# Fibrous growth on basement walls **URL:** \ **Category:** Factual Questions\ **Created:** [August 8, 2016, 4:11pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146 "2016-08-08T16:11:56Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![somepumpkin](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@somepumpkin](https://boards.straightdope.com/u/somepumpkin)\ **Post date:** [August 8, 2016, 4:11pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/1 "2016-08-08T16:11:56Z")
Hi everyone. We just moved into a new house with a large, great, unfinished basement. However, something that’s not so great about it is this “growth” on some of the walls. The photos aren’t that detailed, so I’ll describe it, too. It appears to be \*clear \*fibres, just under 1cm long, coming out of the brick. They are easily brushed away. I’ve not studied them closely enough to determine how soon (or if) they return. You can see they are damaging the paint, too. Photos: [https://goo.gl/photos/8JRhtNuk2pRDTfHn8](https://goo.gl/photos/8JRhtNuk2pRDTfHn8) What’s going on? ---
**Author:** ![mozchron](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@mozchron](https://boards.straightdope.com/u/mozchron)\ **Post date:** [August 8, 2016, 4:36pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/2 "2016-08-08T16:36:48Z")
[Efflorescence](https://en.wikipedia.org/wiki/Efflorescence) You have a water issue. You should get it looked at. ---
**Author:** ![Omar\_Little](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omar_little/32/269_2.png) [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)\ **Post date:** [August 8, 2016, 8:59pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/3 "2016-08-08T20:59:04Z")
Agree, past water problems, which normally means future water problems. Age of the house? What part of the country located? ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [August 9, 2016, 4:40am UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/4 "2016-08-09T04:40:22Z")
There should be a waterproof layer of tar or something on the outside of that wall … and now it’s completely buried … bummer. Too expensive to apply now, you’ll just have to do the best you can waterproofing the inside. I’d just scrap and clean the wall and use a good oil-painted paint nice and thick. It will work long enough, perhaps as long as your outside paint. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [August 9, 2016, 4:48am UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/5 "2016-08-09T04:48:57Z")
I agree it is moisture coming in. It is lifting the paint. Also some possible mold growth. There are materials to apply that seal cement walls. But I don’t know if they would work with cinder blocks that you have. Plus, removing the paint completely before application might be very difficult. Before digging around the foundation and waterproofing it from the outside. You could try grading the property to make sure water flows away from the building. Adding surface material around the foundation to direct water away. Like large cement tiles. Improving the gutters and extending the down flow from the gutters farther from the building. The fibrous look can be due to crystallization of various minerals as the seeping water evaporates. They can grow. ---
**Author:** ![davida03801](https://avatars.discourse-cdn.com/v4/letter/d/b5e925/32.png) [@davida03801](https://boards.straightdope.com/u/davida03801)\ **Post date:** [August 9, 2016, 11:41am UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/6 "2016-08-09T11:41:12Z")
Moisture getting into the block. Unfortunate for you the best methods of waterproofing a foundation wall are from the outside to prevent the water getting into the foundation wall, not from the inside. Anything applied to the inside is only a temporary solution or a hiding the problem solution. The water is still in the foundation under hydrostatic pressure and will work it way thru. I had this problem in my last house and this was about 12 years ago, or so. It was on one wall and I had to have a guy come over and dig out the earth, clean up the wall and then we applied the Waterproofing Membrane which was a thick product that comes in rolls that was adhered to the wall and down to the footings. There are two types: asphalt products or bentonite clay products. Also do not confuse Waterproofing and Dampproofing. Those products that come in a bucket and applied like a brushed on paint are Dampproofing products and if you have a severe water problem water will still get through. You will need a waterproofing product. Also once you go that far make sure you drain the water away from the house while your at it. Good luck. ---
**Author:** ![somepumpkin](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@somepumpkin](https://boards.straightdope.com/u/somepumpkin)\ **Post date:** [August 9, 2016, 1:29pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/7 "2016-08-09T13:29:31Z")
Thank you for the detailed replies, everyone. This house was built in the mid-1980s and is located in Wake County, NC. It’s been storming all summer… one of the wettest in recent memory. Though I wasn’t sure about the fluorescence (what it was/is), I was sure about the moisture problem. We had the seller repair some faulty gutters and downspouts before purchase, but i think the water had been pouring long and hard on this part of the foundation. We’ve no water in the basement, but a moisture meter rings 100% near the corner. I added some photos of the back of the house and also the suspected problem area. One (actually many) of the gutters was not working and water had been raining down through the deck. [https://goo.gl/photos/8JRhtNuk2pRDTfHn8](https://goo.gl/photos/8JRhtNuk2pRDTfHn8) ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [August 9, 2016, 3:18pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/8 "2016-08-09T15:18:24Z")
Could be worse. We have a crisis locally in that as many as 1,000 homes built around 2000 are on substandard concrete basements - some mineral in the mix causes breakdown and crumbling after a decade or so. Apparently traces to one quarry, insufficient or ignorant materials testing, contractors long out of business, etc. It’s a huge, really expensive mess. Our home, built in 2002, is not one of them but well could have been. **whew** ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [August 9, 2016, 5:05pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/9 "2016-08-09T17:05:09Z")
I bought a house where the previous owners took care of the downspout issue just before I moved in. They also had the foundation waterproofed. One area ended up leaking again (the weeping tile had busted and got clogged and was ineffective) so I had to get that section dug up and re-done, but otherwise the waterproofing has been good. Anyway, my basement wall in the worst downspout corner looked exactly like yours. I was told it would take a year for it to dry completely, now that the problem had been fixed. They were right. My basement was quite dry within a year and a coat of paint made everything lovely again. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [August 9, 2016, 11:48pm UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/10 "2016-08-09T23:48:40Z")
What you are seeing is the physical manifestation of the tortured souls of the underworld trapped behind that wall trying to push their way out into our realm. I do NOT suggest taking a sledge hammer to this wall. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [August 10, 2016, 12:00am UTC](https://boards.straightdope.com/t/fibrous-growth-on-basement-walls/762146/11 "2016-08-10T00:00:44Z")
While addressing the problem from the outside wall is by far the preferred solution, there are treatments that can be applied on the inside that are supposed to work fairly well, such as [Xypex](http://www.xypex.com/products). I had this done to a part of my garage wall that was prone to substantial water infiltration in rainy weather. It didn’t totally solve the problem but it made a huge difference. –Mark