This model railroad article originally appeared in N-Scale magazine in the May/June 1993 issue. We would like to thank Bob Hundman of Hundman Publishing, publishers of Mainline Modeler and N-Scale, for being so supportive of our projects and encouraging us to make these articles available on-line.
This article will set out the steps taken to protect the Pocahontas Division from the worst of the beating it would otherwise get from climate factors. While this article is not specifically a model railroading article, our need for temperature and humidity control in our basements is so much more severe than most people's that this depth of advice on the subject can't be found anywhere else. I hope my hard-earned experiences of the last several years will be able to save you from serious damage to your layout with a few simple steps.
My basement does not have floor drains, as we are on a septic system, but our previous house did. If you have floor drains in your basement which flood, or even may flood, due to the sewer backing up, have a standpipe installed and leave it in place. A standpipe will stick up from the drain for a few feet, and allow water to rise that high in the sewer before it will spill over into your basement. Ask the person in your area who has lived there the longest what the historical high point of the sewers backing up has been, and then give yourself another six inches. Six inches of floodwater beyond the historical high point is an awful lot of water. If you need to drain water from your floor, say due to a water heater leak, remove the standpipe to drain the water and then replace the standpipe immediately. It goes without saying that the sewers will only back up when you are at work, on vacation, asleep, or otherwise unavailable or unawares.
If you have a sump, get a good high-capacity sump pump. Check the sump pump for proper operation regularly, during wet season storms when it is running. Make sure to install a check valve, so that if the outlet pipe becomes submerged outside the house, you don't siphon the entire outdoors back into your basement. Replace the check valve every couple of years, as the gasket and hinge are rubber and they rot or become brittle. Run the sump pump outlet pipe well away from the house. Some cities allow you to connect into the storm sewers at the curb if you are near one, and this is a good idea if you can. Don't exhaust the sump near the house; the water will run down the outside of the foundation and back into the sump.
You should also install a battery-operated secondary pump system. One month after I installed a new high-capacity sump pump to replace the one which failed and put several inches of water in my basement, the power went out during a major storm and I got several inches of water in my basement. Make sure to mount the secondary system so it is above the water level at which the main pump will kick in. This will make sure it isn't sitting in water rusting away, and then isn't ready when you need it. Check this secondary pump regularly by unplugging the main pump for several minutes during a big wet season storm to make sure the secondary pump kicks in and runs properly.
The secondary pump needs to be on its own outlet pipe, with its own check valve. Don't 'Y' them inside the basement, even if you do it above the check valves. The check valves will gurgle and let water run down through your secondary pump every time your main pump shuts off. This will rust out the secondary pump innards, and it won't be there when you need it. This was a hard lesson.
To keep the water from getting to the sump in the first place, run your gutter down spouts well out from the house. Black plastic ribbed tube in a 4" diameter size can be buried in the lawn to run out to a low spot in the yard away from the house. An adapter from gutter down spout to black plastic ribbed tube and the tube itself is available at any hardware store. Put screens over the gutters if you have mature trees which can drop leaves onto your roof, and fix any leaks in the gutters.
Most important, make sure the lawn around your house is sloped away from the house to keep runoff running off, and not collecting up against the foundation. A friend with a dump truck helps here; the Pocahontas Division took nine cubic yards of soil to reestablish the proper runoff slope from the house. Install clip-on plastic rain covers on any basement window wells; these window wells have drains in the bottom that run into your sump.
Finally, check your plumbing for leaks and weak spots, such as pipes hanging under their own weight or corrosion on the outside of pipes. Make sure no pipes are routed through uninsulated dead spots against outside walls where they might freeze. Replace and repair problem areas, use wire or pipe clamps to hang pipes properly, and reroute pipes out of potential freeze areas. Also, shut off the main water entry into your house, or turn off the well pump if you are on a well, whenever you go out of town on an extended trip. If a pipe breaks while you are gone, you won't fill up your basement with water you paid extra to put there.
