Non combustible wall in wood frame house

[jyl]

Suppose you want to change a conventional 2x4 wood stud and lath/plaster wall to a non-combustible wall. For example, to install a commercial kitchen in a house.

Would you

1. Remove lath/plaster, remove wood stud, replace with metal stud, repeat until wall is all metal stud, then cement board? Seems you’d have to install the upper and lower channel in sections? Suppose it is a exterior wall with exterior sheathing nailed to the studs?

2. Build a second wall of metal channel and studs, inboard of the original wall with a 1” air gap, then cement board? Impossible to cement board the side facing the original wall. Might take a fraction of the time/effort of #1.

[masraum]

How non-combustible does it need to be? Is the house being turned into a restaurant where it's got to meet some code, or is the kitchen just being upgraded to a commercial style in a residence?

[unclebilly]

Does the wall have to be structural?

Why not just put a layer of stainless on the kitchen side?

[dad911]

Who/why is requiring non-combustible?

Manufacturer of appliance, building codes, or your home-owners insurance?

Doesn't the stove come with the stainless wall behind it?

With a commercial hood, you may need make-up air.

[jyl]

Commercial kitchen, needs to meet applicable code. House to be converted to restaurant.

Cooking equipment will be on one 5 foot wall, the red rectangle at top of image below. It is a smallish bumpout under a flat roof there. Flat roof -> easy ducting for hood/MUA. Would be nice to not sacrifice inches but could be done.

[jyl]

If build second wall, was thinking could be like this

[A930Rocket]

if you need a one hour rated wall, you can’t guess what will work. Look for a U L Listed 1 hour rated wall system, as there are several to choose from. FYI, whichever one you pick, you must use the materials used, because that’s the way the system was tested. No substitutions are allowed.

[jyl]

Ah so, like https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies.html then.

Looks like metal studs w/ two layers fire-resistant gypsum on each side gives 2 hour rating.

[A930Rocket]

Do you need one hour, two hour or non-combustible?

From the USG website, but there are many gypsum websites with firewall assemblies

https://www.usg.com/content/usgcom/en/design-studio/wall-assemblies.html

[A930Rocket]

You can use wood or steel. Wood will give you a 8 inch thick min wall and steel will give you a 6.625 thick min wall for a 1 hour rating.

Is this a load bearing wall? You’ll need to keep that in mind.

[jyl]

The 5' wall behind the cooking line, that I need to be non-combustible, is not load bearing.

The short wall to the side (at very top of diagram) is exterior wall thus load bearing, but I may not need that to be non-combustible.

[dad911]

Originally Posted by jyl

Commercial kitchen, needs to meet applicable code. House to be converted to restaurant.

.....

I'm going to assume IBC, you are going to have to check your jurisdiction as to which version. Requirements should be spelled out in there.

Don't you also need a fire suppression system in the range hood?

[jyl]

Originally Posted by dad911

I'm going to assume IBC, you are going to have to check your jurisdiction as to which version. Requirements should be spelled out in there.

Don't you also need a fire suppression system in the range hood?

Yes, fire suppression in hood, fire sprinklers throughout.

[A930Rocket]

You may need to talk to your building department or Fire Dept about the non-combustion requirement and clarify. The USG site has a 4 hour wall. Non-combustible would have to be steel, concrete or masonry I would think.

[Zeke]

Originally Posted by A930Rocket

You may need to talk to your building department or Fire Dept about the non-combustion requirement and clarify. The USG site has a 4 hour wall. Non-combustible would have to be steel, concrete or masonry I would think.

Right. Even though you and a few others here are contractors, this is not the place to ask.

FWIW, 3M makes a foil type product and there are cement boards rated for fireplace construction. Apparently one can still obtain products like Transite and it can be fabricated in a closed environment using a wet cutting process like water jetting.

Good luck finding more info on that, but I had some that I found awhile back and used it behind stainless steel over plaster to surround my vintage Wolf range. I just scored it, misted it and snapped the cut.

No inspectors were involved. It was much easier to build and remodel in my days as a contractor and I did a few commercial kitchens. Tough work meeting codes for building and health codes even then (40 years ago). I wouldn't step foot in that today.

[jyl]

I’ll be consulting with a commercial kitchen place, and my architect. But want to be educated, and if any work can be DIYed I want to.

[look 171]

Sounds like this is your home, John? Commercial kitchen in a home? To get that up to code and Im sure you aren't the first one who's done this, my biggest concern is insurance? Will it be insurance as a commercial kitchen, if not, a typical home owner insurance? What is a fire occurs? I am sure they will wiggle out as much as they can. Something to look into.

I built out two restaurants. They were high end one and it was a pain in my arse only because I was not use to building them and didn't know the specific codes even though they were in the plans.

[jyl]

Originally Posted by look 171

Sounds like this is your home, John? Commercial kitchen in a home? To get that up to code and Im sure you aren't the first one who's done this, my biggest concern is insurance? Will it be insurance as a commercial kitchen, if not, a typical home owner insurance? What is a fire occurs? I am sure they will wiggle out as much as they can. Something to look into.

I built out two restaurants. They were high end one and it was a pain in my arse only because I was not use to building them and didn't know the specific codes even though they were in the plans.

This is a former house, old wood (1908 four square), now triplex but zoned commercial, I may be buying to convert to commercial. My architect has gone through it, he thinks main costs will be 1) fire sprinklers, 2) commercial kitchen, 3) permits & related fees. So I’m trying to get educated on 1) and 2).

On 3), Portland sux. I used the city’s online estimator which appears super detailed and gives a line-by-line itemized estimate of total fees and charges. WTF $80,000!? So I spent an hour reading the city code and found that my project should be exempt from over half of that. Call architect, yup, total fees should be more like $30K. So, I ask, why did the online estimator say $80K? Well, these are exemptions, the property owner has to learn about them and affirmatively apply for them, they aren’t automatic, and the city doesn’t go out of its way to tell you about them.

So I’m trying to educate myself about everything else, just in case there’s other things like that.

And it’ll be insured etc as a commercial building, I have a quote for that already and sprinkler should help.

[look 171]

John, sounds like a plan and you should be good. When is the Pelican party for a great meal. I know you are a foodie.

[jyl]

Ugh - hit a snag - deal is for seller to evict the three tenants on his own dime (90 days notice and pays them $3-4K each) and escrow closes when property is vacant. Turns out under local law it is more complicated. They’ve been there over a year so they can only be evicted for certain reasons and selling the building is not one of them. Converting to commercial is a qualifying reason. But seller isn’t the one who will convert it. It’s me, and I don’t want to deal with evicting them (or paying for it). Not sure how this will get solved. Maybe we cut the price.