Garage damp/moisture at foot of wall (Ed)

[BojanL]

Hi there,

Single skin breeze block garage, rendered outside. Leaking tiny bit on the bottom between floor and wall. Double block column sometimes wet which creates white fluffy mold.

What would be the solution here?

Cheers!

 

[JohnD]

Looks like rain falling on exposed slab edge. No drip or gap in render. Might be puddle outside. Stand back and take pics showing roof, gutter, downpipe and drain please.

 

[BojanL]

There is a puddle on the paving by the wall on one side - slight ground slope making it worse. Guttering is all good except there is no guttering at the back where the problem is present as well. Side with the windows and gravel is fine.

 

[^woody^]

Having it properly rendered would help

 

[JohnD]

Are the paving slabs set in concrete?

Or could you lift them, lower the ground level, and reset them sloping away from the building?

Is there a DPC?

 

[JohnD]

.... Guttering is all good except there is no guttering at the back where the problem is present as well....

Does water drip off the roof edge?

 

[BojanL]

Are the paving slabs set in concrete?

Or could you lift them, lower the ground level, and reset them sloping away from the building?

Is there a DPC?

Paving slabs are just on the ground, I could lower the ground and reset the sloping.

DPC is 1 course above ground level, not sure if there is any membrane in the slab.

 

[BojanL]

Does water drip off the roof edge?

Yes, some. Ground is above the slab level on that side so I guess best to lower it and see if it resolves the issue.

You wouldn't put any slurry, liquid rubber or membrane sheet on the edge externally?

 

[JohnD]

No, that will make damp worse by preventing it evaporating out.

 

[BojanL]

Having it properly rendered would help

What do you mean by properly? There is no problem on the side of the windows and gravel.

 

[BojanL]

No, that will make damp worse by preventing it evaporating out.

Not sure if I understand - wouldn't an exterior barrier keep water outside and prevent damp from happening?

 

[JohnD]

If you can prevent rain falling on it, that will help. Exposure to air will help it dry.

If the slab is in contact with the ground, it will always be damp. Porous building materials in contact with damp ground lose water by evaporation, and become dry at the point where evaporation exceeds uptake. Good, clean modern brickwork with cement mortar and no plaster or render, is usually dry after a couple of courses.

 

[BojanL]

If you can prevent rain falling on it, that will help. Exposure to air will help it dry.

If the slab is in contact with the ground, it will always be damp. Porous building materials in contact with damp ground lose water by evaporation, and become dry at the point where evaporation exceeds uptake. Good, clean modern brickwork with cement mortar and no plaster or render, is usually dry after a couple of courses.

So basically lowering ground to expose the slab would be first thing to try.
Thanks!

 

[JohnD]

chipping away the render a few inches above the ground or slab will prevent it absorbing water.

professionals use a metal strip bead to make a drip edge so rain falls off