Welding backer inside house

[BMan2005]

I’m going to be welding up 1/4” plate in the room of our house. House is under construction and bare cement floors. My question is, what is the best thing to use against the walls between the 1/4” plate and wood stud walls for one prevention of fire welding on the plate against the studs, two fire insulation from outside the room.

I was thinking blanket rock wool sheets, then I read it’s advised to keep away from direct heat. Same for Sheetrock that I know a lot of retail store safes use.
My last idea is sone type of cement board? I could fasten it to the walls and ceiling and lay the plate to it and weld up. Ideas?

 

[Rustyiron]

Is this for a regular welding area?
Are welding sparks your only concern?
18ga sheet metal is enough protection from welding sparks.
I'd kinda be concerned about trying to cover wood framing to the point where you can't visibly check for something smoldering or douse it with water. I'd come down the wall with sheet metal with a 90* bend at the bottom that turned into the room 1-2" then just lay your 1/4" sheet over it at the floor/wall.
Overall, it would take a crazy amount of welding or grinding sparks to set the framing on fire.
Maybe I'm not understanding what you are doing.

 

[Topzide]

I would use drywall with a cement board on top of it. Just like a safe with the steel, then drywall inside. JM2C.

 

[BMan2005]

Is this for a regular welding area?
Are welding sparks your only concern?
18ga sheet metal is enough protection from welding sparks.
I'd kinda be concerned about trying to cover wood framing to the point where you can't visibly check for something smoldering or douse it with water. I'd come down the wall with sheet metal with a 90* bend at the bottom that turned into the room 1-2" then just lay your 1/4" sheet over it at the floor/wall.
Overall, it would take a crazy amount of welding or grinding sparks to set the framing on fire.
Maybe I'm not understanding what you are doing.

No this is for a gun room/vault. It will be 1/4 plate but to weld it I need something fire proof between the steel and wood stud walls

 

[BMan2005]

I would use drywall with a cement board on top of it. Just like a safe with the steel, then drywall inside. JM2C.

You think drywall then Cement board wound be best? Or two layers of cement board instead?

 

[Hay Dude]

I used cement board when I had to weld a beam across lally column poles and had a fireman stand by with garden hose

 

[Topzide]

Cement board is providing the fire and heat protection from the welding. The drywall will act as a fire buffer if you house caught fire. Have you tried to burn drywall? The paper goes up, but the drywall just glows. We used to build townhouses that had two 1" drywall layers between units!

 

[BMan2005]

Cement board is providing the fire and heat protection from the welding. The drywall will act as a fire buffer if you house caught fire. Have you tried to burn drywall? The paper goes up, but the drywall just glows. We used to build townhouses that had two 1" drywall layers between units!

Sounds like a plan. I’ll get a material list tomorrow. Thank you!

 

[BlueKnife]

Any reason you can't do the welding first and then frame around it? Are you building a steel box, of sorts?

 

[etpm]

If you really need to weld this safe in place then get some Hardi backer board, wet the studs, put the Hardi backer board in place, wet it, then start welding away. You will have no problems with charred studs.
Eric