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Fireproofing OSB walls and floors

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Littlebriar

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I have a room that has OSB on walls and ceiling and floor. The room is 16' x 14'. I plan to convert this room into my metal fab area. I will be welding in this area and am concerned about burning the place down with smoldering embers. I had a friend lose his garage to a stray spark. I'm looking for some ideas on fireproofing this area. I'm thinking of metal barn siding for the walls and ceiling and maybe hardy or cement board for the floors. I'm concerned that the cement board will be hard to sweep and that the metal barn siding will make it difficult to hang stuff on the walls. I'm also considering just hanging welding curtain in one of the corners and using the backer board just in a quarter of the shop.
Other ideas would be appreciated.
 

Eddyde

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Standard drywall (sheetrock) will be fine for the walls and ceiling. I wouldn't put down bare Hardy or any cement board, unless they are covered with ceramic tile, they won't hold up. Commercial vinyl tile may be a good choice but you should install hard board (masonite) glued down, first as they won't hold up well if installed directly on OSB.
A shop I worked at years ago had a wood plank floor, they had installed a couple of sheets of galvanized sheet metal under the welding bench.
 
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mickri

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X2 on the drywall for the walls and ceiling. As for the floor need more info about the building and exactly what you plan to fabricate. My first thought was lightweight concrete like what is used on the second floor in some homes. It is still pretty heavy so there might be some structural issues to deal with. Concrete pavers are another option. Ceramic tile will probably crack and break if heavy objects are dropped on it. Expensive too. I think that a metal floor would be slippery.
 

pontiac428

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This is where welding curtains/screens and fire blankets can help contain sparks and ballies during hot work. They're cheap and durable. I understand your concern, once OSB starts burning it's bad news.
 

cathead

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A solution of boric acid in water painted on to OSB will help to prevent smouldering type of fires caused by welding. It is also
really good used on the cloth covering on boilers to prevent fires. As an added bonus, boric acid is quite deadly to ants and
termites and other similar critters. The metal coverings in the above posts is obviously a better fire preventative but boric acid
applied to exposed wood can make it a lot less combustible.
 

Latinrascalrg1

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This suggestion may be a bit unorthodox but Hardiebacker tile underlayment "cement board" is relatively inexpensive and easy to work with and is very durable, fireproof and it can be primed and painted which also helps with keeping things clean and tidy and it may even help contain workshop noise to the workshop! It comes in 3 different thicknesses I believe but id use the 1/4" thick sheets for an application such as this.
 
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jwmay

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I’d go for Sheetrock for the walls. If it’s sturdy enough, the concrete pavers seem like a good low cost and fast way to get the area ready to work in.
 

Littlebriar

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Thanks for the good ideas. Sheet rock looks like the way to go but I don't really want to use it if I can avoid it. I hate hanging the stuff, and I hate mudding it even more. Wonder if anyone has used FiberGlass Reinforced panels? This one from Lowes has a Class A fire rating. Would look good, be easy to clean and could just be glued on. I would need about 10 sheets for the job.
 

Latinrascalrg1

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Fyi Class A "Combustible" rating doesn't mean it is fireproof, only that it is slow to spread fire through its own combustion. I was thinking you wanted Non-Combustabile options since you stated you were worried about Fire bringing the place down!
 

whitmore

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I have a room that has OSB on walls and ceiling and floor. ...I will be welding in this area and am concerned about burning the place down
Such concern indicates... good mental health.

There are ire-retardant paints that instead of burning kind of 'puff up' when hot (and this insulates the wood behind them).
OSB is very thirsty, you'll want to spray on some primer first (the 'contains shellac' kind dries in an hour or three) and then
follow up with a suitable fire-retardant paint. Any good paint store will have some options.

Both brush and roller are annoyingly ineffective on OSB; you really need a sprayer, and priming first is key to keeping paint
usage modest.

That's good for walls, but for a ceiling I'd go with sheetrock (could be thin stuff); it's relatively easy to apply with glue/screws
and a helper or two with T-shaped sticks can hold the panels up while you apply the screwgun. Tape/mud on the seams
is always an option, but few folk will notice ceiling appearance.

As for the floor... no idea. You might not want to seal it (depends on moisture from below) and paint won't hold up.
If you don't have concrete, or dirt, it won't take hot falling objects gracefully. I'd be tempted to use lots of
cheap ceramic tiles, and just let 'em break from time to time... that's gonna be time-consuming, though.
 

Herk

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5/8" drywall has a 20 minute fire rating, one of the reasons it is fire code for ceilings. I would refer to the fire code for an attached garage space which must also have a 20 minute rating. Overlaying OSB should be fairly straightforward. Thinner drywall (1/4 or 3/8) costs more and is no easier to install aside from being lighter. Likes to break.
 

Littlebriar

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More good suggestions. I had no idea about the fire retardant paint. Further research indicates it meets 30 minute protection which is Class A. I now understand that's not fireproof as Latinrascalrg1 pointed out but that might meet my needs. Welding isn't going to be a daily thing and I might hang some welding blanket on the walls in the corner where the welding table will be. Application will be easy because I have access to a good airless sprayer. I think I'll install some thin gauge barn siding on the ceiling instead of drywall. It will look good and will be totally fireproof. Maybe a bit noisy though.
Still trying to figure out the floor. Hardy board under some cheap tile may be the way to go. I've laid quite a bit of tile in the past so the project doesn't bother me. If it cracks, no big deal. It's a shop.
 

Aaron_W

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What is the floor currently?


Upgrading the building materials is great but don't overlook detection / suppression, and general house keeping. Install a smoke detector, have working fire extinguishers, consider a small fire sprinkler system in that area.
Make sure flammables / combustibles are properly stored away from heat generating activities like welding. Don't overlook sealing up nooks and crannys that could conceal hot sparks and slag. Seal the joints along the floor, make sure what ever wall covering you choose is sealed between panels.

It isn't that easy to ignite OSB, but a can full of rags or oily swarf can certainly help get it going. All the fire proofing in the world won't help if flammable contents are available to a heat source.

If you do something with a higher than normal risk of fire, plan standing a fire watch into your routine. Including an activity that will keep you into the shop for 15-60 minutes after high risk activities will greatly reduce the odds of a hidden fire developing into a major fire, because you will be there to stop it while small.


They make smart smoke detectors that will activate an alarm on your cell phone, to alert you when you are beyond the hearing range of a standard smoke detector.
 

Littlebriar

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What is the floor currently?
The floor is OSB right now.
Good suggestion on the smart smoke detector. I had a friend who burnt his shop down because of an ember he didn't see when he left for the day.
 

Aaron_W

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Not really sure about the floor. Personally I like concrete or brick around fire, but don't think you could pour it thick enough to be durable in a whole room without weight becoming an issue. Maybe check with fire place / wood stove suppliers, wood embers are not as hot but they must run across similar concerns.


Embers can hide for a surprisingly long time if protected. I had a co-worker who had a major shop fire about 15 years ago. He was doing everything right, full fire alarm system, sprinkler over the "hot work" part of his shop and in general a pretty neat and tidy kind of guy. A spark from welding got out of his shop area into some stuff he was temporarily storing and it waited until the middle of the night to get going. He had an alarm system that notified the fire department and woke him up, so he didn't lose the building but damage was still significant.
 
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