We don't have a separate vent, but the dryer must be vented to the outside.
We have ours on a first floor and put the washer in a pan. We also put a waterbug in the pan that's hooked up to the alarm system. I suppose you could try to waterproof the whole floor, but that seems like a bit of overkill.

Our laundry room is on the second floor. We have a slightly sloping, slightly recessed floor with a drain under the washer/dryer area. That section of the floor (about a 6x3 area) is waterproofed. Basically, the floor under the washer/dryer area was done the same way one might do a roll-in shower. (i.e., the subfloor is dropped down from the surrounding subfloor and then waterproofed and tiled to bring it up almost level with the rest of the flooring again. (See the link below) The rest of our laundry floor is also tiled but it is not 'waterproofed'.

Do make certain that the drain under your washer/dryer shares a trap with either the washer drain line or with a nearby sink. Otherwise, because you won't be putting water down the drain EXCEPT in an emergency, the water in the trap will evaporate out over time and begin allowing septic gasses to enter your home thru the drain.

As Annie points out, your dryer will be vented to the outside of the house and your laundry room should have an HVAC vent. Other than those, we don't have any additional vents like one might have in a bathroom. Washers/dryers - even running constantly - simply don't produce the kinds of humidity in the room that a 10 or 15 minute hot shower will. And, of course, you don't have the same odors to deal with. Even if you often hang clothing up to drip dry (as I do), you shouldn't have any problems with excessive humidity in your laundry room if your washer and dryer are functioning properly so, I wouldn't bother with a 'fart-fan'.

Here is a link that might be useful: flooring under washer/dryer

Check with your local authority on both issues. Some municipalities require the drains and/or the vent fans. Even if it's not required, the drain is cheap insurance.

Pan under washing machine -- check.
Vent fan in laundry room -- check.

how often do washers leak? I have never nor has anyone I know had leak or flood.

gaonmymind - once you think it will never happen it will. We had the fill valve go bad on our washer. The fill valve as you would expect tells the washer when the water has reached the proper level, and shuts off. When it's bad it just keeps filling the washer and it spills over and doesn't stop until you turn off the machine. Our machine overflowed for hours before we noticed it. Luckily it was in the basement next to a floor drain. No damage except for a large water bill. But if it were on the main floor or second floor it would have been a nightmare.

We just moved and now have first floor laundry. I have a pan under the washer and will be ordering a water bug. But you have to be home to hear the alarm. If you're gone and the washer it spilling over you have no way to know. I'm consulting my BIL about connecting the hose on the pan to the drain on the slop sink. But I remember seeing the water spill over the sides, nothing could of helped our problem.

Thank you all for your feedback! I've been busy managing a sick kid all day, so just now getting back.

Bevangel, I was thinking something similar to what you describe, but I may need a "curb". We'll see. I just think I might prefer that to a pan. How does the slanted floor affect your balance on your washer? (or, do you balance it with the little twisty feet)?

If I can't do my floor the way I was thinking (like a shower pan), where did you all get your laundry pan?

And, yes, on making sure the drain connects to a shared trap with something that will regularly have water down it. :)

This laundry will be on the second floor, so YES! I am paranoid that something like what happened to vitiminj would happen to me and flood everything. Don't want that to happen.

It sounds like the vent must be a regional thing. I'll check with the local permit office (hoping I don't need one; fewer holes in the roof, the better in my opinion).

Again, thank you!

I never had one leak but I have had the rubber hoses at the supply lines crack and break and flood the room, luckily I was home and was able to shut off the main as it was a HOT water load. From now on steel mesh connections:)

We do not have a ceiling vent. Just the standard vent but it is metal (not plastic/wire spiral exhaust) make sure they screen it off with a removable screen if you can so you don't have uninvited house guests but you're still able to blow it clean for maintenance.

They require ceiling vents on timers here. The feeling I got is that most people think it's unnecessary. I can say that I don't use the vent for the w/d; I use it when the dogs smell like wet dogs and are in there. :)

Get the flood safe supply lines and use a water leak sensor. If you are home, the leak sensor will alert you. If you are otherwise occupied, like out working in the yard, the flood safe supply lines will shut off the water.

Personally, I would never run either the washer or dryer when I wasn't actually home. I've had both malfunction in one form or another, and because I was home, the only consequence was a larger utility bill rather than a home disaster. I've had friends that were not so lucky with a leak in a second floor washing machine and another friend with a house fire from a dryer. Preventive maintenance IS required. You don't just put the machines in place and don't touch them again for 10 years or until they break, whichever comes first. Pull those machines out when you set your clocks back or forward and clean behind them, checking the integrity and flexibility of the supply hoses, as well as cleaning out the dryer ducts all the way to the exit of the home. If you have rubber supply lines, replace them immediately if they are more than a couple of years old.

Kirkhall, the "slope" of the floor under my washer/dryer is very slight and the front and back edges where the machine legs sit are basically at the same level. The drain (and therefore the "low spot") is pretty much at the center so it doesn't really affect the legs. I had no problems leveling the machines perfectly using the screw feet that are on the machines when you buy them.

I looked again at my laundry room floor tho and actually we do have "curbs" at the back and on the left and right sides of the machines but not at the front. (The curbs are pretty much hidden by the walls and cabinetry so I'd forgotten about them.) But, I knew I wanted to be able to pull the machines out to clean behind them and a curb at the front would have forced me to lift them up to pull them forward. No way I could have managed that by myself. So that's why I insisted on no curb at the front.

Also, I suspect that leveling the machines might have been more difficult if we'd had a curb at the front because it would have been hard to get a tool into position to rotate the screw feet. DH has extra long socket-wrench kind of thing that will reach to the back feet from the front edge if we need to rotate one of the back feet to get things level. But, if there were a curb all the way around, we wouldn't be able to get the tool under the washer.

Ditto to everything posted about the necessity for MAINTENANCE to assure that supply lines don't burst. Always a good idea to check those fairly regularly to make sure they're still good because a broken water supply line can spray water all around your laundry room.

Excellent! Thank you all!
One of the reasons I am so looking forward to this remodel (there are a lot of reasons, of course, but...) is that I will be able to more easily do maintenance. Right now, my W/D sit in a closet that we had to modify to get them in! And, they have not been moved since we put them in (about 6 yrs ago.) I did replace the hoses just recently on the washer. :)

But, there is no easy way to get the 4 1/2 feet of machinery out the 4 foot bifold entry doors to their closet. Getting them out of where they are will be a huge improvement in terms of annual maintenance.

When we built my parents house last year, they put drains in under the washing machine and water heater. They are both close to each other, so they share the same trap. Every month when my mother changes out the HVAC filter, she adds a cup of water to one of the drains. The one under the water heater is very easy to get to.

I agree that you should use steel mesh hoses and don't run the washer or dryer when no one is home. My wife is paranoid about leaks so she shuts off the hot and cold supply lines after she's done with the weekly batch of laundry. The shut off valves are high enough on the wall that they are easily accessible above our front loader and they are the 1/4 turn variety so it's very quick and easy.

A friend of ours was away on vacation when the washer hose let go...they were on city water so it ended up flooding the entire first floor of their house and all the flooring had to be replaced.

Our hook up has a valve shut off lever that we turn off after every use of the machine....it automatically shuts off both supply lines. Apparently it's quite std these days.