.  

https://www.rendit.co.uk/renderplas-white-bellcast-bead-25m-renderplas-10mm-bellcast-bead-25m-white-2

Can you see how it brings the render away from the mortar joins of the brick and also tilts slightly down so water drips clear of the wall, it doesn't run into the mortar at all.  

 

That means calling someone in. Which isn’t going to happen in the short term.

short term solutions please. Can I fill in the holes with this stuff https://www.screwfix.com/p/no-nonsense-mortar-repair-grey-310ml/361jp

and is there a sealant/ paint I can put over the bricks to stop splashing rain being absorbed into the brick work?

By all means use that to attempt to plug the gaps, but water will find its way into the tiniest of spaces and if that render is sitting flush to the wall, you have an ongoing problem that isn't really going to be solved by a bit of filler.  Like the render issue on another current thread, you could rake out and put some silicone across the length of the join there but it isn't a permanent fix and the effort isn't hugely less than the permanent fix. 

There is a fundamental design fault there. 

silvercar

I think the picture isn’t clear from face on. Here’s a rough profile. In other areas of the house the render finishes slightly further out than the brickwork, in some places it meets properly at the join and what I thought was poor paintwork edges onto the brick, but probably helped seal.

silvercar

I can also see in other areas there is what can best be described as a cement skirting board. I wonder if that would be the line of the dpc that is missing in this area? 

silvercar

stuart45 said:

Where the render meets the oversailing course, there is a slight gap where water might be tracking through. It's worth trying the full that and the joints to see if it helps.
Was the inside chimney breast there when you moved in?

Chimney breast was always there. We have capped it years ago. There is no water coming down the chimney and no water marks internally where the chimney breast is.

stuart45

silvercar said:

I can also see in other areas there is what can best be described as a cement skirting board. I wonder if that would be the line of the dpc that is missing in this area? 

Could be a sand/cement plinth. These often cause damp problems at the base of walls, the very thing that they put on the wall to stop.