Question
Hi Sean,

I put some weed retardant material down on the side of the house between the house and the sidewalk. I noticed that it's filled up with water after the rain.  The water doesn't go through the weed retardant material very well.  This is right next to the house.

I bought some pebbles to pour in that area.  Do i just dump the pebbles in the area, or is there something else i should be doing with "drainage" first?

Previously water was just absorbed into the dirt. Pretty sure anyway.

Looking forward to hearing from you,
Wayne

Answer
First, unfortunately I have to tell you that most weed mats don't work after a year or two. No reputable commercial landscape company will use or install them. They are just cheap marketing products that sell well but don't really work very long. The problem is that after a few years organic material that has fallen on top of the mat (leaves, dust, etc.) begins to breakdown and become soil. This provides a place for the weeds to root on the surface of the mat. Then when you go to pull those weeds up you end up pulling up the mat because the roots have grown down through it. This is why we often see landscape beds where the weed mat is exposed.
The best way to stop weeds is a heavy layer, a minimum of 4" thick of mulch in the form of shredded wood, bark or pinestraw depending on where you reside. Also you must get the weeds under control by spray or pulling. Once you eliminate the seed sources for a good couple of years in a row it will drastically cut down on your weed problem thereafter. You may also consider applying a 'pre-emergent' weed preventative in your beds.

But if you are dead set on keeping your weed mat, there is no reason you can not cover it with stone. If the mat is the kind designed to allow water to pass you will notice that the water infiltration is going to be slower than it was without the mat, that would be logical. However, if you mat is a sheet of black plastic, don't do it! Plastic will hold water and simply become a organic puddle off ooze, causing mold and mildew to grow on your house.
If the area is to flat and the water is standing for more than a few hours then you will need to re-grade the area to drain away from your house or install a drain system.
Best of  luck.


Sean J Murphy, LA,ISA, LEED AP
Please check out my blogs and articles on landscape topics like this on my websites.
http://www.seanjmurphy.com
http://amenityarchitects.com