I decided the first step was measuring the humidity under there so I bought a Honeywell TM005X Wireless Thermo-Hygrometer and put the remote unit under the house. I bought it back in January 2009 and boy was I shocked. The humidity seldom got below 75% even in the winter! As the summer came on and the humidity rose to above 90% I decided I had to do something. It is so humid down there that water condenses on the cold water pipes and drips on the floor.

Completing the plastic covering on the floor (about 20% was uncovered) did nothing. So I went looking for solutions. I found the SmartVent Crawl Space ventilator and after reading their convincing argument that you can’t dry under your house with wet air, I decided to purchase one of their vents. It cost me $315.

It arrived less than 1 week after I ordered it and I installed it the next weekend. I had never removed a crawl space vent before but it turned out to be a pretty easy job. Mine were installed with mortar which I broke out using a long chisel and a hammer. It took me approximately 1/2 hour to prepare the opening to receive the smart vent. The place I chose to install it had an electrical outlet nearby so I was set for power. I used clear caulk to seal around the opening.

I installed it on 20 June 2009. After 2 weeks my crawl space humidity is down to 77% from 92% on the day I installed it. I’ll make a table below to record occasional readings. It has been dry here since I installed it. That, no doubt, is part of the rapid improvement but since I’m not doing any sort of controlled experiment, I’m just going to report what I see.

The SmartVent appears to be well made and runs a clever algorithm. It has two muffin fans, a small circuit card, and a thermometer and humidistat positioned near the front grill. It uses these sensors with the fans off to sample the outside air. If the outside air temperature is above 42 degrees F, it runs one fan for about 15 minutes to pull crawl space air over the temperature and humidity sensor. It then compares the dew point of the outside air with the dew point of the crawl space air. If the dew point outside is lower both fans run to pull wetter crawl space air out so that it will be replaced (through leakage) by dryer outside air. If the outside air is wetter than the inside air, the unit waits.

My sporadic observation of its habits confirm that it is behaving as expected. I’ve seen it running continuously for the last few days while the outside dew point has been low but last week it ran much less because the outside air was very humid.

I’ll try to record some readings here so I can track how it does.

Note: On 14 July 2009 my Honeywell wireless hygrometer died and I replace it with an Oregon Scientific RMR500A. The calibration was clearly different. I calibrated the new one using the damp salt method.

I expect it to become gradually harder for the SmartVent to improve the situation under the house because as it lowers the dew point, there will be fewer times when the outside dew point is lower. But, I hope and expect it to be better than it was.

We bought 2 gallons of epoxy and a “Limestone” gray (this color was a mistake see the update at the bottom) color pack for a total cost of $143. It arrived very quickly via UPS. This is a two-part epoxy with a small container of coloring agent. Both parts are surprisingly thick, like gel. We had prepared with disposable measuring cups expecting to pour the two parts into the disposable mixing buckets we bought. Instead we ended up dipping the contents into plastic drinking cups using plastic spoons.

In the poor before picture (below), you can see I have taped the edges and the drain with blue painters tape and I have a layer of newspaper on the floor outside. The tile is an off white color. It looks two-toned in the photograph because of the poor lighting.

First we mixed the color pack thoroughly into Part A. Then we dipped three cups of part A and one cup of part B into our mixing bucket and stirred for 5 minutes as directed. I was worried about the advertised 30 minute pot life being a problem but the material was easy to work with and did not appear to be setting up over the approximately 30 minutes it took to apply each batch.

We used 3 batches on the first coat applying it with cheap brushes. The good news is that the material is quite thick so we had no problems applying it to the walls; it didn’t run at all. The bad news is the brush strokes really showed and didn’t settle out. On the second coat I used one of those painting pads. That worked much better but I believe the only way to get a really smooth coat would be to spray it on. The surface was tack-free after 24 hours on both coats. It had an oily sheen on it after drying but that was easy to clean off.

The dried material is incredibly hard! The application engineer advised me to remove the blue tape immediately and I did that everywhere except over the drain because I wanted it covered for the second coat. I struggled to cut through the layer of epoxy to remove the tape. I’d advise that you arrange to remove the tape while the epoxy is still wet.

We been using the shower now for about 6 months and it is still leak free. The appearance is far from perfect but I have my glasses off in the shower anyway! My wife seems pleased with it too. Another advantage is we no longer need those ugly anti-slip mats shown in the picture below, the floor has plenty of traction without them.

If you have a leaky shower pan and are too broke or too cheap to do it right, I recommend Epoxy Waterproofer.

Update June 2009 We discovered why showers are never dark colors. Soap film shows up everywhere and is just about impossible to clean. So we repainted the shower White, again using Epoxy Waterproofer. Looks great. My wife did it this time and found she liked working with a sponge best.

• Hannah’s blog of her adventures
• Map on MSN Encarta
• Weather
• Hirabayashi JHS and pictures
• Kanno JHS and some pictures of the school
• Elementary schools

On further examination I found that the tubular shaft was cracked allowing water to enter it and spray out the knob. I soldered the cracks and it seems to work now.

Says “lasts up to 90 days”. What does that mean? The upstairs unit runs an average of 3 hours per day. So replace at 270 hours? The downstairs unit runs 2.3 hours per day, so replace it sooner? That makes no sense.

I’ll check them once per month.

We’re very pleased with it. No false alarms, no misses either. We no longer need a doorbell.

Installed 31 July 2006. Batteries appear to last about 9 months.

Replaced east side battery on 26 January 2007 because of battery defect.
Replaced both batteries on 7 May 2007. Alarm was still working but sounds twice for a single car when the battery is weak.
Replaced east side battery on 2 Feb 2008, was sounding twice.

• 12 March 2006
• 08 June 2006 (too long, filter was failing)
• 13 August 2006 (no sign of failure)
• 22 October 2006
• 20 December 2006
• 3 March 2007
• 5 May 2007
• 15 July 2007 (much less silt than usual)
• 30 September 2007
• 22 December 2007
• 16 March 2008
• 6 June 2008
• 29 July 2008 (pressure switch failed, pump running continuously, probably stirred up extra silt)
• 13 December 2008
• March 2009
• 16 May 2009

Installed 31 October 2005.

• Changed oil, oil filter, air filter 11 November 2006. 19 hours on meter.
• Changed oil, oil filter, air filter, checked plugs, on 17 November 2007. 34 hours on meter after running 4 hours during an outage.
• Changed oil, oil filter, air filter on 15 November 2008. Need to check the plugs. 44 hours on the meter.

Oil filter is Fram PH4967
Air filter is Fram CA101 (not available in stores)
Plugs are RC12YC (2) gap 0.020 inch
Oil is 1.7 quarts of 5W-30 synthetic