Damp in kitchen

[Dan45]

I recently had my kitchen renovated, in a Victorian terrace house I've just bought. A couple of weeks after painting, damp has started to show above the skirting on both the external wall (underneath the bay window) and internal wall next to it.

Under the bay window:

The internal wall:

Any idea what sort of damp this is?

 

[Burnerman]

Rising or penetrating, which isn't much help to you!
Can you give us some idea of the exterior condition regarding air bricks, and the condition and sealing of the window frame? Is there any evidence of similar concern further along on that wall at all?
John

 

[Dan45]

Thanks for your reply John. I'll have a look when I go there today, and take a look

 

[Burnerman]

Cheers Dan - is there any chance of lifting a floorboard or two in the vicinity, or are those tiles stuck down? (can't see, small screen )
John

 

[Dan45]

They're stuck down unfortunately...

 

[Dan45]

Sorry for the delay Burnerman. The damp is only in the bay - I've got some photos of the outside wall. There's some vents which are actually above floor level, which were there when I moved in a couple of months ago. Before I had the tiles laid, I got 2 deeper vents made (in the middle and left of bay), which are actually below floor level. You can see the hole for them in the photos.

Right of the bay:

And higher up:

Right side of the bay:

Middle of the bay:

Left side:

 

[Burnerman]

Thanks for the pics, Dan.
What immediately springs to my mind is that the ground level outside the bay is much too high.....there's every chance of moisture wicking its way up there, although the two small air bricks may help keeping the cavity dry (assuming it isn't full of rubble, of course!)
Is there any chance of digging a trench through the concrete, alongside the wall to a depth below the damp course?
You can also expect water wash from the bay window and rain splash helping to keep that external wall damp.
Is that render hiding poor condition brickwork, do you know? It would seem that whoever put it on was trying to cure exactly the same problem!
John

 

[vinn]

1 - the yard concrete is too high.
2 - the render is bridging the DPC. The render should be completely removed or at least cut away for 50mm to break ground contact.
3 - can you mark the photos to show exactly where the FFL is on the bay?
4 - the house walls appears to be solid.
5 - there is no purpose for the air vents higher than the kitchen doorstep.
6 - the new vents: what is the purpose of the "hole" unless you are going to use vents at a lower level?
I assume that the bay floor is suspended?
7 - the sill throating is allowing drip back on the RH side dark green area.
8 - the window frames need re-sealing.
9 - have you been below the bay area floor & examined the joists for rot?

FWIW:
- the gulley appears to be blocked - clean out the gulley, grating and trap.
- the bay roof flashing is wrong & needs re-doing in stepped cover flashing - with the sand & cement filett removed & cleaned off.
A "Kickout" is needed at the bottom of the flashing to direct water into the gutter.
- Various applications have been applied to the brickwork - presumably to deter damp. The brickwork needs cleaning up.
- In a traditional build all external pipework should be in black plastic.
If the soil pipe after the WC elbow is a vent to roof then there are better ways of arranging it.

What did the mortgage surveyor have to report about these things?

 

[HERTS P&D]

I'm going for number 7.

Andy

 

[Dan45]

Thanks for all this info, Burnerman and Vinn. Sorry for the late reply - I've just got back from holiday.

The red line in this image shows the level of the floor (from the top of floor tiles) inside the kitchen. The tiles are 20mm thick, and there's ply underneath that, so it could be that the yard concrete is actually slightly higher than inside the kitchen.

Vinn, the holes have vents inside them. I had this done recently because some of the joists under the floor were rotting. There was no ventilation there a tall, and this was the only way I could get some air down there. I replaced the rotting joists.

I had a close look at the window seal, and yes they definitely need resealing.

What do I need to do about the sill throating to stop water dripping back into the wall?

So, is the consensus that I remove the rendering, or at least make a break in it, and lower the level of the yard concrete, perhaps to the level of these new holes?

 

[Burnerman]

In a few words, yes.....the concrete level needs to be lowered to below DPC - its really the only way you are going to get somewhere.
If the window sill has no drip groove, one way is to run a bead of silicone just under the edge.....water runs down the sill, onto the silicone bead and drops clear. Not the best but it does work!
John

 

[HERTS P&D]

see below:

 

[Dan45]

Thanks Burnerman, so how can I find out where the damp proof course is?

And thanks for the video HertsDrainage, very helpful!

 

[Burnerman]

The DPC should be visible down the holes where the larger air bricks are and you need to excavate to two brick courses below that if you possibly can. Its all covered by render, of course - and ideally that should stop at the DPC level with a bell cast to allow water to drip clear.
John

 

[Dan45]

Thats great, thanks