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Water Coming through above-ground Porch Slab

Posted by wetslabjeff (My Page) on
Fri, Jan 11, 13 at 16:52

Help needed please for new issue. We live on a hill and have water on our porch after hard rain.

This is very interesting as:

1. the concrete slab is 1.5' above ground on the high side and 2.5' above ground on low side.

2. the basement sump has no water in it at all.

3. the problem is much worse than ever and the only difference is I recently painted the concrete porch floor.

Follow-Up Postings:

RE: Water Coming through above-ground Porch Slab

When it rains, you have water on your porch. And this is a problem? What am I missing?

A picture always helps.

RE: Water Coming through above-ground Porch Slab

I trust wetslabjeff won't mind me posting this direct message he sent me so we can get other opinions:

Also, I can dry the floor and it will get wet again. Perfect droplets form over all its surface. It's drizzling now. Slow and steady with no wind and no water being blown in through the screen. I've lived here for 8 years and have never seen it this bad. Before the new paint, the floor would get damp during wet days but nothing like this. It's like it's been squirted with a hose.

It's not rain water. Bricks built into the floor surrounding the slab are bone dry. The furniture is dry. It has not blown in. This is a new problem somehow related to new floor paint.

If the paint is less permeable than the concrete, the misting that was formerly absorbed by the concrete now sits on the surface as water droplets. The bricks that seem dry are also very absorbent.

There might also be condensation on the paint surface, just as it will form on a car overnight while the concrete walkways appear dry.

If the porch slab wasn't poured over a vapour barrier, you will also have moisture drive from below going through the slab. Putting the paint on the surface may be making it more visible. If it's moisture drive it will eventually lift off paint that isn't permeable.

Note water running off freshly-painted porch.

This post was edited by worthy on Sat, Jan 12, 13 at 13:05

RE: Water Coming through above-ground Porch Slab

It IS lifting the paint off. What can I do? It was so much better before the new paint.

Wait for nature to take its course. Or help it along. Then, if you still want a change, you can use the most common alternatives--tile or natural stone (preferably on an uncoupling membrane) or indoor/outdoor carpet.

The moisture drive is what also throws a monkey wrench into so many garage floor painting projects.

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