Rising Damp - Fact or Fiction?

[JP_]

Surely a brick wall right next to a water source should have damp rising up it?

Maybe the water is evaporating on the external surface due to air flow, sunshine etc?

Are you suggesting that none of that water can penetrate those walls?

 

[JP_]

most of the lower floors are unused because of damp

Much as I suspected!

 

[George_engineer]

I'm sure cowboys do this, but not seen anybody here suggest that.

I've experienced it - my mum got a damp 'specialist' to look at their house. They wanted to inject chemical above a perfectly serviceable slate DPC. Madness.

It's no good having people with chemicals to sell to survey your house. And they need to have an understanding of material science and old buildings.

The issues the had was:
- gypsum and cement plasters
- high ground levels on some walls
- concrete hardstanding bouncing rain onto the walls
- insufficient heating
- new double glazed windows with no trickle vents
- no extractor fans

All classic reasons for damp problems yet the chemical man thought they should inject bricks. It's utterly crazy.

 

[opps]

Did DPC's exist in the 16th century?

If "yes" they must have been needed. If "no", then they must not have been needed.

View attachment 276905

From the following

There is no doubt that rising damp by capillary action, caused by the progressive rise in the water level, is the main reason why the entire fabric of the city (around 15,000 buildings) is degrading.

 

[opps]

I've experienced it - my mum got a damp 'specialist' to look at their house. They wanted to inject chemical above a perfectly serviceable slate DPC. Madness.

It's no good having people with chemicals to sell to survey your house. And they need to have an understanding of material science and old buildings.

The issues the had was:
- gypsum and cement plasters
- high ground levels on some walls
- concrete hardstanding bouncing rain onto the walls
- insufficient heating
- new double glazed windows with no trickle vents
- no extractor fans

All classic reasons for damp problems yet the chemical man thought they should inject bricks. It's utterly crazy.

How do you service a slate DPC? Do you pull out a section at a time and replace it, and if yes how do you bed the mortar in fully?

 

[George_engineer]

How do you service a slate DPC? Do you pull out a section at a time and replace it, and if yes how do you bed the mortar in fully?

I mean the slate dpc was absolutely fine.

Serviceable
adjective
1. fulfilling its function adequately; usable.

 

[wessex101]

You don't need to go in. Look at the brick walls!

No stain, no lichen, no salt stain, no tide mark. No damp by the look of it. Why not? Surely a brick wall right next to a water source should have damp rising up it?

Maybe all those buildings in the photo have lovely injection DPC's?

 

[opps]

I mean the slate dpc was absolutely fine.

Serviceable
adjective
1. fulfilling its function adequately; usable.

But slate can crack.

 

[George_engineer]

But slate can crack.

Why would it crack? I've told you - there were clear and obvious reasons for the damp which the 'specialist' completely ignored. I've remedied all of them and have no damp problems. Dpc never touched.

A slate dpc is formed from two layers of slate bedded in mortar.

 

[JP_]

All classic reasons for damp problems yet the chemical man thought they should inject bricks. It's utterly crazy.

Well, at least they didn't suggest filling in all air vents as a method to stop moisture getting under the floor!
Yes, that's what happened to my house - previous owner must have had some really bad advice, and probably why they sold it in the end.

 

[opps]

Why would it crack? I've told you - there were clear and obvious reasons for the damp which the 'specialist' completely ignored. I've remedied all of them and have no damp problems. Dpc never touched.

A slate dpc is formed from two layers of slate bedded in mortar.

I am not doubting that they were trying to hard sell a product that wasn't required but houses do move. I work in London, as the clay dries out it contracts and the slate can fracture.

 

[George_engineer]

I am not doubting that they were trying to hard sell a product that wasn't required but houses do move. I work in London, as the clay dries out it contracts and the slate can fracture.

OK. In that case I'd be more concerned about rain water coming through the crack in the wall than rising damp. Presumably a crack would destroy any alleged capillary action.

When I've more free time I'll do my own experiment with old bricks on whether water can actually seep up beyond a discontinuity such as a mortar joint.

 

[opps]

OK. In that case I'd be more concerned about rain water coming through the crack in the wall than rising damp. Presumably a crack would destroy any alleged capillary action.

When I've more free time I'll do my own experiment with old bricks on whether water can actually seep up beyond a discontinuity such as a mortar joint.

Fair call.

All I can say is that I have worked in houses where the only remedial work was drill and inject. It worked.

Please do report back

 

[^woody^]

Injection does work where the moisture is not under pressure, or where the wall components are otherwise suitable for the voids and capillaries to be treated.

 

[^woody^]

Are you suggesting that none of that water can penetrate those walls?

The discussion is about rising damp, not sideways damp.

I think we can all agree that water can travel sideways.