Crawl Space Joists Mold Wet or Dry rot critters?

Hi All,

Found this site thru a google search. I am not an inspector so I hope I am allowed to post here. I apologize in advance if not.

I have a two foot high crawl space addition which I sealed the vents up winter of 2008. Later on, after further research, I realized I need to seal it up completely with pink board & a vapor barrier. In summer I only got to pink boarding & foaming 1/2 of rim joists in 25 x 13.5 addition in spring of 2009. Has concrete block wall and 2" concrete on floor, with batt insulation facing to subfloor. Problem was my back gave out and I did not finish the job. Shame on me I got mold growth on the joists due to very high summer humidity levels in the CS which are 70% in summer and only 40% in the winter. I have resumed the job just recently, so am cleaning up the joists with 20% clorox/water mixture. Unfortunately, I found the joists look shredded and attacked. I can’t be sure if it is wet rot, dry rot, or critters. Have stuck a screwdriver in joists and so far pretty strong. This damage has occurred probably over two summers. Not sure where to begin. Do you think a santa fe humidifier kept at 40% will solve the problem after I clean up all the joist molding. Will it just die without the humidity.
Here are some scary pics that I would greatly appreciate anyone’s input on. Thank you in advance & good karma to you!


Hello, I’m not an expert in this area but a few tips might help you figure out what to do. For one I would use a cleaner made for mold. They sell it in any paint department at major hardware stores. The clorox can evaporate sooner than the water. Your then just adding more water. The mold you getting may have been in the wood from milling. The issue is when the moisture content of the wood gets over 19%. That’s when the mold grows. So if you can keep it below that your mold can’t grow.

So if I can keep the crawls space at 40% humidity always, the wood moisture level would drop down and no further growth would occur. Have been cleaning the mold myself with the bleach mixture, wearing a chemical mask, goggles & gloves. AM a little afraid to use some of the other stuff. We are in in a tight situation financially since only one employed currently where there used to be two incomes. I wish I could pay someone to do this, it is hard work. My hats off to the guys that do this work in such confined quarters.

By looking at your pictures I have seen lumber in stores around here that look like that. I did see some questionable pieces, maybe your problem is not as bad as you think it is

I’m with David. The lumber was probably like that when installed and I don’t believe there’s any action required on your part.

I don’t see much of a mold issue there, what I see is a poor lumber grading quality. A lot of wane on the lumber and edge damage.
Some staining, but nothing alarming.

As was mentioned, monitor the lumber content for moisture readings under 19% and make sure a vapor barrier is intact on the ground with taped joints and maintain humidity levels under 50% when possible. :slight_smile:

65-70% longterm summer humidity will encourage mould growth. Possibly the exterior needs more air sealing to stop high RH warm air from entering.

A standard dehumidifier may be insurance against the high RH in the summer + a soil moisture barrier already mentioned. The winter RH is fine.

Do an encapsulated system and be done with it.

You guys in NC got lots of $$$$$$? :p;-) 3-4 " of foam spray here runs $4+ /sq ft here.

Would be better way to do it if $$$ was available. Since some work was already done; might be able to spray over the foam board at the rim joist with 1"+ to get much better airseal and then do the exposed concrete walls with the 3-4"

Marcel… Two questions… what is “wane” and what’s this about you being on a ship?

Hi Kenton.

Wane= The presence of bark or lack of wood from any cause on the edge or corner of a piece of wood.

The original rounded surface of a log, with or without bark, on any face or edge of sawn timber.

The absence of fiber on the edge of a piece of lumber.

I am working as a Carpenter on a Naval Destroyer at Bath Iron Works (General Dynamics).

The last two years I have worked only 4 months with my Commercial Building employer that I have been with for the past 40 years. Never seen this happen.

Building and jobs just died.
Company is still finding a little work to keep a couple of his Brothers working, but no employees left for me to supervise, so I was out of Health Insurance and unemployment benifets and had to take the first job that came up.

Believe me, I am quite outside my element, their is no wood on a ship. :wink:

It does have benifets I need, but don’t pay crap. Lost 1/3 of what I was making.

I do still have the Company Truck and some tools to get by on weekends and he told me not to worry about it for now, it is the least he can do is what he said.

He knows I am looking elsewhere for Building Superintendent jobs and said go for it cause their is nothing in site.

Really sucks. Hopefully things turn around. I am not getting any younger.

Applying for jobs at 60 is not always helpful.

Hope the definition above is of some help. :slight_smile: