[The5thofNov.]

Hello everyone. I have a remodel that I am working on and need some help. The building is about 100 years old, a commercial building. It is 2 stories with an attic. The first level is currently rented as a store. The 2nd level is the one I am renovating and will be taken down to studs and joists. I want to use a subfloor sheeting that is fire rated so I can provide the necessary requirements to rent the upstairs as a residential. Does anyone know a good subfloor material that is commonly available that would meet this need? I talked to the building inspector and he said I needed a 1 hour fire resistance rating between the levels to allow a commercial rental downstairs and a residential upstairs. This is commonly done with drywall on the ceiling below but I will not be working down there. The area to be covered is about 1000 square feet. Thanks!

 

[WhatRnsdownhill]

why dont you ask the building inspector what he recommends since he will be inspecting it.. other than tile with a mud job, but your not going to get where any walls are framed, so you wont have a solid fire resistant floor,do the wall cavities also need to be fire rated?

 

[The5thofNov.]

I will be removing the interior walls to put new subfloor under them as well. the exterior framed walls will stay where they are of course.

 

[Mingledtrash]

You are opening up a huge can of worms with this one. its not something where you can just throw down some fire rated sheathing and be done with it.

I am sorry to tell you that the fire proofing must be done on the down stairs ceiling.

The inspector may not be familiar with this situation because you most definitely need at least 2 hour rated fire-partition and it must separate the two occupancy classes completely meaning it has to go through the entire floor and through the exterior walls. Any electrical, plumbing and venting that goes through this space will need to be fire rated.

all supporting structures for the floor must be protected as well. Meaning any support posts, beams, and bearing walls must be fireproofed as well.

It very well may be cheaper and easier to install a fire sprinkler system in this situation than it is to retroactively install a fire partition.

The best thing you can do is hire a professional architect and engineer that has experience in commercial and draw up a proposal to retrofit your building.

Another thing i just thought of... if you dont have drawings and specs. of the retro will you even be able to insure it?

 

[oh'mike]

You deffinately need proffessional design help---the fire proofing is typically below the floor joists----to keep them from burning and dropping the second floor deck into the store below---

I don't think a fire rated floor covering is going to pass the fire inspection.

 

[The5thofNov.]

I appreciate the responses. The building is currently insured and I do not foresee any problem with keeping that insurance. I will not be hiring anyone to do any drawings or anything, too expensive. The inspector already told me he thought a fire rated subfloor would work as long as I could find one, so I was just looking for suggestions on known fire rated subfloor material. Sounds like I should just ask the inspector what he wants and give it to him, then I get my inspection and move on.

 

[Anti-wingnut]

Fire rated plowood does not a fire rated assembly make.

Good luck with your project. Not really sure why you asked here, you already knew what you were going to do, and what the "inspector" told you. When people disagree with that assessment, you tell again tell us exactly what you are planning and how you can't afford any design work. Seems like you came here merely for a blessing.

Fire rated plywood does nothing to protect your building from the most likely danger, fire from below consuming the dry ancient floor joists. Your building may be grandfathered, the inspector may be in error or you may live in a loose municipality. It all depends on the prior use of the building. Are these apartments new in a former office building? That normally involves more stringent fire assemblies than just some FR plywood.

But anyway, good luck and tell us how it turns out.

 

[The5thofNov.]

I asked here because I thought someone may know of a fire rated sub floor material. I am not looking for a blessing, I am not even sure what you mean by that. I have built several houses but have no experience on an old renovation like this. The prior use of the building was commercial downstairs and it did have an apartment upstairs at one time but that was probably 30 years ago. It has been used for storage since the apartment was vacated. The remnant of a kitchen and bathroom are still there. The building is 100 years old, the downstairs level is made entirely of wood, including the walls. The fact is that a fire rated floor between the levels is really pointless because 100 year old seasoned pine walls will burn pretty quickly I imagine. I have to do what is necessary to pass an inspection, if that means putting down a fire rated sub floor upstairs then that is what I will do. I probably should have been a little clearer in my initial post but I already know what a real fire rated floor should look like, the composition is easily found on the internet. My experience with inspectors is that you do what they ask or you don't pass inspection, regardless if they are right or not.

 

[The5thofNov.]

Honestly, I believe mingled suggestion of a sprinkler system downstairs makes the most sense if one were really looking to protect the structure.

 

[Anti-wingnut]

Honestly, I believe mingled suggestion of a sprinkler system downstairs makes the most sense if one were really looking to protect the structure.

A set of plans makes the most sense.

A commercial/MF building is going to require a full fire sprinkler system, not the PEX systems tied into domestic plumbing like you see in SFRs. You could spend into the tens of thousands on the building alone to bring in a sprinkler system.

 

[The5thofNov.]

