Mystery stains on deck

[ericandcrystalh]

Hello TFP! We have an in ground chlorine pool, just finished construction in the Houston, TX area. We’ve had some heavy rain and we are noticing stains on the deck that look like it’s washing from the travertine coping onto the spray decking. The stains do not scrub off. Any idea what they are? We’ve just reached out to our PB as well but wanted to see if anyone here has any ideas. Thanks!

 

[Texas Splash]

If it's run-off from the area it could be just about anything. I would first try rubbing a Vitamin C tablet on it to see if it's iron. If that doesn't work, try rubbing some dry acid on it if you have some to see if it's copper. Maybe the rains are washing metal content down to the decking from nearby dirt, mulch, etc.

 

[ericandcrystalh]

After about a week of nonstop rain it’s finally stopped here in Houston. Looks like the stain probably is iron thats being leeched out of voids in the travertine where water got in during the rain. Any idea how to stop this? In this spot, I can wipe the water and new water comes up through a hole spot in the tile. Should I get the water out and plug the hole with some silicone or something? I’d like to not have to repeatedly clean up iron stains after every rain. PB is still going to come check it out but there are a few tiles with some natural holes where I’m sure it’s normal for some water to get in. This particular spot must be a bigger void or something...

 

[Texas Splash]

I see what you mean. Normally when we seal we think of doing it to protect the surface from stuff on top not below. In this case, perhaps it's good the water pressure has a place to "release". I don't know. I'd wait to see what your builder has to say since he's most familiar with the water table and characteristics of your soil. Let us know though and we can keep this discussion going for others who may have experienced the same thing.