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What is the best way forward to resolve damp issues?

Postby ljrc » Tue Dec 14, 2021 8:41 am

Hello,

Thank you for reading my post. I'm looking for opinions on my problem with damp detailed below?

I live in a small semi-detached Victorian terrace (about 120 years old).

We 100% have an issue with damp on the wall in our living room at the front of the house (we have seen mold on the inside at the bottom of the wall above the skirting).

I've had three people come over and two of them have said the problem is the damaged strip of concrete plinth around the outside of the two external walls - one person said this is contributing to a problem with rising damp. To fix it they have suggested injecting the wall with some sort of damp-proof cream, mending some of the pointing in the brickwork at the front of the house, and then rebuilding the plinth. They used a Protimeter to take some readings on the wall.

I then had one guy over who basically said that all of the above is BS! He didn't use the same meter as the other two and instead had a thermal imaging camera. He said that the problem with damp is in the brickwork itself. He has suggested fixing any damaged pointing and then applying a product called ProPerla to the outside of the house that will prevent any moisture from getting into the brickwork whilst allowing the current moisture in the brickwork to breathe out over 2 to 3 months.

I've attached some images i've taken.

I'm getting a few more quotes in to see what they all say and compare costs but as I said just interested in people's opinions on the problem and whether the advice I have had sounds legit.......im leaning towards the solution using ProPerla.

Cheers
Louis
Attachments
E. Outside of property dimensions_5.png
D. Side of property_4.png
C. Front of property_3.png
B. Front of property_2.png
A. Front of property_1.png
ljrc
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Postby stoneyboy » Wed Dec 15, 2021 10:22 pm

Hi ljrc,
I would suggest that your problems are due to the presence of the plinth which has been fitted against the lower courses of bricks. There is probably a slate DPC in the wall and the plinth is bridging this, causing rising/penetrating damp.
I suggest you cut back the block patio and remove the plinth so the lower bricks can dry out.
Regards S
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Postby ljrc » Thu Dec 16, 2021 6:46 am

Thank you for the reply. Yes what you say is what i've now established after speaking to several people.

I had a chat with a family friend in the building trade and this was his take on it.

The rendered plinth has breached the DPC. If you look at the bottom left of the picture 'A. Front of property_1' you can see the height of the original rendered plinth (roughly 150mm). The remainder of the plinth is higher, and above the slate DPC which sits at around the 150mm.

He also highlighted that the third air brick on the right hand side is higher than the other two air bricks and is breaching the DPC as well. He suggests replacing the third air brick so that it aligns with the other two and sits below the 150mm DPC and hacking off the plinth and replacing it with a new plinth at 150mm OR installing a tall plinth up to the window sill for aesthetic reasons in order to cover the dark brickwork on the left and right to the front of the property (using a stop bead where the DPC is so that the new plinth does not breach it).

He also recommends removing the last row of bricks from the driveway as ideally this should not but-up to the plinth since rain water will be currently splashing back onto the plinth, the brickwork and over/inside the air bricks. In place of this last row of bricks he suggests laying pebbles so that rain water cannot splash up when it hits the ground.

The consideration now is whether I could give this all a go myself. One person has recommended injecting a chemical DPC which I think is sensible since the original DPC is breached and very old and so I think it might be permanently compromised. I THINK I could do this but its the rendering that I think I might really struggle with.....
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Postby stoneyboy » Thu Dec 16, 2021 9:08 pm

Hi ljrc,
Do not leave the “plinth” in place - remove it completely. Once the row of pavers next to the plinth have been removed you will then have a trench next to the wall with its bottom some 100mm lower than the drive level. Leave it like this until mid next summer and depending on the amount of drying out that takes place you could then consider injecting a DPC. Bear in mind that with the age of your property it’s probably lime mortar and drilling into the bricks may be counter productive.
Regards S
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Postby ljrc » Thu Dec 16, 2021 10:07 pm

Thank you for your help. Would removing the plinth and the last row of pavers of the drive to expose the brickwork not cause more problems when it rains if I do leave it until the summer?

Thanks
Louis
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