Anti,
You do not know what the code is where I am located. A set of plans is overkill for this project. I am not in a city or somewhere north of the mason-dixon line. We use common sense and do not spend money where it is not needed. A sprinkler system on a 1000 square foot building is not going to cost $10,000+. You are taking this in a direction I never intended. I asked a simple question about fire rated sub flooring material. A set of plans is not going to protect the structure from fire and/or pass the inspection. I am not spending the money on plans, I am not paying an engineer or architect. Is this not called the Do it yourself chatroom? Am I missing something? I believe I may have looked in the wrong location for assistance or you should change the name to "hire a professional" chatroom. Seriously, does anyone know of a fire rated sub floor material?

 

[Anti-wingnut]

How do you know how much a fire sprinkler system would cost?

You asked a question in the home improvement section, but are clearly asking about a commercial building.

How can the building be 1000 square feet? You said that the building is two stories, and the apartment is 1000 square feet. Isn't 1000+1000>1000?

 

[Anti-wingnut]

Anti,
A set of plans is overkill for this project. I am not in a city or somewhere north of the mason-dixon line. We use common sense and do not spend money where it is not needed.

Then how do you know that FR plywood is even needed? If the building is as you say, then the FR floor is something just being pulled from thin air by the inspector. Seems like an uneccesary cost unless the inspector can prove it is required by code.

What does common sense say about that?

 

[The5thofNov.]

I know how much it could cost because I looked it up how much a sprinkler system can cost. I asked in the home improvement section because I am dealing with a small structure and I am renovating a residential space. The reason I even came here is because it is supposed to be a "do it yourself" forum. The building itself is 2000 square feet, 1000 per floor. If you read my post regarding Mingled's suggestion I said a sprinkler system downstairs, meaning 1000 square feet. Sprinklers for upstairs would be cheaper since it would be residential if they need to be installed in the entire building, if the inspector so desires. Mingled response was not and answer to my question but at least was helpful. I will be working on the cost of installing sprinklers because it would be a solution to the problem and maybe the best one. Anti, do you have a suggestion for a fire rated sub floor material? If not then please do not respond. I did not come on a "do it yourself" forum for your free professional opinion on how I should handle my renovation. I asked a specific question about a building material. I expected advice from others who "do it themselves" and may know of such a material as a fire rated sub floor. Thanks

 

[The5thofNov.]

Then how do you know that FR plywood is even needed? If the building is as you say, then the FR floor is something just being pulled from thin air by the inspector. Seems like an uneccesary cost unless the inspector can prove it is required by code.

What does common sense say about that?

I never said building inspectors use common sense, but I do. Common sense and experience tell me that you do what the inspectors requires or you do not pass inspection.

 

[oh'mike]

This is not aimed at the OP--Just an observation learned in my long life.

All to often a person can not see the value of a professional design or opinion ,if they must pay for it----

This leads to a lot of mistakes and reworking of the project.

A personal observation---the people who see design costs as a waste of money are ,most often, people that make their living sitting at a desk.--go figure.

 

[Anti-wingnut]

Common sense and experience tells me that you do what is legally required. The inspectors can't require anything from you other than what code states.

If your building infact has existing apartments, then you could argue that you are doing a repair and no FR system is required.

 

[Anti-wingnut]

I know how much it could cost because I looked it up how much a sprinkler system can cost. I asked in the home improvement section because I am dealing with a small structure and I am renovating a residential space.

Sprinklers for upstairs would be cheaper since it would be residential

Not correct.

You are renovating a muti-use commercial building with apartments.

A very different thing than a residence


Gypcrete is great in old buildings.

But again, nothing you do will result in any type of fire rating unless the entire assembly is done.

 

[Mingledtrash]

The International building code exists for a reason. The fire code is not something that someone just pulled out of thin air. Contrary to some peoples beliefs the laws of physics are the same on both sides of the mason dixon line. These laws of physics are what determine the code. This particular section dealing with a living space above a commercial space was written because of the countless lives that have been lost do to not have a proper partition between commercial and living/sleeping area. The reason no one will tell you what to use is because we do this for a living and understand the consequences of not having proper fire protection. We are talking after all about someones mother, brother, sister, or grandparents burning to death all because you did not want to spend the money to protect them. This is your responsibility as a building owner/landlord.

I sure as he!! wont be a part of causing the burning death of another human being and i am sure quite a few of the other professionals on here hold the same sentiments. This is why no one will give you an answer to your question.

I am not trying to debase you as i understand you dont know much about the subject, I am just trying get you up to speed with what you are dealing with and to get you to understand the gravity of the situation.

Some projects are not diy projects. this is definitively one that is not.

 

[The5thofNov.]

Yes, it was quite obvious I was getting responses from professionals, hence all of the recommendations to hire one. While I completely understand your concern for fire safety, I do not think you understand how little sense it makes to be worried about a fire a barrier between levels when the walls are made of kindling. I will satisfy the inspector, and whatever he says the code is. If I ever need professional advise on a diy forum again I will be sure to keep you guys in mind and of course will keep you in mind if I ever hire someone to do a "plan".