Reclaimed bricks, 21% moisture in them, Si brand, usable or better to wait until moisture level drops?

[finlaand]

Hi there, picked up 200 of these bricks from reclamation yard, Si logo inside a club, nice looking bricks if that is a thing
... . Anyway just checked them and they are c21% on moisture meter. I have them inside garage for now, a dehumidifier on.. What percentage would I need that to drop to to use them? A few weeks now before temps rise anyway.

 

[John D v2.0]

What makes you think they are not usable? What are you going to use them for?

If it's a cement mortar wall I would have thought they would be fine as long as they aren't dripping.
The 21% is meaningless except as a relative measure between the same bricks. You could put one in the oven after weighing it on a very low temperature for a day and then weight it again to get an idea of moisture content if it's important to you.

 

[finlaand]

Side wall for house/part... Wasn't sure if moisture made difference hence the ask

. If doesn't ill just use them in 2 weeks

Any ideas what the logo meant?

 

[Mr Chibs]

Why have you got a X on your slipper... is it to tell which is right and left?

 

[finlaand]

Two boys with identical sized slippers, so your near

 

[jeds]

Moisture meters can't read MC of bricks. I'd use them as they are - don't dry them too much.

 

[finlaand]

OK ta

 

[RonnyRaygun]

Bricks expand for some time (years) after they leave the kiln, due to the slow absorption of moisture. This is why we put movement joints in long masonry panels.

Reclaimed bricks should be at pretty much maximum moisture content (21% is pretty high), so expansion shouldn't be an issue. If they are to be used externally the moisture content should stay pretty much where it is, but if they are going to be used internally there is some risk of contraction that could lead to cracking as the moisture content reduces.

Higher moisture content can also lead to lower flexural strength, which can be an issue in retaining walls and high free standing walls, although BS5628 gives the same flexural strength for any bricks with water absorption of over 12%.

 

[George_engineer]

Moisture meters can't read MC of bricks. I'd use them as they are - don't dry them too much.

Yeah - at best it'll be the surface level reading. Inside the brick is likely much lower.

 

[stuart45]

Some of the older, more porous bricks are better off being a bit damp when laid, as this way they don't suck too much water out off the mortar.
General rule of thumb years ago for bricks was damped down so the inner of the brick was damp, but the surface was dry for a bit of suction, and laitance didn't run over the facework.