New Slab

[gofast]

Slab has been down now for 45 days it keeps turning brown when it rains there is a big oak tree near by 10 feet is it getting the color from the tree ?
It has no sealer or anything on it waiting on walls and roof to go up before sealing or epoxy. Whats best to pressure wash with?

 

[kd3pc]

at 45 days, I would be gentle and use a stiff bristle shop floor brush and some mild detergent in water on part of the spot to see if it comes up, or has stained from something near by, if there are lots of leaves then perhaps it is the tree, but I would not think the "tree" would cause the brown water, sooner think some bio stuff growing.

Personally I would take a sample in a quart jar, and put a teaspoon of clorox in it to see if it clears the test sample.

...pressure washer may be a little powerful and IF there is any scale or weak spots - it will find them quickly

 

[DougWil]

Yes Oak leaves, acorns and branches leach tannin out of them, it is acidic and slightly corrosive.

Maybe you should put up a hide tannery on your slab?

 

[gofast]

Hopefully will have walls and roof this week