preventing damp issues

[JordansDIY]

Please see attached images that show Damp Proof Course overlapped by pebbledash and also a different wall which has a DPC that is very close to the ground (less than 15cm).

I’ve read that this could cause bridging issues as the pebbledash goes over the DPC level?

Would you recommend me removing the render up to above 15cm and putting in Damp proofing dryzone rods to make sure they are below where the pebbledash ends.

Any help would be massively appreciated!!

[JordansDIY]

Please see images attached - error on first post

[dewaltdisney]

Those drill holes indicating the line of an injected chemical damp course do seem to go above the dash. I would be guided on whether you are getting damp internally before you start looking at chipping away the finish to a new line above and replacing the finish drip sill. While you are at it, your condensate pipe could do with new insulation to avoid a freeze and boiler lock out in winter.

DWD

[JordansDIY]

Many months ago I used a protimeter and it had high levels of moisture readings on some of the internal walls.

There is probably a number of potential reasons as there was a leaking pipe in the upstairs bathroom and leaky kitchen tap.

I’ve already hacked off halfway up the kitchen and removed the plaster so it’s bare brick now.

Im sorting the external part out too to prevent any other issues occuring in the future even though its not clear if it was only the internally leaking pipes that caused the high damp readings.

My plan of action is to do the following:

- Hack off pebble dash so it ends above new dpc. (with drip end)
- ⁠insert dryzone rods at least 15cm above ground level on external walls
- ⁠replace broken airbrick (picture attached)
- ⁠pipework that caused leak will be replaced
- ⁠Clean out gutters (none seem broken)

Does the above sound like the best plan?

P.s absolute legend - thanks for replying and letting me know about the condensate pipe. I massively appreciate your help.

[dewaltdisney]

I would not be in a hurry to start cutting back the exterior render. You need to firmly establish if it is indeed a rising damp issue caused by bridging. If you have sorted the leaking inside it will take a fair bit of time to dry out. If you have access to a damp reader, they are only £20 on Amazon, you could plot the damp patterns to get a better idea of the problem. With the better weather approaching it will help the drying process and the receding damp pattern will show the likely ingress areas.

DWD

[JordansDIY]

Hi so I took your advice and took damp readings using a dryzone damp meter and it is still showing as high level readings on the lower parts of the internal wall and gradually reduces as it gets higher. The kitchen plaster has been removed and internal pipes have been removed and there’s been no running water in the house for 4 months now so that should have eliminated that as the cause right?

Is the next steps now to remove the pebbledash as I can’t seem to identify other possible causes other than the bridging.

[dewaltdisney]

My gut tells me it is not a rising damp issue as if the DPC was bridged the damp would creep up the wall from the biggest ingress points. My son had the classic washing machine feed pipe washer leak and the wall was saturated from a drip. This has taken some months to dry out in a heated house. It is quite possible that the water from the pipe leak is prevented from draining out by the DPC and that is causing the damp to remain in the low areas above the DPC. Classic damp is usually in spike patterns. I take it the house is empty as a cold house will not help drying out so you can see the problem.

DWD

[JordansDIY]

I’m needing to redecorate and start plastering the kitchen in the next 3 weeks. Is there any plan of action you’d recommend? I could get a dehumidifier to help the drying process. Am just wondering the downsides if I did take off the pebbledash and put the dpc at the right height externally just to cover all bases considering how soon I want to redecorate and start living in the house again. If it was the leaky water pipes that caused it then it should eventually dry out right. and if it was bridging and i take off the pebbledash then that should solve it too?

Would I need to first wait for the wall to fully dry out before replastering?

[dewaltdisney]

It is difficult to advise without seeing it. I would trace the damp around the pipe leaks and look for a pattern. You could be right about bridging but I do not feel that is the cause of this damp. I think in your mind you have settled on the DPC being faulty so it would probably be an idea to chop back a bit of the external wall and test the readings below and above the DPC to get an idea. With plastering a dry wall will suck all the water out of the plaster quite quickly so that is why the wall is sealed with a diluted PVA first to allow the plaster to be worked. A degree of dampness will not be too much of an issue but a saturated wall would. Certainly, if you can get some heat into the kitchen and a humidifier it will at least indicate if it is drying out.

DWD