from a combustible viewpoint what kind of flooring can a gas water heater sit on

I have a GSW gas water heater (model GG40S38ES-02). I think it's referred to as a direct vent model (i.e. it has vent ducting that goes into a chimney and so heat is vented up through the roof).

It has a label that gives me the following info.
+-------------------------------------+
| Minimum clearance to combustibles |
| |
| Top Front Flue Back Sides |
| 8" 4" 6" 1" 1" |
+-------------------------------------+

And then immediately under this section of clearances it say

"Floor - Plancher (I'm in Canada. Plancher is just the French word for Floor).
Combustible"

I'm installaing some laminate flooring in the area where the water heater is currently sitting in the basement on the unfinished concrete. I'm just trying to decide how close I can go to the water heater with the laminate flooring. I understand the "minimum clearance" dimensions section from a fire hazard viewpoint, but those dimensions don't really say anything about the actual floor that the water heater can sit on. What's confusing me the the "Floor Combustible" wording.

Is "Floor Combustible" simply trying to tell me (in a strange way) that the water heater could actually be sitting on a "combustible" material ... i.e. that effectively the base is effectively a "0 clearance" type surface from a fire hazard viewpoint?

I'd like to run the laminate flooring roughly in a circle around the water heater but I want to be safe in terms of how close I can come to the tank itself ... could I go to 0" (i.e. tight to the foot print that the tank makes on the floor); 1" away; 2" away etc. (Note that the tank itself will continue to sit on the normal feet it has that are sitting on the unfinished concrete ... no laminate actually under it).

Thanks for any thoughts.

I looked at the GSW website and read part of the installation instructions of a direct vent WH. It says it can be installed on a carpet, if you install it on a panel. I'd think that it might be prudent to put a drain pan underneath, and then you could run the laminate underneath (course, you'd have to drain and lift the thing first). I don't think you'd have a problem running the laminate right up to it. Best to just confirm with their tech support line for homeowners 1-888-GSW-TECH (479-8324). It's free, and then you'd know for sure. Since the heat rises, and the flue can get quite hot, it's important to have clearance aboveand to the sides for maintenance. Not so much beneath.

The biggest thing for the base is to ensure it is stable as you'd not want to have the thing tip. And, because most laminate doesn't like water at all, a pan underneath is a good idea. If you don't run the outlet to a real drain, it still has some advantages, since often (but by no means always), a leak starts out slow and small. If you notice water in the pan, you can fix it before it become an issue. It can progress from small to huge in a short time, but usually, you've got some time to react.

jadnashua said:

I looked at the GSW website and read part of the installation instructions of a direct vent WH. It says it can be installed on a carpet, if you install it on a panel. I'd think that it might be prudent to put a drain pan underneath, and then you could run the laminate underneath (course, you'd have to drain and lift the thing first). I don't think you'd have a problem running the laminate right up to it. Best to just confirm with their tech support line for homeowners 1-888-GSW-TECH (479-8324). It's free, and then you'd know for sure. Since the heat rises, and the flue can get quite hot, it's important to have clearance aboveand to the sides for maintenance. Not so much beneath.

The biggest thing for the base is to ensure it is stable as you'd not want to have the thing tip. And, because most laminate doesn't like water at all, a pan underneath is a good idea. If you don't run the outlet to a real drain, it still has some advantages, since often (but by no means always), a leak starts out slow and small. If you notice water in the pan, you can fix it before it become an issue. It can progress from small to huge in a short time, but usually, you've got some time to react.

Click to expand...

Thanks for your reply Jim. I ended up sending GSW a "Contact us" type email after I saw your response that confirmed my own thoughts. GSW's email response this afternoon, confirmed your thoughts exactly. The tank base can actually be sitting directly on a combustible surface (e.g. carpet or wood etc.). The "Floor combustible" wording on their label, just strikes me as being a little odd (IMHO), but what they heck.

The tank was just recently installed at my son's house, so I'm not going to the extent of retrofitting a drain pan, but it's certainly a good idea that I'll remember for the next time I'm involved in getting a new tank installed.