To control humidity seeping into the room through the concrete basement walls, seal the walls with a good masonry sealing paint. Pay extra for a premium brand, and paint the walls twice. On the Pocahontas Division, we also had the railroad room framed in and drywalled. If you do this, insulate the room with an insulation that has a vapor barrier, or cover the concrete walls with plastic sheet before the framing is done. Once the framing and drywall is done, seal the drywall to the floor with a premium silicone caulk before you install any baseboard.
To control humidity seeping into the room through the floor, seal the floor with a good porch and floor enamel, following the directions on the paint can about priming for masonry surfaces. Paint the floor at the same time you paint the concrete walls, before you frame and drywall the room. Paint the floor even if you intend to carpet the railroad room later.
Much of the seeping through walls and floor will be controlled by the steps taken to keep the water away from the foundation and out of the sump, but sealing with good paint is still required, especially during the Midwest's spring and fall rainy seasons.
To control humidity from the sump, construct a sump cover from a sheet of 1/4" plywood. Make a template from paper first so you get a good fit around the pipes and wires which come from the pumps.
To control humidity from the floor drains, install a drain cover which has only a few holes in it. You should do this on top of the standpipe if you have one. Cut larger holes for the drain hoses from your central air conditioning, furnace mounted humidifier, and water softeners. Run hoses from these units directly to the drains and through the holes in the drain covers. Do not let this water run across the floor; it makes a wonderful humidifier. If you have a standpipe installed, you can run these hoses horizontally over to the top of the standpipe as all of these sources are higher than your standpipe is likely to be.
To control humidity from your laundry facilities, make a plywood cover for your laundry tubs. Put a line of adhesive weather-strip foam around the bottom of the cover where it contacts the tub. This also makes a great laundry sorting and folding table. Make sure your dryer vent tube is clamped securely at both ends and that there are no air leaks in the tube.
Warm air flowing down the stairs from the rest of the house is an issue because warm air can hold more water. Once that air cools in the basement, the relative humidity will be much higher, and it is the relative humidity which determines how easily the air will give up the moisture to participate in chemical reactions such as corrosion. Install a door at the top of the stairs if you don't already have one, and keep this door closed. A door at the bottom of the stairs will not do the job; cool, damp, heavy air from within the whole house will collect at the bottom of the stairwell and be let into the basement every time the door is opened. Install a door closer if you have family members who can't remember to close it once they pass through.
While most crawl spaces are very dry, yours may not be, and it's hard to tell how much moisture it gives off during the rainy season. There may be water on the other side of the foundation at that end of the house. If you have a half basement/half crawl space foundation like I do, you need to take some steps to control humidity from the crawl space portion. First, get in there and seal the foundation with the masonry sealing paint you used on the basement walls. Second, install a curtain between the crawl space portion of the foundation and the basement portion. Select a plastic coated curtain that will not breathe. This curtain will also be an aesthetic improvement, especially if you use the crawl space to store layout construction materials as I do.
Install a dehumidifier in the railroad room under the benchwork so that it blows out into an aisle. These units are relatively inexpensive to buy, and are not very expensive to run if you have already taken the above steps to keep most of the moisture out of the basement. I have installed two dehumidifiers, one in the layout room, and one in the workshop/crew lounge/helix/storage yard area. Hook these up via garden hose to your sump or floor drain through a hole in the cover just as you did with the other water sources. Do not use them without the hose, even though they come with a catch bucket. The bucket needs regular constant draining to keep the unit operating, and even if you are good about such things, vacations and model railroad conventions will keep you from getting to it all the time. Besides, the half full bucket is itself a source of humidity.
You should also humidify the house during the winter. Heating air reduces the relative humidity, and too dry can be as bad as too humid. Furnace mounted central humidifiers are not very expensive, and pay for themselves in reduced heating bills, as more humid air in the winter is comfortable at a lower temperature.
The problem is that you don't need much of a temperature swing to wreak havoc with your trackwork. Straight track can buckle, curved track will push and pull on the curve and go out of gauge, turnouts can be pulled apart, and insulated gaps can become conducting. Expansion joints of 1/16" every 3 feet can help, but cause other problems. Electrical conductivity is bad, and so the joints need to be jumpered. The rails tend to creep, leaving 4 expansion joints with no gap, and one gap of 5/16". Finally, 1/16" expansion joints are 10" craters in N scale and are very visible in photos.
