I have built a two story 30' x 40' stick framed shop. The main floor is separated into two sections, one which I plan to insulate, houses my machine tools, the other I use for welding, car repair etc. Niether area is panelled yet and I tying to decide how I should go about it. My current idea for the welding area is to cover the lower 48" with cement board ($30 for a 4 X 8 sheet) and the remainder with Aspenite covered in flame retardent paint ($11 for a 4 x 8 sheet). I do not want to use drywall because I do not want to tape it and it will get all bashed up. Does anyone have an opinion on the flame retardent paint?
So called "intumescent paints" protect fairly well, but not for protracted exposure. They have a 'bubbling' agent (usually sodium silicate/metasilicate) that forms a bubbly foam layer on the surface when heat is applied. Because the silicate bubbles are in large percentage glass, they protect by forming a layer of heat-resistant insulation when fire hits the painted object.
They aren't a silver bullet, but can greatly lengthen the exposure time before a wooden member becomes fully involved in the fire.
If the manufacturer doesn't list the coating as being of the intumescent variety, I wouldn't trust its ability to resist flame for very long.
Use 5/8" type X drywall and top it with FRP paneling. Don't bother to tape the drywall and offset the seams of the FRP from the drywall seams. All fire rated, durable and fully washable as well.
In my jurisdiction type X rock needs to be taped to meet code and presumably to keep the fire away from the studs. I would rock with at least one layer of 5/8" X D/W,fire tape the whole wall, finish tape from 4'AFF to the ceiling and run 1/4" tempered masonite along the wall sideways for impact protection. FRP or glass board would be nice but costs about $24.00 for a
4X8 sheet, ouch! There is another plastic type panel available, I think its vinyl, at about $8 a sheet. I'm going to investigate that to protect the walls in my bluing room.
Yes, the FRP is rather expensive. In one place I know of they did the 4' high guard section in a high abuse area with 1/8" AL diamond plate. Pretty darned expensive, but holds up well to palette jack abuse.
If you want true fireproofing, there's nothing better than good old gypsum drywall. Use 5/8" installed properly, with fire rated doors and closers and no unprotected penetrations, gets you a two hour rated firewall. Unless you are WAY out in the sticks, the Fire Department can get there before it spreads.
Rather than spend a lot of money on the cement board I'd drywall the entire room in plain 1/2", tape the joints - it doesn't have to be three coats all sanded down and pretty, but I would still mud over the screws and one coat over the joints, a fast sand to knock the high spots down, and now you are fireproof. Hit it with one heavy coat of PVA Drywall Primer/Sealer so any liquids that make it through don't soak in and stain or wreck the drywall.
And then for armor against abuse panel over the top of the drywall walls with 1/4" or better plywood or hardboard. Screw it to the studs like the drywall, finish the corners with simple pine molding, and coat with the fire retardant paint to keep little sparks from sticking. And if you manage to dent it, you change a sheet.
And if anyone ever decides to build a new bigger shop and turn the old shop into a guest house, it's mostly done. Just strip the plywood, patch the nail holes, and give the joints a second coat. Or fill the big divots and hit it with the spray texture gun, the spatter texture hides a lot of little sins.
Just a suggestion - check out used aluminum printing plates. Cheap! Covering a wall with this material may not meet code but I challenge anyone to try and set fire to a wall so covered from normal ambient hazards.
As others have said, use drywall. If you don't know how or don't want to tape, hire it done or use fire tape:
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You can install a layer of wafer board under the drywall. This will provide an abuse resistant wall which will allow you to fasten screws, cabinets, tool racks, etc anywhere you want. Cement board (Durock, Wonder Board) will not give you a very useable wall surface and would require taping or sealing to protect the studs in a fire. I'm not sure what aspenite is. I wouldn't spend the money on intumescent paint. How are you protecting the second floor? Fires go up long before they go sideways. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net
I used 4'x8' sheets of 24 ga. galvanized steel ordered from a local HVAC shop. I simply nailed the sheets onto the studs. The idea is to prevent sparks from welding coming in contact with flamable parts of the wood frame structure. Steel does the job.
Upon reflection I think you are right. I hate the idea of all the plaster dust around my machines, but I will just have to tarp everything up. Part of my problem is that I haven't gotten the framing or electrical inspections done yet. What I should really do is do the work required to pass the inspections first (get engineering drawings stamped for the gambrel roof framing, make the stairs to the top floor etc.)
It's the fire retardant fiberglass / composite paneling often seen in food service areas. You can find it at Home Depot / Lowe's along with the molded trim pieces that go with it. As noted, it's kind of expensive, but it's durable, washable and of course fire retardant.
Others have recommended drywall. I hate taping/sanding, so in my 2 story garage/shop I'm gonna do plaster. With a skim-coat system, the "lath" is basically drywall (with a blue paper that holds plaster better). You screw it onto the studs just like drywall and tape with a fiberglass-mesh, self-adhesive tape. I plan to apply the skim coat and then smooth it out moderately well, and paint it. No need to sand, and the wall will have a trowelled stucco look to it. A bonus to this method is that plaster is so much harder (and dent-resistant) than drywall with joint compound. Properly smoothed plaster is very hard work, though, 'cause you have to wait until the plaster is set stiff, then *lean* into it with the trowel to get that nice smooth finish. My method requires a lot less work, and very little skill, and the result should look good (at least that's the plan). I should be starting it in about a month.
I also plan to use cement board (Hardi Panel) for the bottom 4' in the garage bays, just to resist abuse.
As for fire resistance, you may notice that many (most?) fire-rated safes use regular gypsum board as the fireproofing material.
Try to limit the number of crevices and corners, dust accumulators are a bigger fire risk than just a flammable wood wall or floor. My welding table has a layer of 1/4" lauan under the grid to keep spatter off the stuff below, Never set it on fire in 7 years of daily use. Wood shavings or other flammable debris will burn much easier.
There are wired smoke detectors available that use a third 'carrier' wire to tie multiple units together. I'd put one in the shop and one in the house if the wiring were practical, thus if a fire starts where you aren't you'll find out faster than you otherwise might. Home depot sells these.
There are flame retardant additives for latex paint, we use the stuff all the time at work. One cup per gallon of paint meets NYC, L.A. and Chicago fire codes for places of assembly, which is probably a lot tougher than what you need. This is what we use.
Pete C might have it - but there are drywalls that are used as firewalls between shops (garages) and the house, and behind wood stoves...
It isn't cement wall - but it is a fire rated wall. Talk to the local lumber yard and see what they have.
Martin
Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member
I recently got accused of not being able to read, because I deliberately ignored part of a request, and gave my own answer.
But did everyone miss the question here? He didn't ask if we had suggestions about how to flame-proof his shop, he asked, "Does anyone have an opinion on the flame retardent paint?"
Does anyone have experience with it? I gave him a tech overview of the product, but I've only ever used it once.
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