How Much Moisture in Brickwork at Ground Level?

[Surrey1972]

I have taken some moisture readings on our external brickwork and would appreciate some advice. The bricks that are at ground level are showing moisture levels at 19 - 26%. The next layer up are at 5 - 14%. Both these layers are below the DPC. The layers above are showing are 0 - 5%.
Inside the house there are no signs of damp. Internal humidity does increase to around 70% in heavy rain but returns to 40 - 50% a day or so later.
Wondering if these readings are in normal range or may be an indication that there is an issue?
Thanks

 

[Deluks]

It's normal for the bricks below the dpc to be wet, as they are in contact with the ground.
That's the whole point of the dpc, to isolate the wet ground contact bricks from the ones above the dpc which make up your walls.

Presumably you close the windows when it's raining, and possibly put the heating on? This will increase the RH.

 

[Surrey1972]

Hi Deluks
Thanks for the reply, that is reassuring.

Yes, when it is raining the windows are closed, with trickle vents open. Heating stays set for 20degC downstairs and 18degC upstairs, coming on automatically when the room temps are below this.

 

[Harry Bloomfield]

Wondering if these readings are in normal range or may be an indication that there is an issue?

All quite normal.

 

[Surrey1972]

Thanks Harry

 

[noseall]

I have taken some moisture readings on our external brickwork and would appreciate some advice. The bricks that are at ground level are showing moisture levels at 19 - 26%. The next layer up are at 5 - 14%. Both these layers are below the DPC. The layers above are showing are 0 - 5%.
Inside the house there are no signs of damp. Internal humidity does increase to around 70% in heavy rain but returns to 40 - 50% a day or so later.
Wondering if these readings are in normal range or may be an indication that there is an issue?
Thanks

Below DPC? It’s permanently damp down there and is meant to be. Zero point taking meter readings below DPC.

 

[Surrey1972]

Thanks Noseall.
I had read online that anything above 20% in bricks below the DPC was an indicator of DPC failure, hence my concern. Would you say that isn’t the case?

 

[Ivor Windybottom]

What have you read and where? It's complete rubbish. They're sitting in the soil, they can get as wet as a stone thrown in a puddle!

Why would you think that a failed DPC could make the bricks below it wetter? There's no logic.

 

[noseall]

Thanks Noseall.
I had read online that anything above 20% in bricks below the DPC was an indicator of DPC failure, hence my concern. Would you say that isn’t the case?

Eh? What the actual f….

 

[endecotp]

I had read online

Don’t believe anything that you read on the internet.

Oh hang on a minute…….

 

[Notch7]

The bricks that are at ground level are showing moisture levels at 19 - 26%.

the moisture content will be dependant on the porosity of the brick and what the situation is...an aspect facing the weather which soil up against it will be way higher than a low porosity engineering brick with a well drained gravel strip next to it

the only thing that matters is the whether the DPC is functioning and whether the cavity is working properly.

humidity level increasing to 70% when weather is raining and wet will be due to ventilation

I would suggest it may be the location of your humidity meter, is it near to a draught at all?


I have a humidity meter on a piano in the lounge / diner and that stays fairly consistent at around 50% to 60% all the time not increasing much during wet weather -if anything its higher in the summer when the doors open a lot.