We took several steps to control temperature on the Pocahontas Division. The first step is to find and seal any drafts to the outside. Use adhesive weather-strip foam or a very fine line of caulk around the window frames. Don't caulk the windows in tight; remember that they are your escape route if you have a fire in the staircase! Look around for any places that the concrete foundation and the framed first floor walls don't seal tight; try looking on a winter day with a swirling buffeting wind outside. Pass your hand around the top of the foundation where it joins the framed walls and feel for colder air. Find these leaks and plug them with caulk, putty, steel wool soaked in epoxy glue, or expanded foam.
If you frame in the railroad room, insulate the walls. This makes it easier to change and hold the temperature in the railroad room. Insulation can be had with a vapor barrier that helps the humidity control as well. The insulation in the walls also cuts down on the noise level by absorbing sound instead of allowing it to echo off the concrete walls and back into the layout room. We also insulated the interior wall separating the layout room from the workshop/crew lounge/helix/storage yard area, to keep down the transmission of noise from one to the other. You don't want the carousing of off-duty crew to interfere with serious operation next door.
We put both warm air and return registers into the layout room. Use a damper type register grille that allows you to adjust the air flow on both the warm air and the return registers. This close to the furnace the pressure differences from the ducts to the room are large enough that a little opening does a lot. We are thinking about hooking up a thermostat in the layout room to control motorized dampers on these registers and control the temperature more closely, but it hasn't been necessary yet.
The registers in the layout room serve double duty. In the summer, the basement serves as a source of cool, although moist, air to the central air conditioning. In the winter, the basement serves as a source of moist, although cool, air to the furnace and central humidifier. This helps balance the temperature and humidity variation in the house as well as the basement.
If your basement temperature swings opposite the seasons, that is, the basement is colder in the summer and warmer in the winter, your furnace and ducts may be leaking too much air into your basement. Turn the thermostat fan control to constant ON and the heat/cool switch to OFF, and look for these leaks with a smoking cigarette. Run the cigarette around the furnace and the duct joints and watch for the smoke to be blown around. Seal furnace and duct leaks with duct tape.
Another possible cause of the basement swinging opposite the seasons is overheating and overcooling of the main portion of the house. If you keep the heat at 74 and the A/C at 76, your basement will swing opposite the seasons due to the furnace and A/C running so much. Try temperatures of 72 and 78, or 70 and 80, for your winter/summer settings, and the basement won't swing opposite the seasons so much.
If your trackwork goes near any duct work or around the furnace, or if you still have a counter-seasonal temperature swing, you may need to insulate the furnace and or the ducts. Don't do this with styrofoam sheets! When the ducts get hot, the plastic foam will give off all kinds of noxious and potentially hazardous chemicals. Use an insulation which is specifically sold for insulating hot air ducts.
If you have a setback thermostat on your furnace and air conditioning, don't use the setback features. Digital setback thermostats are great in that they have superbly accurate temperature control, but using the setback feature is asking for trouble. The basement will not cool down much during the day when the furnace is set back, but when the furnace runs for twenty or thirty minutes continuously to bring the rest of the house back up to temperature, the basement temperature can rise dramatically. I have watched curved track move during this period, and watched expansion joints close!
Finally, do not set back your thermostat when going on vacation. The relatively minor amount you can save on your heating or air conditioning bills while you are gone is no consolation for the damage which can result to the railroad. The watchword through all of this is to keep temperature and humidity stable by avoiding changes in the way you heat and cool the house.
Additionally, have the ducts in your house cleaned out every five years or so. The air velocity in furnace ducts is not fast enough to keep dirt and dust from settling in the ducts. This dirt and dust occasionally dislodges and contributes to the flying airborne debris that eventually settles on the railroad. Duct cleaning services can reasonably clean this gunk out of your forced air system.
Not that I would ever sell this house. If someone wants to buy this house, he'll just have to take it with him and leave the basement and the Pocahontas Division where they are!
Next time I'll get back to model railroading proper. Promise!