Efflorescence in crawl space - old or new, will this need work (roofing, drains)

[IDontKnowWhyIDidIt]

I had inspection of a home I am planning to bid for. This is in the hot Seattle market.

This is what the inspector wrote:

Efflorescense in crawl space
Crawl space: "There is efflorescence water staining in areas around the foundation. This is caused by water infiltration. It is dry at time of inspection and is difficult to tell when or how it occurred, further evaluation would be needed. Could have happened at time of construction."

The inspector said that it has been raining like crazy past month and there was no evidence of water or moisture hence He believes if there was a leak he would have seen some water or at least some moisture. Hence he believes its old.

Considering what the inspector said how concerned should I be? I am getting a sense that this is an old issue and is not concerning now, because there was no moisture even with the rain that we had.

[JonahWicky]

Efflorescence is caused by water coming through the wall and leeching out salts in the concrete, block or brick. if the inspector didn't see any active leaks, especially after recent rains, I wouldn't be too concerned about it. The correct fix is to excavate the outside of the walls and waterproof. Treating it from the inside is basically covering up the problem.

[Ralph_Kirk]

Originally Posted by JonahWicky

Efflorescence is caused by water coming through the wall and leeching out salts in the concrete, block or brick. if the inspector didn't see any active leaks, especially after recent rains, I wouldn't be too concerned about it. The correct fix is to excavate the outside of the walls and waterproof. Treating it from the inside is basically covering up the problem.

I agree with this. One thing I'd note is whether the house has proper rain drainage away from the foundation--effective gutters and downspouts that move the water six or more feet from the house (the inspector should have noted if the drainage system is poor). It's possible that at one time drainage was poor--causing the efflorescence--and that's been corrected.


How old is the house? Concrete block is a porous material, and constant moisture on one side will migrate through it if not blocked by a waterproof layer or substance. Really effective modern exterior waterproofing methods are relatively recent (in building science generations) and may not have been in use when an old house was constructed. But as long as the rate of migration is low enough and the interior humidity is low enough that liquid water never forms on the interior walls, it's not a problem in an old house.

[IDontKnowWhyIDidIt]

Thank You and to answer your questions.

The house was constructed in 2000. So relatively modern.

The house has a below grade downspout (see first pic below), hence if there is an issue its probably because of below the grown drainage. But I am guessing the inspector would have seen some wetness after heavy October rain.

What makes me a little suspicious is how the sellers have taped the downspouts instead of putting adapters which are cheap. Could they be hiding something there? Please see the pics below.

[Ralph_Kirk]

Is that grate where the downspout discharges? That's too close to the house (and I can't tell the slope from the house).


The purpose of a downspout adapter would be to provide a cleanout and another grate against debris (leaves, roofing gravel) that enter the downspout from the gutter.

[JonahWicky]

Do you know where the downspouts drain to? If the water is just going into the ground, it will find it's way inside pretty easily. Try running a hose into the underground drains to see if they're connected to something that carries the water away.

[Jonathan Ellis]

Also take a closer look at the fresh mulch. Sometimes mulch is thrown down to improve the appearance of the grade surrounding the home. If the soil underneath slopes toward the foundation, the mulch obscures the problem. Water will sift through the mulch and follow the grade of the soil beneath, possibly toward the foundation. The soil beneath the mulch needs to have proper grading.
The area drain in the photo should raise some questions also. This may be an attempt to get standing water out of the area. Any significant rain would probably clog the area drain with the surrounding mulch. I would recommend closer evaluation of the drainage in that area.