im fairly certain I have a rising damp issue on an external wall. Despite the dubious nature of this type of damp in some quarters I’m confident it’s from the ground because:

-Damp showing up to 1m height

<span style=”font-size: 0.8rem;”>-external of affected wall is built over so doesn’t receive rainfall (it’s the alleyway of a Victorian terrace)</span>

-no internal pipe work that could be leaking

– I’ve lifted some flags external to the affected wall and had a little dig –  the ground at surface level is virtually bone dry (as you’d expect for a covered alleyway)

so my question is: are the DIY treatments worthwhile? I’m thinking of the dry zone proofing rods inserted into the mortar followed by suitable re plastering (lime plaster or cement based plaster with additive for damp effected walls)

Or should I bite the bullet and get a pro in to do the snake oil professional treatment? (High pressure injection of the mortar / bricks)

The injection thing doesn’t work.
Find out where the water is coming from and stop that.
A french drain or similar to keep the wall footings dry can help.

APF

From my investigative dig I’m not certain a fence drain will help?

The ground adjacent to the footings was dry  – I’m not sure what a French drain would achieve here?

Could it be rising from the ground the footings are sat on? My understanding of this age of property is that they weren’t built on foundations – but directly on the soil \ ground

I’m firmly in the sceptics camp. If the ground is dry then it seems unlikely its coming from the ground. I’d keep looking for another cause.

Further reading:

http://www.askjeff.co.uk/rising-damp/

https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html

https://www.heritage-house.org/damp-and-condensation/what-is-rising-damp.html

Toolstation sell tubes of damp proofer for about £15. You obviously need to drill the bricks to use it.

“I’m firmly in the sceptics camp. If the ground is dry then it seems unlikely its coming from the ground. I’d keep looking for another cause.”

so where could it be coming from? Bare in mind I know where all the pipe work is in this house and there is nothing near the affected wall – above or below. And the damp stops at approx 1m height, indicating it’s coming from the ground.

Not being provocative – just stumped as to the root cause

Solid or cavity wall? Does it have a slate dpc. Our (Edwardian) house had a damp issue caused by the morter aging blocking the cavities and bridging the dpc. Clearing the cavity fixed it.

Water has a way of travelling a fair distance from source to site of problem. We’ve got an old house, concrete floors laid directly onto earth. Rainwater coming down a poorly pointed external wall was finding its way through the wall, along approx 4m of concrete floor and manifesting in wet rot of a doorframe at the back of the house. Only discovered (and rectified) the problem when I renovated the kitchen.

I’d be checking for leaky pipes all round the house.

You can get the plaster analysed for salt content which helps decide whether it is rising damp.

Solid wall? Check the ground level outside v inside, if external is higher then I’d suspect condensation. Window and door openings give a good internal/external gauge </egg-sucking>

It’s a solid wall. No slate DPC.

Thabks for the replies so far

Is there a chimney nearby? salts in brickwork from burning coal, i’m a rising damp sceptic, there is a cause and there will be a remedy, but it’s unlikely chemical damp proofing will be that remedy.

Has there been any plastering done in gypsum plaster or rendering in poltland cement? Pointing in Portland?

Also what is s the floor?