What is the best way forward to resolve damp issues?

ljrc · Post by **ljrc** » Tue Dec 14, 2021 8:55 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

London mike 61 · Post by **London mike 61** » Tue Dec 14, 2021 9:50 am

The first thing I would investigate is the drain that collects the water from the down pipe at the side of the house. If somewhere along that drainage pipe it is blocked or collapsed, then all the water has nowhere to go and will sit against the house and eventually cause your damp issues.
The damaged pointing and plinth will also contribute to damp penetrating the property.
Your builders advice sounds sensible but the drain issue needs to be investigated first IMO then go from there.
Here is a video that could mimic your circumstances and help understand some reasons why damp in older properties is a problem.

https://youtu.be/vUM9Iei8Yhg

I’m NOT trade just DIY and I’m just giving my opinion on your problem.

Let us know in due course what remedies cured your problem , we always like feedback so we can help other folk.

Mike

dewaltdisney · Post by **dewaltdisney** » Tue Dec 14, 2021 10:55 am

As Mike says, start top-down. Defective gutters are one of the main damp causes. Have a good look and see if the gutters are clear and there is no rainwater spilling over the edge during rainfall. Then check blocked downpipes. For this to be externally caused damp it will have to have been caused by splash up from the ground, unlikely, or drips from above. The wall construction is a queens bond brickwork which is a solid wall with no cavity. Once moisture is in it is difficult to stop the leech through into the house. Looking at the photos of the damp patches either side of the window I would say that the pattern eliminates rising damp as the patches are above the cable line tacked on.

Be wary of anything that contractors tell you, this is one of the biggest exploitation trades going and they will fill your head with crap to sell their solution which may or may not work. I would wait for the next rainfall and get out to check what is happening.. If you have ladders, check the gutters.

DWD

ljrc · Post by **ljrc** » Tue Dec 14, 2021 11:25 am

Thank you both for your replies. I will certainly check the guttering as a first port of call. It does feel like a minefield as every "tradesman" I have spoken to so far has a slightly different take on what the problem is (and how much they are quoting)

dewaltdisney · Post by **dewaltdisney** » Tue Dec 14, 2021 1:22 pm

Just to give you an idea, a neighbour had rising damp in the wall under his stairs. He had all these specialists in quoting silly money to dig out the slab in the area and do remedial. These were blokes with alleged qualifications. He eventually asked me for an opinion and I had a look. Straight away I suspected a leaking washing machine hose as I had seen it before. The dripping water builds up over time and soaks the slab and creeps and the water will wick out where it can, in this instance the inner wall. Fixed the joint leak by tightening the hose union and after a period the wall dried out and it was all solved for zero cost. The 'specialists' would not have solved the problem just grabbed £5k for a needless job.

So my point is there are a lot of charlatans out there, do not rush into a wonder cure. Evaluate it yourself so you have a good understanding of the issue and you can spot sense and bollockstalk from trades.

DWD

ljrc · Post by **ljrc** » Wed Dec 15, 2021 12:17 pm

Thank you again DWD. 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.

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.

Im still waiting for the next downpour to observe what is happening to rainfall on and against my property, including how the gutters are behaving.

dewaltdisney · Post by **dewaltdisney** » Wed Dec 15, 2021 1:31 pm

That all sounds sensible and easily achieved. I would still do a check on the gutters as planned before proceeding. It does sound like you are on he right track. Good luck sorting it.

DWD

Argyll · Post by **Argyll** » Wed Dec 15, 2021 1:40 pm

I had similar in a house I bought in the 90's. They built the patio over the DPC causing damp. I had to remove the patio and dig a foot deep trench around the back of the house before the mortgage company would release the remainder of the funds. Then we had to get a company in to inject a chemical DPC.

You can now create your own chemical DPC. The Skill Builder channel on YouTube showed how. I wish this was available in my day as I'd have saved a lot of money.

ljrc · Post by **ljrc** » Wed Dec 15, 2021 8:52 pm

Thank you DWD and Argyll. Now I have a good idea of what is required I am hoping I can source a tradesman to complete the works for a reasonable price. I must say, I am part tempted to attempt some of the work myself.....

Someone-Else · Post by **Someone-Else** » Wed Dec 15, 2021 9:01 pm

ljrc wrote: ↑Wed Dec 15, 2021 8:52 pmI must say, I am part tempted to attempt some of the work myself...

If it is as easy as Roger shows, any trades person is going to want a fortune, why not DIY and let us know how you get on? Click here for the stuff roger said

ljrc · Post by **ljrc** » Thu Dec 16, 2021 6:36 am

The damp proof injection, or rods, appears straightforward. Its the rendered plinth that will be most tricky

wes56 · Post by **wes56** » Tue Dec 21, 2021 7:31 pm

You appear to have solid walls which makes it easier for damp to penetrate to the interior side of the wall.
Can you post pics of the interior damp damage, and pics showing all the interior front and side elevations at skirting level?
Plinths are bad news and your plinth looks like its bridging the DPC... So all of your plinths should be removed, and the pointing behind them should be raked out to 20mm and re-pointed.
There's been re-pointing in the past to the front elevation. The re-pointing rake out is shallow, and should be in sand and lime not cement.
Your floor joist tails sitting in the damp wall(s) may be rotting, they should be examined.
The air bricks look to be too high for venting the sub-area?
Have air bricks been installed in the side wall?

Any gullies should be drained, cleaned out, dried off, and examined for cracks. And then water tested for flow.
Water testing for drainage breaks is a simple matter.

If splash from gutters etc was the problem then green algae would be seen below on the ground & the lower walls.

.

sammy.se · Post by **sammy.se** » Thu Dec 23, 2021 12:48 pm

Hi,

I have a similar aged terraced house, and similar issues which I have now solved (well, at least it has been for 2 years so far).

Before you do any new plinth or pointing work, can you confirm your house has a single solid wall, i.e. no cavity, or if it has a cavity?
I'm 90% sure it will be single solid wall with no cavity.

If it is - please please please do not use cement anywhere near it. You need to use lime, both inside and outside on that wall, and a truly breathable paint like limewash or Earthborn claypaint (which I have used and I love it).

Cement and gypsum plaster cause so many problems - moisture gets in but can't get out. Lime let's moisture in and out, and our houses can only stay sound that way.

I have gone through 3 years of pain solving my damp problems and I can share more info with you, but I need some time to type it up.

sammy.se · Post by **sammy.se** » Thu Dec 23, 2021 12:49 pm

BTW, What region are you based?

ljrc · Post by **ljrc** » Fri Dec 31, 2021 6:01 pm

Thank you for everyone's continued advice. I have been away with family for the Christmas so only getting back to this now.

In reply to some of the questions asked:

- I have included 4 more photos showing the inside damp damage and the inside of the exterior walls.

- No air bricks exist in the side wall.

- The walls are single solid walls with no cavity.

- I am based in Croydon, South London.

I will be removing the carpet in the living room to replace with laminate flooring shortly and when I do this I will take the opportunity to inspect the joists below the floorboards (fingers crossed these are not affected by damp/rot).